Dissertation seaweed insulation

Seaweed insulation 7. semester Dissertation Author: Consultant: Date:

Anna Katarzyna Plawecka Heidi Merrild October 2015

BATCoM–Bachelor of Architectural Technology and Construction Management VIA University College, campus Horsens, Denmark

Anna Katarzyna Plawecka

October 30, 2015

TITLE PAGE BATCoM- Bachelor of Architectural Technology and Construction Management

Elective title:

Seaweed insulation

Consultant:

Heidi Merrild

Author :

Anna Katarzyna Plawecka

Date/signature:

30 October 2015

Student identity number:

187988

Number of copies:

1

No. of pages:

41

No. of characters:

63.895

Font:

Calibri

All rights reserved – no part of this publication may be reproduced without the prior permission of the author.

NOTE: This dissertation was completed as part of a Bachelor of Architectural Technology and Construction Management degree course – no responsibility is taken for any advice, instruction or conclusion given within!

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Preface

This report is a part of a final examination for the Bachelor of Architectural Technology and Construction Management education at VIA University College.

The title of the report is “Seaweed insulation� and the aim of the report is to examine the potential of seaweed as a modern insulation material.

I would like to thank everybody, who helped me while writing the report with good advice and inspiration. First of all, I would like to thank my consultant, Heidi Merrild, who helped me through the process of researching and writing the report. I would also like to thank Gordon Alcock, who guided me through the rules of writing academic report.

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Abstract

The subject of the report is seaweed insulation. The aim of the report is to examine the potential of seaweed as a modern insulation material. The report contains research on usage of seaweed in building industry in the past as well as analyses of modern project and production methods of building materials made out of seaweed. The the report reflects also on material properties. Furthermore, research paper includes interview with Flemming Werk from Advance Nonwoven (seaweed insulating mat producer) as well as interview with Bodil E. Pallesen from AgroTech. Moreover, the report contains the brief description of the seaweed workshop, two information sheets gathering main properties of different types of seagrass and in the end an amateur experiment on eelgrass inflammability.

The report starts form reflecting on history of seaweed in general and then it is going deeper into specific role of this material in the building industry. Then it describes the first attempts of using seaweed again in 2000s by Seaweed Triumvirate on Læsø. The papers characterize in detail various aspects of the modern seaweed house, starting from esthetics, through sustainability and economy, finishing at construction solutions. Then the focus is turned on modern production process and the level of difficulty while working with ready product. In the end, the report describes properties of seaweed and judges threats connected with popularizing seaweed insulation.

The report concludes with the statement that seagrass has many virtues and can be competitive insulation material on the market. However, more tests are needed in order to examine deeply its properties. The threat is also insufficient amount of raw material in case of starting a production on the bigger scale.

Key words

Seaweed/ seagrass/ eelgrass/ zostera marina/ posidonia oceanica insulation - New biological insulation – History – Esthetics – Sustainability - Production process - Modern applications - Properties

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Glossary

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Seaweed- general term to describe all the plants living in the sea. From biology point of view seaweed is a marine alga and was never used to insulate houses. (www.seagrasswatch.org)

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Seagrass- only flowering plant that can live underwater. From biology point of view it has nothing to do with seaweed. Seagrass is an actual material which was/is used to insulate houses. Commonly called seaweed. (www.seagrasswatch.org)

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Zostera Marina- spices of seagrass. Appears in many places around the globe.

Commonly called eelgrass. In many publications called also seaweed. (www.iucnredlist.org). For more information see enclosure 5.

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Posidonia Oceanica- spices of seagrass endemic to the Mediterranean Sea. Called Neptune Grass or Mediterranean tapeweed. In many publications called also seaweed. (www.iucnredlist.org) For more information see enclosure 6.

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Contents

1.

Introduction with problem formulation ........................................................................ 9 1.1.

Problem background information and presentation of the subject ...................... 9

1.2.

Reasons for choice of the subject – personal relevance ........................................ 9

1.3.

Problem statement ................................................................................................. 9

1.4.

Delimitation .......................................................................................................... 10

1.5.

Choice of theoretical basis and sources of empirical data ................................... 10

1.6.

Choice of research methodology and empirical data ........................................... 10

1.7.

Choice of working method.................................................................................... 10

2.

Closer look on the seaweed ........................................................................................ 11

3.

History of seaweed in building industry ...................................................................... 12

4.

5.

3.1.

China ..................................................................................................................... 12

3.2.

Denmark................................................................................................................ 13

3.3.

Netherlands .......................................................................................................... 16

3.4.

USA ........................................................................................................................ 17

3.5.

Part conclusion...................................................................................................... 19

The seaweed triumvirate............................................................................................. 20 4.1.

Triumvirate´s activity ............................................................................................ 20

4.2.

The gathering and Seaweed Bank idea................................................................. 21

4.3.

The construction methods .................................................................................... 22

4.4.

Part Conclusion ..................................................................................................... 23

The modern seaweed house ....................................................................................... 24 5.1.

The challenge ........................................................................................................ 24

5.2.

Esthetics ................................................................................................................ 25

5.3.

Sustainability ......................................................................................................... 26

5.4.

Economy................................................................................................................ 27

5.5.

Construction.......................................................................................................... 27

5.6.

The future ............................................................................................................. 29

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5.7.

6.

7.

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Part conclusion...................................................................................................... 29

Production of seaweed insulation and its application ................................................ 30 6.1.

Seaweed insulation mats ...................................................................................... 30

6.2.

Neptune Balls ........................................................................................................ 32

6.3.

Part conclusions .................................................................................................... 33

Properties of seaweed ................................................................................................. 34 7.1.

Thermal conductivity ............................................................................................ 34

7.2.

Acoustic properties ............................................................................................... 34

7.3.

Reaction to fire ..................................................................................................... 34

7.4.

Lifespan and resistance to mold ........................................................................... 35

7.5.

All the other virtues of seaweed........................................................................... 36

7.6.

Threats .................................................................................................................. 36

7.7.

Part conclusion...................................................................................................... 36

Conclusion ................................................................................................................... 37

Bibliography ......................................................................................................................... 39 Enclosures .............................................................................................................................. 1 Enclosure 1 ........................................................................................................................ 1 Enclosure 2 ........................................................................................................................ 3 Enclosure 3 ........................................................................................................................ 6 Enclosure 4 ........................................................................................................................ 8 Enclosure 5 ........................................................................................................................ 9 Enclosure 6 ...................................................................................................................... 10 Enclosure 7 ...................................................................................................................... 11

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List of figures

Unless otherwise stated all illustrations / photographs are the work of the author Figure 1: Eelgrass on the beach (Jensen, Tængemænd og vaskerpiger, 2012) ............................................... 11 Figure 2: Seaweed as a first fridge insulation (www.seagrassli.org) ............................................................... 11 Figure 3: Timeline showing history of seaweed used as building material ..................................................... 12 Figure 5: Seaweed roof of traditional Chinese house in Jiaodong Peninsula (www.usa.chinadaily.com) ....... 12 Figure 4: Chinese seaweed houses (www.duskyswondersite.com) ................................................................ 12 Figure 6: Construction of Chinese seaweed roof (Zhang, 2011) ...................................................................... 13 Figure 7: House with seaweed roof thatching at Læsø (Jensen, Tængemænd og vaskerpiger, 2012) ............ 13 Figure 8: Seaweed roof thatching at Læsø (Jensen, Tængemænd og vaskerpiger, 2012) ............................... 13 Figure 9: Women rolling the eelgrass (Jensen, Tængemænd og vaskerpiger, 2012) ...................................... 14 Figure 10: Process on constructing eelgrass roof (Jensen, Tængemænd og vaskerpiger, 2012) ..................... 15 Figure 11 : Half-finished seaweed roof. (Jensen, Tængemænd og vaskerpiger, 2012) ................................... 15 Figure 12: Seaweed house on Læsø nowadays. (Jensen, Tængemænd og vaskerpiger, 2012) ....................... 15 Figure 13: Seagrass moving in Netherlands around 1900 (Nienhuis, 2008) .................................................... 16 Figure 14: Table showing number of bales (36 kg each) transported through the sea from the Port of Yarmouth to Boston (Wylle-Echeverria & Cox, 1999) ...................................................................................... 17 Figure 15: Cabot´s Quilt Leaflet (Cabot, 1928) ................................................................................................ 18 Figure 16: Workers gathering already dry eelgrass form the fields (around 1925) (Wylle-Echeverria & Cox, 1999)................................................................................................................................................................ 18 Figure 17 : Seaweed from Cabot´s Insulation Quilt (www.seagrassli.org) ...................................................... 19 Figure 18: Radio City Music Hall insulated by seaweed (www.seagrassli.org) ............................................... 19 Figure 19: Works on Kjeld Post Fårehus (www.tangtag.dk) ............................................................................ 20 Figure 20: Adriane´s House before renovation (www.tangtag.dk) ................................................................. 21 Figure 24: Adriane´s House after renovation (www.tangtag.dk) .................................................................... 21 Figure 22: Europa Nostra prize awarded to the triumvirate´s activity since 2007 (www.tangtag.dk)............ 21 Figure 23: Seaweed bales transported by ship (www.tangtag.dk).................................................................. 21 Figure 24: Seaweed Bank (Jensen, Tængemænd og vaskerpiger, 2012) ......................................................... 22 Figure 25: Pictures form renovation of Adriane´s House showing step by step how to build the seaweed roof.

(Jensen, Tængemænd og vaskerpiger, 2012) .................................................................................................. 22 Figure 26: The modern seaweed house (Realdania Byg, 2013) ....................................................................... 25 Figure 27: External cladding made out of seaweed stuffed into kitting net (Realdania Byg, 2013)................ 25 Figure 28: Interior of the modern seaweed house (www.dezeen.com) ........................................................... 26 Figure 29: Wooden skeleton of the house during construction process (Realdania Byg, 2013) ...................... 27 Figure 30: Prefabricated wooden element filled with dried seaweed (Realdania Byg, 2013) ......................... 28 Figure 31: Filling the nets with dried seaweed. (Realdania Byg, 2013) ........................................................... 28 Figure 32: Process of upholstering interior cladding (Realdania Byg, 2013) ................................................... 28 Figure 33: Installation of Interior cladding (Realdania Byg, 2013) .................................................................. 29 Figure 34 : Adding the binder to the material ................................................................................................. 30 Figure 35: Material during production. ........................................................................................................... 30 Figure 36: Seaweed rolls (Enclosure 2) ............................................................................................................ 31 Figure 37: Seaweed mats (Enclosure 2) ........................................................................................................... 31 Figure 38: Ridge finish out of seaweed mats (Enclosure 4) ............................................................................. 31 Figure 39: Ridge finish out of seaweed roll with seaweed mats on the sides and loose eelgrass in the middle.

(Enclosure 4) .................................................................................................................................................... 32

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Figure 40: Neptune Balls (www.fraunhofer.de)............................................................................................... 32 Figure 41: Installation of seaweed insulation produced by Neptutherm. (www.neptutherm.com) ................ 33 Figure 42: Old and new seaweed mat (Enclosure 4)........................................................................................ 36

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1. Introduction with problem formulation 1.1. Problem background information and presentation of the subject

This report is a part of a final examination for the Bachelor of Architectural Technology and Construction Management education at VIA University College. The choice of topic is inspired by growing need of finding more sustainable and environmentally friendly materials in modern building industry. The answer for this need can be new biological insulation materials, and seaweed is one of the most promising one. The report will investigate into history of seaweed used as building material, elaborate on its properties and research into use of seaweed in modern design, including production and construction methods, aspects of esthetic and sustainability.

1.2. Reasons for choice of the subject – personal relevance

The choice of the topic is inspired by personal interest in sustainable and environmentally friendly materials. I believe that the future of architecture is the design based on local, long-lasting resources which do not harm the environment.

Therefore the idea of using seaweed as an insulation material caught my attention and I would like to research into possibilities of integrating it into modern design.

1.3. Problem statement

The problem in building industry of our times is that even though there is more and more sustainable building materials discovered, architects and engineers are afraid of implementing them, because they are not convinced about their quality. New biological insulation materials, among which figures seaweed, are more subject of jokes rather than being taken in account as a proposal for insulating buildings. This attitude can be changed only by investigating into the topic and researching about the materials. This report is going to focus on seaweed, which is really promising insulation material, but most of the architects and construction architects still would not even risk thinking about actually using it in theirs projects, because in their opinion it is not really good material to use. Or is it? It is obviously hard to judge unknown, and that it how the main research question emerged: o Is it possible to use in building industry simple seaweed considered as sea waste, learn from its rich history and transform it into modern, sustainable material standing up to 21st century esthetic and technical demands, or will it always stay on the carts of history just as an old, good fairy tale?

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1.4. Delimitation

This report will focus on history, properties, esthetics, modern design, production as well as construction of seaweed insulation. This report is not going into details of any other purpose of seaweed than insulating material for buildings. Furthermore, the report will keep to commonly used terms in building industry and do not stick strictly to proper biological terms.

1.5. Choice of theoretical basis and sources of empirical data

The report will be based on Building Regulations 2010, books, articles, websites as well as interviews, seaweed workshop and an amateur experiment as sources of empirical data.

1.6. Choice of research methodology and empirical data

The report will be based mostly on secondary data-books and articles. (Primary data in form of interviews, event participation and an experiment will also be included).

The report will analyze mostly qualitative data (however, quantitative data will also be included).

1.7. Choice of working method

Frist of all I have researched all information I could find about seaweed used in the building industry. Then I started reading obtained materials, from time to time finding some new article / book relevant to the research. After the general research I decided what exactly my report should contain, I got it approved by supervisor, and I started detail research on particular sections. Along with detail research I began writing the report. During the process I have visited Advance Nonwoven, company producing seaweed insulation mats, and interviewed Flemming Werk. After that I participated partly in the workshop about using seaweed mats as a ridge finish for roofs thatched with straw. From there comes the interview with Bodil E.Pallesen. Then I added obtained information to the report and changed some of the existing parts of the report. In the end I checked everything again, read it through and handed it in.

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2. Closer look on the seaweed

For a human of XXI century seaweed is mostly a sea waste, disturbing swimming and general holiday experience. It is something unpleasant, unwanted and annoying. But it had not always been like that. Seaweed has a rich history in many areas of our lives, a lot of them the ordinary man in the street would never imagine. It also plays crucial role in the sea. It provides shelter and food for many plan and animals; it can also improve water quality. (www.mesa.edu.au)

Figure 1: Eelgrass on the beach (Jensen, Tængemænd og vaskerpiger, 2012)

Seri Indians of Mexico considered seagrass really important material. They were using seagrass almost everywhere: as a source of food, material to smoke the deer meat as well as to make either baskets or toys for children. Furthermore, they did also use seagrass to produce a medicine to treat diarrhea. Seagrass played so big role in their culture, that it even influenced the name of the month: April in their local language was called “the month when the eelgrass is mature”. (www.seagrassli.org) Moreover, through the ages seaweed had been used (and in some cases is still used) as a soil fertilizer and conditioner as well as mulch, stock supplement and above all as a fill in pillows and matrasses as well as upholstery. Furthermore, it can be used also to make furniture, mats, ropes or even shoes (www.seagrassli.org; www.mesa.edu.au) Getting closer to the insulating properties of the material, it is reported that Frigidaire´s first refrigerator produced in 1919 contained eelgrass insulation in the construction, but had to be replaced by corkboard in the mid 20´s due to smell issue. (www.seagrassli.org)

Figure 2: Seaweed as a first fridge insulation (www.seagrassli.org)

To sum up, seaweed is an incredible material with many possible applications in wide array of different fields. It was proven by history that this material can more than just lie on the beach and disturb dream holiday. The next chapters show that seaweed had been equally valuable material for building industry and definitely deserves more than just being called a sea waste.

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3. History of seaweed in building industry

The idea of using seaweed as insulating material is not new. It was used through the ages in many different parts of the world. However, the technique and the way it was used is not precisely the same. This chapter will analyze circumstances and reasons of using seaweed as a building material, methods of gathering and construction solutions, and in the end cause of its disappearing.

1600 B.C.

XVII century

Traditional Seaweed Houses China

First settlers on Long Island (USA)

Xlll century Denmark Læsø

1930s seagrass disease

The Netherlands

1890s Cabot`s Quilt Insulation

1907-1960 Gathering in USA

1930 Guildfords Limited, Nova Scotia

Figure 3: Timeline showing history of seaweed used as building material

3.1. China

Sources point on China as the place where seaweed was used in building industry for the first time. Some publications also speculate usage of seaweed in Europe at that time, but because of lack of evidence it is not possible to confirm this hypothesis. The first “seaweed houses” were mainly scattered over Jiaodong Peninsula (costal area of Shandong Province) and they started appearing in early stage of Shang and Figure 5: Chinese seaweed houses (www.duskyswondersite.com) Zhou Dynasties, which dates back to 1600 B.C. The houses were really simple at the beginning, but with the time the technique of construction gradually improved. The seaweed houses were a perfect solution for temperature monsoon climate – their two meter thick stonewall and seaweed roof was natural thermal insulator and kept houses warm in winter Figure 4: Seaweed roof of traditional and dry in summer. The houses started disappearing Chinese house in Jiaodong Peninsula in XX century partly because of illness which (www.usa.chinadaily.com) significantly decreased the seaweed population. (www.china.org)

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Construction solutions

According to the traditional working methods, seaweed should be placed directly on the battens and cover the timber skeleton in turns. A layer of seaweed was 100 mm thicker at the ridge in order to enlarge the roof slope and facilitate drainage.

Each layer of seaweed was followed by wooden frame in order to prevent seaweed being blown away form the roof. Wooden frame created also an air gap between seaweed layers, which was lightening, insulating and sealing the whole construction. Every wooden frame was fixed and Figure 6: Construction of Chinese seaweed linked with timber frame underneath. This construction process requires tree or four people to roof (Zhang, 2011) work constantly 10 days. All work was done by hand. (Zhang, 2011) (www.chinadaily.com) 3.2. Denmark

It was actually one specific part of Denmark, where the special method of building seaweed roofs was invented. The method of building is now an exceptional part of cultural heritage of Denmark and catches attention all over the world. This place is an island on the north of Denmark, called Læsø.

First seaweed houses started appearing there in XIII century, after the Viking era, when first inhabitants arrived on Læsø. The island was rich in salt, and they were attracted by possibilities of harvesting salt.

Unfortunately, besides high salt concentration the island was poor in building materials known at that time – there were no lakes with reed and the soil type did not give much hope for farming. However, the island was rich in forests and plenty of eelgrass lying on the coast. That is probably why the first inhabitants of Læsø, being used to straw thatched roofs, decided to replace missing building material

Figure 7: House with seaweed roof thatching at Læsø (Jensen, Tængemænd og vaskerpiger, 2012)

Figure 8: Seaweed roof thatching at Læsø (Jensen, Tængemænd og vaskerpiger, 2012)

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with eelgrass. (Jensen, Naturens eget tag, 2014) According to Jensen seaweed houses existed also on Halland in Sweden and on two islands in Horsens Fjord – Endelave and Hjarnø – but they do not represent as important cultural heritage as the unique houses from Læsø. The reason of that is the fact that they were constructed just due to lack of other resources and the technique of building the seaweed roofs was not exceptional. (Jensen, Tængemænd og vaskerpiger, 2012) Gathering methods

Seaweed was collected from the beach with horse carriages and placed on the fields to dry out. There seaweed was drying for around 14 days, after that it was collected again and stored. (Jensen, Naturens eget tag, 2014) Construction solutions

The first seaweed roofs were easy and fast to build and did not require deep construction knowledge.Loose eelgrass, a type of seaweed used at Læsø, was just placed on top of the roof skeleton and fixed to it in many different combinations, which yet did not resemble the method of fixing used for constructing straw thatched roofs at that time. This simple method had one big disadvantage: loose eelgrass was heavy, which created a challenge of constructing load-bearing structure strong enough to withstand the weight of seaweed.

Roofs made out of loose seaweed were being constructed trough following around four up to five hundred years. (Jensen, Naturens eget tag, 2014) During these centuries many things happen. Production of salt led to deforestation of the island, and despite of many tries the salt business ended. Many people decided to move out from the island and Læsø became deserted. That became a reason of really characteristic division of work which appeared around XVIII century. Men were mostly sailors, and when they were back on the island they were either fishing or collecting timber form ship wrecks around the island. On the Contrary, women had to take care of the fields, family and house, and that included also construction of buildings. (Jensen, Naturens eget tag, 2014) In the construction process were involved almost all women from the island. That means that at the “building site” could be even 100 people in one day. Women working with the eelgrass were called “vaskerkoner” or “vaskerpiger”. As it is shown in figure 9 and 10, women were working in pairs, rolling and turning the piece of eelgrass to obtain the sausage-like shape (“vasker” in Danish). Seagrass rolls were tied to the lowest timber rack

Figure 9: Women rolling the eelgrass (Jensen, Tængemænd og vaskerpiger, 2012)

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in the roof, so the rest of the seaweed can bear on them.

The work was managed by a man, who was experienced in carpentry. He was the one tying seaweed to the battens and making sure the roof had the right thickness and airtightness. Even though it may be surprising, that the Figure 10: Process on constructing man was the one leading eelgrass roof (Jensen, Tængemænd og the work, everything has its vaskerpiger, 2012) explanation. The timber used for the construction was coming from ship wrecks and only the carpenter could estimate if each piece of timber is Figure 11 : Half-finished seaweed strong enough in order to use it in the construction. roof. (Jensen, Tængemænd og vaskerpiger, 2012) (Jensen, Naturens eget tag, 2014) What happened with seaweed houses at Læsø

The last fully thatched roof was built in 1870s. Later on roofs were only renovated, but it did not last long. Eelgrass was decimated by fungus illness in 1930s, which led to the end of seaweed era on Læsø. In XIX century there was around 230 seaweed houses at Læsø, in 1970s the number dropped to 90.

In 1951 women from Læsø were invented by Danish museum to thatch a new eelgrass roof. The process was recorded and photographed and is now the main source of information about the construction solutions that are now unique cultural heritage of Læsø Island.

Figure 12: Seaweed house on Læsø nowadays. (Jensen, Tængemænd og vaskerpiger, 2012)

In 1955 the Læsø´s museum opened. It was located in the old building which eelgrass thatched roof renovated with 40 tons of seaweed bought form Kallehave Tang-Export form Zealand, close to both Møn and Bogø Islands. In the best period the company was employing around 40 people and exporting seaweed to many countries for insulating purposes as well as matrasses filling. Unfortunately the company closed in 1959 and for some decades the world forgot about eelgrass.

Nowadays there are around 20 houses left, most of them being forgotten and slowly falling into decay, until seaweed return on the island in 2000s, which will be described in next chapter. (Jensen, Naturens eget tag, 2014)

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3.3. Netherlands

In Netherlands the first use of seagrass is dated back to 14th century, where it was used to reinforce levees on Wieringen Island in North Holland. The island was frequently flooded and that is why levees were in high need. According to Nienhuis “the dried weed had the advantage that it compacted to a hard almost stone-like mass that was rather resistant to wave attack�. (Nienhuis, 2008, p. 442) Later on, in 16th century, eelgrass together with wood was used to build 2 m high dyke. Dyke`s remains which survived to our times are the proof of exceptional durability of eelgrass. Nienhuis also mentions that seaweed in Northern Europe was used to thatching roofs. (Nienhuis, 2008) More information is available about 18th and 19th century. Seaweed was gathered either directly from the sea or form tidal flats, dried and used as roof thatching and insulation.

During renovation of castle Waardenburg on river Waal in 2007 it was revealed that part of the ceiling construction contained layer of eelgrass in perfect conditions, even though it is assumed that it lied there at least 150 years. (Nienhuis, 2008) 19th century and the industrial gathering

In 19th century seaweed became popular building material and a source of main income for many fishers. In 1826 the first industrial moving of seaweed started. This seaweed, gathered directly from the water, was better quality than the one collected on the beach.

It was gathered by people standing in half-tide water who moved the eelgrass with an elongated scythe, gathered it to the net and then speeded it to dry partially on the field.

After that seaweed was staying in freshwater ditches for certain amount of time in order to take the salt out of the plant, then dried again. In the end seagrass was transported to warehouses and pressed in special weed-press into bales ready for shipment. (Nienhuis, 2008) The end of seaweed business

Due to the construction of Closure Dike (major causeway in the Netherlands) in 1920s tidal currents and patterns of sedimentation in Wadden Sea changed. It resulted in destroying seaweed beds, which never recovered. This led to an end of seaweed gatherings in Netherlands.

(Nienhuis, 2008) Figure 13: Seagrass moving in Netherlands around 1900 (Nienhuis, 2008)

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3.4. USA

In XVII century early settlers arrived on Long Island in North America. It is documented, that they were using eelgrass as an insulating material for homes. They were making socalled “banking up” which consisted of layering outer walls of the buildings with loose, dry leaves of Zostera Marina. The early settlers were also using Zostera Marina to fill up various air gaps in the construction. In the result humans and animals were protected from cold in winter and warmth in summer. Eelgrass was used as well as a bedding material for livestock and mulch for gardens. The first settlers of North America were gathering Zostera Marina for non- commercial, private use. (Moe, 2014) (WylleEcheverria & Cox, 1999) The example of building from those times is Old Pierce House in Dorchester, Massachusetts in New England, build in 1683. During renovation works in 1893 dried eelgrass was found between timbers framing of the structure. It might be that the eelgrass used in the construction caught attention of Samuel Cabot, who at that time came up with the idea of using seaweed as heat and sound insulating product, known as Cabot’s Quilt insulation. That is also when the commercial gathering of seaweed started.

The house stands today. (Moe, 2014) (Wylle-Echeverria & Cox, 1999) Yarmouth County was the place, where early commercial gathering took place, and everything was driven by manufacture of a seagrass quilt in Boston, Massachusetts, USA. The gatherings did not require big capital, because participants usually were farmers or fishers and they could use equipment they possessed. The big advantage was the time of gathering (late July-October) which did not conflict with farming or fishing time.

Then seagrass was first purchased exclusively by Samuel Cabot Insulation Quilt, and after that also by another company, Guildfords Limited from Dartmouth in Nova Scotia. Data extracted form newspapers form years 1907-1931 shows, that from 102 bales in year 1907 the production reached 12854 bales in 1929 (Figure 14). Each bale weighted approximately 36 kg., which means, that in 1929 almost 463 tons of seagrass was produced. The business expanded so much, that

Figure 14: Table showing number of bales (36 kg each) transported through the sea from the Port of Yarmouth to Boston (Wylle-Echeverria & Cox, 1999)

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Samuel Cabot`s company started to import seagrass form other countries, such as Germany or Netherlands. Even the famous Titanic had some Dutch eelgrass cargo on board. (Nienhuis, 2008) In early 1930s the disease significantly reduced or eliminated the population of Zostera Marina and number of bales produced dropped significantly. It prevented gatherings in Yarmouth County until 1939 and forced companies to import seagrass form River Herbert in northern Nova Scotia and form Germany.

However, due to Word War II and lack of sufficient seagrass resources in America the production of seaweed insulation stopped. Guildfords limited tried to continue production in 1950s, after recovering seagrass form disease, but in result of advancement of other Figure 15: Cabot´s Quilt Leaflet insulation materials such as fiberglass and other (Cabot, 1928) synthetic fiber products it did not succeed and the commercial gatherings of eelgrass in United States were suspended in early 1960s.

(Wylle-Echeverria & Cox, 1999) Gathering

The specific thing about the Yarmouth County was the 75 m long rock wall built in order to capture seagrass before it will reach the coast. The eelgrass was forked form the wall and placed on the ox carts. In other parts of Yarmouth County the leaves were captured directly from the water or from the rocks. Then it was spread on the freshly moved hay fields to dry and turned from time to time. When eelgrass was thoroughly dry, it was transported to one of fourteen collection shed owned by Samuel Cabot. The sheds were equipped in two types of balers. One was an iron hay baler and another wooden hand press. Ready bales were stored until shipped to Boston. (Wylle-Echeverria & Cox, 1999) Guildfords Limited used to gather seaweed in exactly the same way, with the difference of transporting loose seagrass rather than baled leaves. (Wylle-Echeverria & Cox, 1999)

Figure 16: Workers gathering already dry eelgrass form the fields (around 1925) (Wylle-Echeverria & Cox, 1999)

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Material description

Cabot`s Quilt Insulation, popularly called just Cabot`s Quilt, was a material made by stitching layers of dried eelgrass in various thickness between heavy Kraft paper.

It was available in three variations: single-ply (80 mm) for single-family houses, double-ply (127 mm) for additional sound insulation and asbestos single or double-ply (covered with asbestos instead of paperboard). Later other varieties became available, ending up in eight different products. Cabot`s Quilt was used for wide array of building types, from family houses, through apartment buildings, offices, schools and lecture halls up to hospitals and warehouses on the territories United States, Canada and Great Britain, Australia, New Zealand, Sweden, Finland, Holland and Argentine Republic. (Moe, 2014) Many buildings in New York built at that time, including Carnegie Hall, Radio City Music Hall and Rockefeller Center were insulated by Cabot`s Quilt due to its brilliant sound properties. (Wylle-Echeverria & Cox, 1999) (www.seagrassli.org)

Figure 17 : Seaweed from Cabot´s Insulation Quilt (www.seagrassli.org)

Figure 18: Radio City Music Hall insulated by seaweed (www.seagrassli.org)

Construction solutions

Enclose 2 contains Cabot`s Quilt leaflet with technical details of construction solutions for either new or existing buildings. Even though the insulation solutions are not perfect form nowadays point of view, brochure like this one encouraged architects to start using insulation in the construction. (Moe, 2014) 3.5. Part conclusion

We can learn a lot from the rich history of seaweed in building industry. It has been proven, that seaweed is a strong, durable material, with good thermal insulation properties. Examples of Chinese and Læsø`s seaweed houses show, that it can be used as a long-lasting roof thatching which can withstand difficult weather conditions. Also examples of Netherlands and America exhibit exceptional lifespan of seaweed. The Cabot`s Quilt Insulation proved that seaweed used as sound and thermal insulating mat is easy to install and good quality product which can be manufactured on large scale.

Comparing gathering methods it is clear that the seaweed gathered directly from the water is a lot better quality than the one collected form the beach. The threating

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methods are really similar in all the countries, only Netherlands stands aside with their method of desalting seaweed until it is thoroughly dry, but since there is not much information available we cannot assess how much it changes seaweeds properties and lifespan.

According to construction methods, it is hard to examine whether loose seaweed or seaweed pressed in bales has better insulating properties. Generally speaking it also depends on where the material should be used. Seaweed mats are of course easier to work with, but they also require more processing than loose seaweed.

All in all, the seaweed`s rich history in building industry gives a lot of possibilities to build on. The past of seaweed can become a good starting point in order to create new ideas of applying seaweed into modern building industry.

4. The seaweed triumvirate The history of seaweed did not end in XX century, it just stayed forgotten until the initiative started in the first decade of 2000s by “Seaweed Triumvirate” at Danish island Læsø. The triumvirate consisted of two inhabitants of Læsø, farmer Henning Johansen and businessmen Poul Christensen, together with architect Marcelle Meier.

The triumvirate was well matched. Henning Johansen was roof thatcher at Læsø who knew how to work with eelgrass, Poul Christensen was his neighbor who succeeded in obtaining funds for Læsø´s salt production, and Marcelle Maier had strong theoretical knowledge about seaweed due to the fact that her master theses were about unique seaweed thatched roofs. In the other words, they had all type of experience needed: practical, theoretical and economical. (Jensen, Naturens eget tag, 2014) 4.1. Triumvirate´s activity

The triumvirate, together with Rune Ottesen, a museum´s thatcher trainee, began the work form thatching the roof of newly built Kjeld Post Fårehus. The project was financed by Realdania and brought first experiences of working with seaweed. The first three tons of material delivered from Bogø did not stand up to quality standards, but the next transport containing seaweed just after harvest was totally fine. That was the lesson, that quality of seaweed matters: “We have all learned that seaweed is not just seaweed” commented Henning Johansen, initiator of the triumvirate. (Jensen, Naturens eget tag, 2014, p. 163)

Figure 19: Works on Kjeld Post Fårehus (www.tangtag.dk)

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After completing roof of Kjeld Post Fårehus the group continued with small renovations of existing seaweed roofs, until the decision was made that in 2011 the “Adirane´s House” should be renovated thoroughly and a new seaweed roof should be thatched. First time since 1870s a completely new eelgrass roof was build. For these single construction 35 tons of seaweed was used. (Jensen, Naturens eget tag, 2014) In 2012 Realdania Byg purchased “Kaline´s house”, which is another old seaweed house on Læsø, and renovated it. (Jensen, Naturens eget tag, 2014) In the same year the prestigious Europa-Nostra prize for Cultural Heritage in category: Education, training and awareness rising was awarded to the triumvirate´s activity since 2007, which included establishment of Seaweed Bank and the plan of rescuing the last existing seaweed houses in the world. General interest in seaweed roofs grew, and that led to initiative of using this material in new, modern ways. (Jensen, Naturens eget tag, 2014) (www.tangtag.dk)

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Figure 20: Adriane´s House before renovation (www.tangtag.dk)

Figure 21: Adriane´s House after renovation (www.tangtag.dk)

Figure 22: Europa Nostra prize awarded to the triumvirate´s activity since 2007 (www.tangtag.dk)

4.2. The gathering and Seaweed Bank idea

Seaweed is gathered and dried on two Danish islands, Møn and Bogø, and then transported to Læsø. It should be gathered immediately after appearing on the beach: “Seaweed should be gathered form the beach and dried as soon as possible, the best in the same day. It lies for a long time in warmth without any risk of moisture, processes which are decomposing the fibers in seaweed starts.” These are words of the farmer and seaweed fisher form Møn, Ib Ungermand (Realdania Byg, 2013, p. 3)

Figure 23: Seaweed bales transported by ship (www.tangtag.dk)

Because eelgrass is a living plant, the harvest time is not constant, and it depends a lot on the water condition. Some years waters may be rich in eelgrass, some not. This infrequency in harvest time forces seaweed to be gathered when possibility occurs, and that leads to costs of storing huge quantities of eelgrass for unprecise amount of time. The solution for that is Seaweed Bank, which should always have at least 100 tons of eelgrass on stock. (www.tangtag.dk)

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The bank itself is not a cheap thing, but the idea caught the attention of the public and many sponsors decided to donate money in order to help with establishment of such seaweed storage. The role of the bank is to buy and sell seaweed for each individual renovation project as well as to take care of the process of registration and arrangement of replacement of existing seaweed roofs so that the possibilities of improving construction techniques and working method are examined. The future aim is to Figure 24: Seaweed Bank (Jensen, Tængemænd og vaskerpiger, 2012) mechanize the construction process so that construction period is shorter and working method is easier. The Bank tries also to change thatching law in order to use seaweed as a material on a straw roof which would in that case replace heather. (www.tangtag.dk) Organization is said to be non-profit and the money from the seaweed sell are just for covering the expenses of transportation and other costs of running the Bank. The Seaweed Bank on Læsø is managed by Seaweed Triumvirate members. (www.tangtag.dk) 4.3. The construction methods

The construction method used by Seaweed Triumvirate is based on traditional Læsø´s technique of thatching seaweed roofs with few modern improvements. The starting point is a good quality, well-dried eelgrass of appropriate length. Another important issue is accuracy in creating rolls out of seaweed. The better they are made and fastened to the battens, the longer the roof will last. (Jensen, Tængemænd og vaskerpiger, 2012) Figure 25 shows how such a roof is built step by step. The first step is to twist the seaweed so the rolls are created. The Figure 25: Pictures form renovation of Adriane´s House process is mechanized with the use of showing step by step how to build the seaweed roof. (Jensen, electronic screwdriver on one side of the Tængemænd og vaskerpiger, 2012) seaweed roll and electronic machine built by local electrician on the other side. The machine requires assistance of three men, but

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on the contrary the process is at least twice as fast as the traditional one. (Jensen, Tængemænd og vaskerpiger, 2012) After rolls are ready they have to be lifted by two men each and tied strong to the lowest roof batten. Then space between the tied rolls is filled up with non-tied rolls. And the process is continued until the three lowest racks are ready. They should be altogether around 180 cm thick. (Jensen, Tængemænd og vaskerpiger, 2012) Then the wooden skeleton of the roof is covered with fir, pine or spruce branches preventing the seaweed to fall inside the house though gaps between battens. Finally, loose seaweed is placed on the roof, filled in the gaps and stepped on in order to strengthen the construction. On top of the seaweed is laid a turf ridge, which will blend with seaweed after some time. (Jensen, Tængemænd og vaskerpiger, 2012) (www.naturalhomes.org) When the construction is finished roof requires few months so the seaweed falls a bit down and the structure becomes more dense and strong. Then the openings for windows and doors in the roof are cut using nowadays petrol-powered hedge trimmer. (Jensen, Tængemænd og vaskerpiger, 2012) After about one year roof changes the color to silvery grey, it´s structure becomes more solid and plants starts growing on top of seaweed thatching. It is also the time when the roof becomes waterproof. Even though the seaweed thatching is not initially airtight, its thickness does not allow any water to penetrate through anyway and no damages occur because of that reason. (www.naturalhomes.org) 4.4. Part Conclusion

Generally speaking Seaweed Triumvirate achieved a lot. The most important thing is that it brought back to llife the forgotten tradition of thatching roof with seaweed. Many houses were renvated and some new were build. Fruthermore, the Seaweed Bank was established ensuring inhabitants and investors that the material will be always avaliable.

Last, but not least, the activity of Seaweed Triumvirate got noticed and awarded by honourable price Europa-Nostra in 2012. All of these achievement made the island and seaweed more known. On the other hand, the activity of Triumvirate, even though excellent while repearing old seaweed roofs and maintaining tradition, did not improve the working methods and old house outlook. If the material should be used in modern buildings, the esthetics and building process also need to stand up to nowadays standads, and Seaweeed´s triumvirate proposal did not fulfil these needs. However, they reminded

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the world about valuable, old building material, which possibilities can reach far beyond simple roof thatching.

5. The modern seaweed house Restauration of traditional seaweed houses on Læsø and activity of Seaweed Triumvirate have proven that seaweed plays its role as an insulator and roof thatching, but it was still not clear, how the material could be use in contemporary design. Something had to be changed, because not everybody fancies living in traditional seaweed house with few tons of eelgrass used as a roof thatching. Therefore the idea of building the modern seaweed houses emerged.

5.1. The challenge

Realdania Byg is a non-profit organization which has been supporting the activity of Seaweed Triumvirate since the beginning. This organization founded the new roof of “Kjeld Post Fårehus” and later on bought and then renovated the “Kaline´s house” in 2012. And it actually was the same organization, which have bought the land on Læsø and decided to build a modern house made out of seaweed. (Ehmann, Klanten , & Borges, 2014; Jensen, Naturens eget tag, 2014) Realdania announced a competition in 2012 for designing a modern summerhouse on Læsø. The new seaweed house was supposed to be mostly a material experiment, which was an attempt to try out the same materials used in traditional seaweed houses, but in new, modern ways. The project was supposed to be sustainable not only in environmental aspect, but also in economical. In the other words, it was required, that the cost of the building fits in the budget of any other summerhouse of similar size.

Furthermore, the house was supposed to stand just nearby freshly renovated “Kaline´s House”, which meant, that its appearance has to match to traditional seaweed houses on the island. (Realdania Byg, 2013) The competition organized by Realdania Byg won Vandkunsten Tegnestue, Architectural office from Copenhagen. They came up with the design of the house, which “combines the traditional material with twenty-first century construction techniques,” as Jørgen Søndermark from Realdania Byg summed it up (www.dezeen.com).

Indeed, the design of the house does not stand out form modern architectural norms, even though the main material used for the construction is not that modern seaweed.

“We have used natural materials in the modern way, and we had luckily a client, that was willing to experiment” says Søren Nielsen, architect maa from Vandkunsten Tegnestue (Jensen, Naturens eget tag, 2014, p. 167)

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The results of this experiment are quite impressive.

The house is built in simple, long traditional shape characteristic to the island, with seaweed cladding composed gently into the form. The Vandkunsten Tegnestuen took care of details: the size of the building, duo-pitched roof, or even East-West orientation is matching perfectly with the Læsø´s tradition as well as local planning restrictions, which Figure 26: The modern seaweed house makes the house literally blend in the environment. (Realdania Byg, 2013) Only the small elements of design, beyond which the most distinctive is seaweed external cladding, indicate the modernity of the project.

(Realdania Byg, 2013; Ehmann, Klanten , & Borges, 2014) 5.2. Esthetics

Seaweed is a challenging material for an architect, because it is completely opposite of precision – it´s irregular, messy and unstructured. On the other hand, in the modern architecture really important is precision. Lines should be straight and edges sharp. By that architects create a rational and perfect world, which in real life is really hard to achieve. For an average man perfection is something beyond his abilities, and it results in less and less people actually believing in it. Understanding it in this way, the conclusion can be that adding some softness to the building´s straight lines and sharp edges which actually can make the building easier to relate to for people of our times, who are not craving for perfection any more, but they still need some kind of balance in their lives.

(Realdania Byg, 2013) Following this thought the architect maa Søren Nielsen form Tegnestuen Vandkunsten cape up with the idea of the modern seaweed house´s design. He decided to find a balance between the softness the material the perfection and proposed to use as external cladding the cylindrically shaped nets filled with eelgrass. Each building element was supposed to Figure 27: External cladding made out of seaweed stuffed into kitting net (Realdania have certain amount of cylinders installed inside the Byg, 2013) wooden frame. In this way a structure of rhythmical vertical and horizontal elements was created, and a softness and irregularity of the seaweed was balanced with a precision of repetitive simple pattern. “The building vibrates lively between abandon and discipline”, as Søren Nielsen had summed it up.

(Realdania Byg, 2013, p. 34)

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Interior design, despite its simple form, also brings some novelty. The uncommon choice was a ceiling finish made out of linen cloth stuffed with eelgrass. Upholster Brian Liebeck admits: “To find a right fabric had been itself a challenge. Only after checking at least hundred different fabric samples in cooperation with the architects we came up with the final solution. It is a light linen fabric, which can last up to twenty years, if it is properly maintained.” (Realdania Byg, 2013, p. 5) The architect´s initial idea was to install one unbroken piece of Figure 28: Interior of the modern seaweed house (www.dezeen.com) cloth at the ceiling in order to create the impression of being in the tent, but due to the necessity of prefabrication this idea could not be fully realized.

However, even though the element´s breaks are visible, the ceiling still gives incredible impression of coziness, which does not appear so often in modern architectural design.

Another virtue of the internal cladding is its excellent acoustic properties, owing to either eelgrass or soft linen textile. (Realdania Byg, 2013) Wood is the second material significant in the modern seaweed house´s design. It appears almost everywhere. Larch, pine or spruce battens are main part of house´s construction. Furthermore, they appear in most of the finishes such as floors, internal cladding or even kitchen table. But even though three matches perfectly as a background for exterior seaweed cladding, it deserves also to be appreciated individually. Timber is never the same, and despite of the fact that these unpredictable and unstructured differences in wood grain and wood color can be challenging to the ones admiring perfection, it hard not to enjoy the beauty of it. Wood is an amazing material, because it changes with time and makes building alive. (Realdania Byg, 2013) 5.3. Sustainability

Jørgen Søndermark from Realdania Byg said : "By using seaweed in the construction, we not only secure the continued supply of seaweed for use on the historic houses, we also reintroduce a material to the modern building industry which is CO2-reducing, environmentally friendly and sustainable in a broader sense." (www.dezeen.com) Indeed, seaweed is a natural material of the sea, which can be gathered and processed with remarkably little amount of energy. Together with wood, they both produce negative carbon dioxide footprint and have a huge advantage towards other buildings in energy consumption calculations just form the start. Furthermore, the building is said to consume no more energy than 20 KWh per meter squared per year, which stands up to highest energy requirements in Denmark and fulfils energy frame 2020. This is achieved due to composition of many passive elements in the house, starting from high pitched

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roof in order to maximize the passive solar heating through skylights, through airtight construction, thick layer of insulation and triple-glazed windows, ending with mechanical ventilation with heat recovery and heat pump. (Ehmann, Klanten , & Borges, 2014; www.bygningsreglementet.dk) Generally speaking, sustainability is becoming more and more important aspect of modern building industry. Søren Nielsen describes it perfectly: “The modern seaweed house on Læsø is not just a tale about innovative applications of a renewable material in a distinctive place with a rather unusual buildings history. It is also a crystal ball, which captures and enlightens many of the most vital problems the building industry is facing today.” (Realdania Byg, 2013, p. 13) 5.4. Economy

The modern seaweed house can be considered sustainable not only environmentally, but also economically. The goal of the project was to fit into budget of standard Danish summerhouse of similar size, and due to prefabrication it managed to be fulfilled.

Moreover, owing to prefabrication the prize of the building fell according to the estimations, and that allowed realizing more expensive ideas in the project, such as upholstered ceilings or energy-saving installations. The price of the construction turned out to be 2 million DKK excluding taxes. (Vandkunsten Tegnestuen; Ehmann, Klanten , & Borges, 2014; Realdania Byg, 2013) Furthermore, it is not required to maintain the seaweed elements of the house, and the expected lifespan is comparable to similar house built with standard materials. (Ehmann, Klanten , & Borges, 2014)

5.5. Construction

The modern seaweed house built with prefabricated wooden element resting on the wooden skeleton. The insulating material of all elements, the same as internal and external cladding of the house is made out of seaweed. The decision of Figure 29: Wooden skeleton of the house during construction process (Realdania Byg, 2013) prefabrication was taken due to financial issues and really tight time schedule, and in result elements were produced in three workshops in different parts of Denmark: one in Frederiksberg in Copenhagen, another one in Kongerslev in Northern Denmark, and the last one on the Møn Island. (Realdania Byg, 2013)

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The wooden skeleton of the house was produced in Kongerslev in Northern Denmark, and then wooden modules were packed on a truck and shipped to Læsø. To transport all the modules process needed to be repeated five times. After that the wooden skeleton was mounted on pile foundations, which were chosen due to moist climate on Læsø in winter time. (Realdania Byg, 2013) The wooden floor, roof, and wall elements stuffed with seaweed were a lot more challenging to work with. The company was used to work with firm insulation materials and dried seaweed was completely opposite of that. It had to be separated from each other in order to obtain a loose material. To be sure that the elements have sufficient uvalue loose seaweed needed to be weighted before placed in the element. To that process a hanging butcher´s weight was used. (Realdania Byg, 2013)

Figure 30: Prefabricated wooden element filled with dried seaweed (Realdania Byg, 2013)

Even more complicated was working with exterior cladding. It was the task of the Praktisk Service company form Møn Island. The seaweed was stuffed into net made out of brown knitting wool. The net was handmade, but it was knitted in the way, that it possible to be industrialized in the future. The biggest challenge was stuffing the seaweed into woolen “sleeves” to obtain an equal thickness of the bolster on the whole length. It was obtained by carefully filling in the dry eelgrass trough short Figure 31: Filling the nets with dried plastic pipe. The process required a lot of skill, but it seaweed. (Realdania Byg, 2013) succeeded. (Realdania Byg, 2013) There were two different types of external cladding. The roof bolsters were thicker and softer. They were fixed to spruce rafters and then fasten to trusses. That is why their needed to be 6 meters long. The wall bolsters should fit on the wall elements, so they were shorter and harder. On one wall element could fit around 15 bolsters. (Realdania Byg, 2013) (Ehmann, Klanten , & Borges, 2014) To integrate the structure of the roof dense roofing felt was placed between wooden roof elements and seaweed cladding. During the time it is expected that as a part of natural process of weathering the roof will become a habitat of plants and birds. (Ehmann, Klanten , & Borges, 2014) The interior cladding is another unconventional element of the house. It is made out of panels upholstered with linen fabric and

Figure 32: Process of upholstering interior cladding (Realdania Byg, 2013)

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stuffed with seaweed. Fortunately the technique was similar to the one used before 1960s to produce matrasses out of seaweed, so the process was not so new, it just required a lot of time, since the method of upholstering did not change much since 1600s and was mostly handmade. The panels 2,4 meter long and 0,6 meter wide were first filled with dried seaweed, then upholstered first with fireproof layer, and at then with the visible one made out of linen. (Realdania Byg, 2013) Even though the work is mostly handmade, the precise sizes of panels could not be possible to predict if not advanced architectural 3D software, especially while talking about the panels at the ridge or around skylights. The wooden panels were manufactures with CNC cutting machine.

(Realdania Byg, 2013)

Figure 33: Installation of Interior cladding (Realdania Byg, 2013)

The expected lifespan of the linen fabric is around 20 years, if it will be maintained correctly and not exposed too much to the sunshine. (Realdania Byg, 2013)

5.6. The future

The project on Læsø has shown the possibilities of sustainable, environmentally-friendly building industry. "The seaweed houses on Læsø are physical testimony to the culture and the life that have characterized the building tradition on the island for centuries," said Realdania Byg director Peter Cederfeld. "It is our hope that others will embrace the experiences from this project and develop the ideas even further." (www.dezeen.com) 5.7. Part conclusion

The example of the modern seaweed house on Læsø has shown that it is possible to use a really old building material such as seaweed and adjust it to today´s standards of esthetics and functionality. Furthermore, the project had proven that it is possible to build a seaweed house with the same budget and time schedule as similar-size building made out of standard materials, but with the significant difference in carbon dioxide footprint.

Moreover, the techniques of prefabrication used in the project (or the possibility of mechanizing the work in case of woolen knitting nets production) create the way to lower the price even more due to rise of demand of the product. In the end, the project got interest of many people all over the world and turned the attention on Læsø and its unique building techniques.

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6. Production of seaweed insulation and its application

This chapter will describe the various modern methods of producing seaweed insulation material and evaluate the sustainability of each of them as well as analyze the efficiency of each method and the level of difficulty while working with the ready product.

6.1. Seaweed insulation mats Seaweed insulation mats are produced by Advance nonwoven, which is an international company using natural fibers, waste or recycled materials to production various purposes mats. The company is using unique CRAFT technology which is yet the only one on the world, according to the interview with Flemming Werk form Advance Nonwoven (Enclosure 2) Source of seaweed

According to the interview with Flemming Werk form Advance Nonwoven (Enclosure 2) seaweed is gathered on Bogø Island and transported to the company´s production hall in Roende in Northern Denmark.

Production Method

Flemming Werk from Advance Nonwoven A/S explains the exceptional production process as following: “The raw material first goes through hammer mill, and goes through a fiberizer and into storage boxes (hopper feeder and weighing system) and then the binder is added to the material mixed in “mixer.” After that the material is going through the Figure 34 : Adding the binder to patented CAFT technology machine which creates desired the material density and thickness of the mat. Then the mat goes to the oven where the heat is used to bond the fibers. In the end mat is cooled down, cut into required sizes, winded or stacked and packed, wrapped.” (Enclosure 2) Sustainability aspect

According to the interview with Flemming Werk form Advance Nonwoven (Enclosure 2) the technique of producing seaweed mats or mats form any other natural fibers as well as recycled materials and waste can be considered really sustainable and futuristic. The company is able to reuse wide array of materials until the point that fibers are too short to be reused, which basically means that the only thing that remains form the material is a bit of dust. Additionally, despite consuming the

Figure 35: Material during production.

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fuel and energy the machines do not pollute the atmosphere, due to installation of the special Co2 filters.

Installation of the insulation

Since the product is still at the testing stage, no certain construction method had been developed. However, the seaweed mats are consistent in structure and can be produced in various sizes and forms (see figures 36 and 37), so there is variety of applications available. Generally speaking, seaweed mats has a potential of being used as insulating material in the form we are used to. In other words, they can replace standard, inorganic materials such as mineral wool or polystyrene and be placed in traditional way as insulation inside wall, roof or storey partition construction.

Figure 36: Seaweed rolls (Enclosure 2)

Figure 37: Seaweed mats (Enclosure 2)

Furthermore, the project carried out in collaboration between Henning Johansen, LÌsø Seaweed Bank, Advance Nonwoven and AgroTech and the support of MUDP (Danish Environmental Technology and Demonstration Department under the Environmental Protection Agency) is researching weather seaweed mats can be used as a ridge finish on the straw roofs. The project started 1st of January 2015 and is expected to be finished 30th of September 2016. (Enclosure 4) The project is examining whether seaweed mats are better solution of straw roof ridge finish in comparison with existing ones. The new material is expected to have longer lifespan be easier to work with. In addition, the seaweed is famous of its poor flammability, which would be an advantage.

The project is also researching into the best construction method of building up the seaweed ridge. During the workshop, which took place on 23th October 2015(Enclosure 4), various solutions had been tested.

The initial idea was to place seaweed mat rule on the ridge, with the roofing felt on one side and without on the other side, and fix it with a metal net. However, thatchers decided to try

Figure 38: Ridge finish out of seaweed mats (Enclosure 4)

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also other solutions. On the connection between two parts of the roof on 90 degrees angle the mats had been placed on one another with an overlap of around 100 mm. Each mat had a size of 120 x 140 mm (see figure 38).

On the other side of the roof, due to esthetics reason, seaweed rule with the roofing felt underlay was covered from two sides by seaweed mats. In the gap between the mats dry eelgrass was placed and on top of it another seaweed mat was installed.

(Figure 39).

Workshop had experimental character and allowed thatchers to try the material in many different ways. All the work was managed by Henning Johansen and Bodil Pallesen. (www.agrotech.dk)

Figure 39: Ridge finish out of seaweed roll with seaweed mats on the sides and loose eelgrass in the middle. (Enclosure 4)

6.2. Neptune Balls

This type of seaweed is endemic to the Mediterranean Basin and it is used for insulation production by Neptutherm® in Germany.

Gathering Method

Seaweed is gathered manually in Albania and Tunisia. According to the manufacturer of Posidonia oceanica insulation in Tunisia work is carried out by large amount of women and it takes 7 full days for 30 women in order to load one full truck of seaweed. (www.neptutherm.com) Transportation Method

Loose seaweed is transported by either ship or train. Only in case of lack of other choice the trucks are used. (www.neptutherm.com) Production Method

The most important part of production is removing the adhesive sand form the seagrass, which is not easy at all. Additionally, individual fibers often catch on either each other or surrounding and quickly form new clumps during the process of production as well as while already blown into the construction.

However, There had been invented a way how to solve these problems.

According to Dr. Gudrun Gräbe form Fraunhofer Institute “Shaking the Neptune balls proved the best way of making sure we end up with fibers that are as long as possible and free of sand.” (www.cordis.europa.eu) That means that Neptune balls are shaken until all the sand is Figure 40: Neptune Balls (www.fraunhofer.de)

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removed and the fibers are acquired. The seagrass fibers are delivered to cutting mills, where they are cut in 1,5 – 2 cm pieces and packed into plastic bags. (www.cordis.europa.eu; www.neptutherm.com) Sustainability aspect

Neptune balls insulation is said to be really environmentally friendly product. The production process does not require much energy, since the seagrass is gathered manually and transported mostly by sea and road. That all makes Life Cycle Assessment looks really promising. The manufacturer claims that the production of Posidonia Oceanica insulation requires “up to 50 times less primary energy throughout the sourcing and manufacturing process” in comparison with conventional insulating materials such as grass, mineral wool, polystyrene or polyurethane foams and even wood fibers. (www.neptutherm.com) Additionally, according to eco-INSTITUTE in Cologne seaweed is 100 percent organic material entirely free of extraneous or toxic matter and it is said to be particularly suitable for allergy sufferers. (www.fraunhofer.de) Installation of the insulation

The insulation can be installed either by professionals or directly by the client. The difficulty level is said to be easy. The insulation can be filled into cavities in roof construction, ceilings and walls and afterwards packed tightly by hands. In case of hard to reach places the insulation is blown by a machine. (www.fraunhofer.de)

Figure 41: Installation of seaweed insulation produced by Neptutherm. (www.neptutherm.com)

6.3. Part conclusions

To sup up, even though both production methods seem really different form each other, some principles still stay the same. However, while Neptutherm stops at chopping pure seagrass into smaller fibers, Advance Nonwoven goes a step forward and owning to its unique CRAFT technology is able to create a consistent product similar to the one we know. These two different forms of the insulation bring different possibilities of usageone can be easier to work with in some cases, another in others. However, both materials are 100% natural, sustainable and really promising.

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7. Properties of seaweed

Even though the rich history of seaweed in building industry is pretty impressive, the biggest question is still unanswered. Obviously, if seaweed is supposed to be used as insulating material, it should also insulate and fulfill all the other demands insulating materials nowadays has to fulfil. However, since the material is not fully introduced to the market, it is impossible to define all the properties precisely. This chapter´s aim is therefore to gather all available data concerning most important seaweed properties and try to get the general overview.

7.1. Thermal conductivity

One of the most important values of insulation material is its ability to insulate. Therefore thermal conductivity is the property, this chapter will start form. Seaweed has really good insulating and heat holding capacity appreciated for centuries. According to Jørgen Søndermark “120 mm of seaweed insulation equals 100 mm of modern mineral wool insulation” (Realdania Byg, 2013, p. 53) Adding it to that the fact that seaweed is a natural, sustainable product, it creates a certain competitiveness of seaweed on the market of insulating materials. Especially, if the subject of comparison would be carbon dioxide footprint - then seaweed insulation has not many other materials to be compared to.

7.2. Acoustic properties

Together with good thermal insulating properties come exceptional sound insulating properties. Cabot`s Quilt produced in United Stated before second world war was advertised as “as efficient an insulator for sound-deadening as it is for heat and cold”.

(Cabot, 1928) That is probably why Radio City Music Hall in New York was insulated with Cabot’s Quilt Insulation at that time (www.seagrassli.org). Even though we cannot base on any nowadays scientific research, the opinions about seaweed houses are confirming the hypothesis. According to Jørgen Søndermark from Realdania Byg seaweed has “remarkable acoustic properties” and “this creates surprisingly comfortable rooms.” (www.dezeen.com) In other words, seaweed has a great potential not only as a heat insulator, but also as a sound insulator, which widens the possibilities of using seaweed in building industry in general.

7.3. Reaction to fire

If the seaweed is such a good thermal and sound insulator, can it also insulate against fire? This question is not that easy to answer. Nowadays a lot of attention is turned to security against fire; therefore material´s fire-redundant properties are valued really high.

Seaweed, owning to slat content, is considered to be a material that does not burn.

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However, even though many publications are expressing their amazement towards unique fire-redundant properties of the seaweed, we ought to be critical.

According to the small amateur experiment (Enclosure 7) Seaweed does burn, but the process of burning is really slow. Both seaweed and prototype of seaweed mat caught fire while exposed to the direct flame, although seaweed insulation mat resisted almost three times longer than loose seagrass. The burned particles carbonized and turned into ash, not causing any rapid fire spread. The process was comparable the process of burning wood.

The data available on Neptutherm`s website are mainly agreeing with the experiment`s result. According to these infromation the material with the salt content of 0,5-2% achieves DIN 4102 building material class B2, which is defined as normal flammability.

Wood is in the same fire category in this classification system. Unfortunately, the test is approved only in Germany, and no equivalent test had been carried out in order to define the fire Euroclass for Posidonia Oceanica. Before results of such test will be available, it is really hard to elaborate on fire resistance of Posidonia Oceanica according to Danish Law. (www.neptutherm.com; www.wikipedia.org) On the other hand, seagrass insulation mats made out of Zostera Marina, another type of seagrass, are still at the testing stage. According to the interview with Flemming Werk from Advance Nonwoven, the company tested the seaweed mats unofficially and the product was highly fire-redundant. (Enclosure 2) This information confirms Bodil Pallesen from AgroTech, who speculates, that the based on the result obtained from unofficial tests the company is looking forward fire class B. (Enclosure 3) 7.4. Lifespan and resistance to mold

Seaweed lifespan is doubtlessly its huge advantage compared to other materials. Looking at the examples form LÌsø Island in Denmark, such seaweed traditional roof can resist form 200 up to even 400 years. That should leave no doubts concerning material´s resistance to mold, since the roof thatching is not secured in any way against moisture.

However, the only species of seagrass tested concerning resistance to mold is Posidonia Oceanica produced in Germany. According to manufacturer`s webpage this type of seagrass insulation achieves mold resistance class 1, which is defined as top quality materials for medium to high production requirements and basically confirms the hypothesis of seaweed`s resistance to mold. The tests were carried out by Fraunhofer Institute in Germany and unfortunately no similar tests had been carried out on either Zostera Marina or Seaweed Insulation Mats. (www.neptutherm.com; www.teampti.com; www.naturalhomes.org)

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On the other hand, the lifespan of seaweed itself and the lifespan of seaweed insulation mat is a bit different case.

According to interview with Flemming Werk form Advance Nonwoven (Enclosure2) Seaweed mats life expectancy circulates around 20 years, after which the mat can be produced again form the remaining fibers. However, the tenyears-old-mat (Figure42) kept outside during all this time does not look on its age. Even though the mat got visibly compressed and some vegetation started growing on it, no signs of either mold or decay are visible. The mat is a possession of Bodil Pallesen form AgroTech and was presented on the seaweed workshop. (Enclosure 4)

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Figure 42: Old and new seaweed mat (Enclosure 4)

7.5. All the other virtues of seaweed

Seaweed is considered to be hygroscopic material, which can be a huge advantage concerning indoor climate. As Jørgen Søndermark from Realdania Byg says, hygroscopic abilities of seaweed „create surprisingly comfortable rooms, while the ability to absorb and give off moisture contributes to regulate the indoor climate." (www.dezeen.com) Adding to it the fact, that seaweed is a vermin-free, no toxic material, in few years we can expect the product, which can be highly competitive to the standard insulating materials.

(Realdania Byg, 2013) 7.6. Threats

Seaweed`s natural origins create also a certain boundaries. The reason of that is that nobody can predict what quantity of seaweed can be expected to be harvested. (www.tangtag.dk) Another limitation is the ecosystem of the sea, in which seaweed plays important role, and its excessive harvesting could deeply harm the environment. (www.seagrasswatch.org). Therefore we should be careful and use the resources we have wisely. “It is still a big challenge” Says Bodil Pallesen from AgroTech, and adds, that we know now too little about seaweed to determine its future “It will probably be used for special purposes – and it will not have to be produced in the way Rockwool is- so it is too early to answer this question” (Enclosure3).

7.7. Part conclusion

All in all, seagrass is a valuable material with a lot of potential. Owning to its various properties and really sustainable origins the material has a possibility of becoming really competitive on building market. However, in order to examine deeply its properties and find out whether the different species of seaweed really have different properties official

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tests have to be carried out. On the other hand, the amount of raw materials should be taken into consideration while thinking about seaweed insulation as a product produced on a big scale.

8. Conclusion

All in all, seaweed is fascinating material that has many possibilities for becoming important in the building industry. Its reach history had shown that seaweed insulation was not used as insulation just out of randomness, because the fact that we have evidence of usage of seagrass in many different parts of the word and in completely different times is already a huge proof of seagrass properties. Furthermore, though history we can examine different methods of gathering, threating and using seaweed and on this basis can be built modern production and construction methods.

The report proves also, that seaweed is not only material of the past existing exclusively on the pages of history books. The initiative taken on Danish Island LÌsø by Henning Johansen together with other members of seaweed triumvirate resulted in bringing seagrass back to life and turning the attention on this new material. I consequence Realdania Byg came up with the idea of building modern seaweed house which meant using the old material in modern ways. The project shown that seagrass, even though natural and not harmonized, can be integrated into beautiful architectural vision, and in addition fit in the economical frames and tight time schedule. Moreover, the house has negative carbon dioxide footprint and fulfills the requirements for low energy buildings in Denmark, which mean consuming no more than 20 KWh per meter squared per year and equals to Danish energy Frame 2020.

Consequently, the modern seaweed insulation appeared, in form of either loose fill or insulating mats. In both cases the material is fully natural, sustainable, and really promising.

Seagrass properties are also exceptional, although in many cases we have to base on somebody`s opinion rather that official tests. Furthermore, dividing seagrass into species turned out to be a necessity, since it is not known if their properties are the same, and comparing the only one known value, which is thermal conductivity, confirms that there is a difference between them. Unfortunately, it is only hypothesis, the same tests have to be carried out on both of the species in order to find out whether it is correct or not.

Besides that, seagrass have really good properties and can be competitive on the market owning to its natural origin and many other virtues. It`s thermal conductivity is comparable to mineral wool, and its fire class is expected to be class B. Furthermore, it insulates really well towards sound, is vermin-proof and mold proof, and its hygroscopic

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abilities are influencing the indoor climate positively. Moreover, the material is fully natural and sustainable, which and that matters a lot in nowadays building industry.

However, the fact that seagrass is a natural product of the sea has its pros and cons. In case of starting the production on bigger scale the problem may be the insufficient amount of raw material available, therefore the issue of producing seaweed insulation is actually more complicated than it seems.

All in all, many things we can say about seaweed, but for sure not that it is just a sea waste lying on the beaches. It is valuable, promising material, with huge possibilities in the modern, sustainable building industry of the future.

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Bibliography Books

Ehmann, S., Klanten , R., & Borges, S. (2014). Tegnestuen Vandkunsten. In Building Better: Sustainable Architecture for Family Homes. (pp. 148-153). Berlin: Gestalten.

Jensen, J. K. (2012). Tængemænd og vaskerpiger. København: People`s press.

Jensen, J. K. (2014). Naturens eget tag. København: People`s Press.

Moe, K. (2014). Insulating Modernism. Isolated and Non-isolated Thermodynamics in Architecture. Basel: Birkhauser.

Nienhuis, P. H. (2008). Environmental History of the Rhine-Meuse Delta: An ecological story on evolving human-environmental relations coping with climate change and sea-level rise. In P. H. Nienhuis. Springer Science & Business Media.

Pfundstein, M., Gellert, R., Spitzner, M. H., & Rudolphi, A. (2007). Insulation Materials.

Principles. Materials, Applications. Munich: Brikhäuser.

Realdania Byg. (2013). Den moderne tanghus på Læsø. Odense: OAB-Tryk a/s.

Articles

Cabot, S. (1928). Build Warm Houses with Cabot`s Quilt. Boston: Samuel Cabot Inc. Wylle-Echeverria, S., & Cox, P. A. (1999). The Seagrass (Zostera MArina [Zosteraceae]) Industry of Nova Scotia (1907-1960). Economic Botany 53 (4), 419-426.

Yang, J. (2012). Properties analysis of seaweed as a traditional building material. Trends in Building Materials Research (pp. 154-157). Hangzou: Trans Tech Publications, Switzerland.

Zhang, N. (2011). Idea on low-tech ecological evolution of seaweed house in Jiaodong Peninsula. Advanced Materials Research Vol. 243-249, 6961-6964.

Webpages

www.iucnredlist.org. Retrieved October 07, 2015, from http://www.iucnredlist.org/details/153538/0 www.iucnredlist.org. Retrieved October 07, 2015, from http://www.iucnredlist.org/details/153534/0 www.seagrasswatch.org. (n.d.). Retrieved August 25, 2015, from http://www.seagrasswatch.org/seagrass.html

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www.mesa.edu.au Retrieved October 20, 2015, from http://www.mesa.edu.au/seagrass/seagrass04.asp www.seagrassli.org. (n.d.). Retrieved August 19, 2015, from www.seagrassli.org: http://www.seagrassli.org/conservation/history.html www.usa.chinadaily.com. Retrieved September 20, 2015, from http://usa.chinadaily.com.cn/epaper/attachement/jpg/site1/20130117/f04da2db 112212618ceb21.jpg www.duskyswondersite.com. Retrieved September 20, 2015, from http://www.duskyswondersite.com/wp-content/uploads/2014/09/Seaweedhouses-Shandong-province-China.jpg www.china.org. Retrieved September 14, 2015, from www.china.org: http://www.china.org.cn/china/shandong/2012-06/15/content_25684613.htm www.chinadaily.com. Retrieved from www.chinadaily.com.cn/opinion//201505/26/content 21192830.htm www.tangtag.dk. Retrieved October 13, 2015, from www.tangtag.dk www.dezeen.com. Retrieved 08 25, 215, from www.dezeen.com: http://www.dezeen.com/2013/07/10/the-modern-seaweed-house-byvandkunsten-and-realdania/ www.bygningsreglementet.dk.. Retrieved October 16, 2015, from http://bygningsreglementet.dk/br10_05_id5182/0/42 www.neptutherm.com. Retrieved August 24, 2015, from www.neptutherm.com: http://www.neptutherm.com/index.php?home www.cordis.europa.eu. Retrieved October 07, 2015, from http://cordis.europa.eu/news/rcn/35568_en.html www.fraunhofer.de. Retrieved September 4, 2015, from https://www.fraunhofer.de/en/press/research-news/2013/march/seaweedunder-the-roof.html www.wikipedia.org. Retrieved 10 October, 2015, from https://en.wikipedia.org/wiki/Flammability www.tempati.com Retrieved 10 October, 2015, from http://www.teampti.com/Content/Pdf/SPI_Guidelines.pdf www.naturalhomes.org. (n.d.). Retrieved October 14, 2015, from http://naturalhomes.org/seaweed-house.htm?a=workshops

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www.agrotech.dk. Retrieved October 24, 2015, from http://agrotech.dk/arrangementer/arrangement/workshop-med-toerv-af-tang-tilstraatagets-rygning www.agrotech.dk. Retrieved October 24, 2015, from http://agrotech.dk/projekter/project/tang-toerv-til-straatage-nyudvikletlangtidsholdbar-tangmoenning-0

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Enclosures Enclosure 1

Cabot`s Quilt Insulation leaflet – construction solutions (Cabot, 1928)

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Enclosure 2

Flemming Werk, 2015, Interview with Flemming Werk from Advance Nonwoven A/S, Interviewed by Anna Katarzyna Plawecka [written] Advance Nonwoven A/S, Moellerupvej 26, 8410 Roende, Denmark, 19th October 2015 Interview with Flemming Werk form Advance Nonwoven A/S

My name is Anna Plawecka, I am a student of Construction Architecture and I am writing my dissertation about seaweed insulation. I have prepared some questions regarding seaweed insulation mats the company is producing.

•

How the company came up with the idea of producing mats out of seaweed?

-

The demand came actually from a thatcher form Læsø and Bodil Pallesen form AgroTech. They contacted us and asked if we could produce insulation mats made out of seaweed, so we gave it a try.

•

How long does company produce Seagrass Insulating Mats?

-

•

Around 1 year and only the fire test approval of the product from a notified body is yet to be settled. The approval is expected in max. 2 months.

Where do you buy the seaweed from?

-

•

From Bogø Island in Denmark.

Did you have any difficulties finding out seaweed properties? What researches did you base on?

-

We are still testing the material, but until now it seems to have really good properties, especially regarding sound and fire. We have tested the seaweed mats according to fire in our company and it did not burn, but now we are waiting for official tests to confirm it.

•

What about sustainability and carbon dioxide footprint? How much CO2 it is emitted to atmosphere while producing seaweed insulating mats?

-

I have no data regarding production process of the machines itself.

However, the machines do not pollute the atmosphere due to the Co2 filters we have installed.

•

How long is the lifespan of seaweed mats?

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•

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The same as any other product this type which means from 20 years and up.

Want happen when the life span ends? Can they be reused/ recycled?

-

They can go through the production process again and the process can be repeated many times until there will be no fibers to reuse and only dust will remain.

•

Can you explain me production process step by step?

-

The raw material first goes through hammer mill, and goes through a fiberizer and into storage boxes (hopper feeder and weighing system) and then the binder is added to the material mixed in “mixer”. After that the material is going through the patented CAFT technology machine which creates desired density and thickness of the mat. Then the mat goes to the oven where the heat is used to bond the fibers. In the end mat is cooled down, cut into required sizes, winded or stacked and packed, wrapped.

•

Do you use any additional additives to improve seaweed mats quality?

-

•

No, we only use binder in order to keep fibers together.

How much time it takes to produce one mat?

-

It does not take long, the single process of producing the mat takes around 25 minutes.

•

How expensive the production of the seaweed mat is?

-

The expenses depend on the market and price of the raw material. In case of waste material we can be really competitive to the market price. The production of seaweed did not start fully yet and I am not able to define how much it will cost.

•

Can you use the same machines and techniques as for other materials?

-

Yes, we can use the same machines for wide range for product; the only issue is cleaning the machines while changing from one material to another.

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How big the demand for Seaweed insulation is Mats? Ex. in comparison with other materials you produce.

-

I cannot answer this question, since the material is still at the testing stage not known in the market. Our estimate is that the market size could be app 30 mill. dkr. per year.

•

How many competitors on the market do you have?

-

There is no other company on the world using the same technique we are using.

•

Thank you for your time and help. Do you agree that I will use this interview in my dissertation?

Yes please do, Signed by

Flemming Werk Advance Nonwoven A/S

Photographs form the production process of seaweed insulating mats obtained from Advance Nonwoven:

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Enclosure 3

Bodil E. Pallesen, 2015, Interview with Bodil E Palleasen from AgroTech A/S, Interviewed

by Anna Katarzyna Plawecka [written], Kirkevænget 1, Feldballe, 8410 Roende, Denmark, 23rd October 2015 Interview with Bodil E. Pallesen from AgroTech A/S

My name is Anna Plawecka and I am student of Construction Architecture. I am writing my dissertation about seaweed insulation and I would like to ask you some questions.

•

How good, in your opinion, is seagrass as insulation material? o In the top

•

What about its lifespan? o

The construction- there is no borders. It is still possible to find really old houses , where seaweed/eelgrass was used as insulation material

•

Seagrass mats produced by Advance-Nonwoven A/S are quite new material. Do we already know lambda value, acoustic properties or fire classification of seagrass? o Lambda value comply with mineral wool one, but remember that it is just a prototype, and we are actually not ready with all the tests. We are expecting fire class B according to the temporary tests that we had carried out.

•

How easy in your opinion is work with seaweed on the building site? o With the right equipment there is no problems

•

Do you think that seagrass is expensive material in comparison to other, standard materials? o It will probably be used for special purposes – and it will not have to be produced in the way Rockwool is- so it is too early to answer this question.

•

What do you think about the future of seagrass in building industry? Do you think that it can become as popular as mineral wool or polystyrene?

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o Look at the answer above. It needs to be researched if the whole company should be established, which will just produce pure eelgrass •

In your opinion can it be problematic that demand for seagrass will be too high comparing to the number of raw material? o Yes and it requires that salvage of raw material will also be more rational than now. So it is still a big challenge.

•

Thank you for your time and help. Can I use this interview in my dissertation? o Yes, but remember to write a source, and that the project got the support from MUDP, environmental protection agency, and partners of the project are Advance Nonwoven and Henning Johansen form Læsø, and that I am product developer and project leader from Agro Tech.

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Enclosure 4

Workshop: ”peat” of seaweed used as ridge finish on straw thatched roof,2015, attended and reported by Anna Katarzyna Plawecka, Kirkevænget 1, Feldballe, 8410 Roende, Denmark, 23rd October 2015 Workshop: “peat” of seaweed used as ridge finish on straw thatched roof.

Basic data of the event:

Date:

23rd of October 2015

Place:

Kirkevænget 1, Feldballe, 8410 Roende, Denmark

Character of the event:

open to everybody interested

Project behind the workshop:

The workshop was a part of development project, which had started 1st of January 2015 and will finish 30th September 2016.

The project is carried out by the cooperation of Henning Johansen, Læsø´s Seaweed Bank, Advance Nonwoven and AgroTech, and supported by MUDP (Danish Environmental Technology and Demonstration Department under the Environmental Protection Agency.)

The aim of the project: Development of “peat-like” structure made out of eelgrass, which can replace the existing solutions for ridge finish of straw thatched roof and make the work of thatchers easier.

Description of the event:

The aim of the event was to experiment with the prototype of the new material for ridge finish for straw thatched roof. The prototype was a mat produced out of eelgrass by Advance Nonwoven. Event started with quick presentation of the product. The 10-years old seaweed mat was presented as a proof of long lifespan of the product. During the event all participants had a possibility to try to work with the material on actual straw roof and were able develop the best construction solution. The event was run by seaweed roof thatcher from Læsø Henning Johansen and Bodil Pallesen, product developer and project leader form AgroTech. (www.agrotech.dk)

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Enclosure 5

Seagrass: Zostera Marina Specification. (Pfundstein, Gellert, Spitzner, & Rudolphi, 2007)

Seagrass: Zostera Marina Specyfication:

Zostera Marina

Name:

Eelgrass

Habitat (chosen):

Denmark China United States Netherlands

Properties: Density

75 kg/m3

Thermal conductivity

0,043 – 0.050 W/mK

Reaction to fire

good, tests in progress

Acoustic properties

good, not officially tested

Mold resistance

good, not officially tested

Products: •

Seaweed insulating mats produced by Advanced Nonwoven A/S (testing stage)

•

Components to The Modern Seaweed House on Læsø

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Enclosure 6

Seagrass: Posidonia Oceanica Specification.

Seagrass: Posidonia Oceanica Specyfication:

Posidonia Oceanica

Name:

Neptune Balls Neptune Grass Mediterranean tapeweed

Habitat:

Mediterranean Sea (Endemic)

Properties: Density

65-75 kg/m3

Thermal conductivity

< 0,039 W/mK

Reaction to fire (according to DIN 4102)

B2 (normal flammability)

Acoustic properties

good, not officially tested

Heat storage capacity (c)

2,502 J/kgK

Mold resistance

class 1

Water holding capacity

1,6 – 3,4 kg/kg

Salinity (about)

0,5 – 2%

•

Products:

Insulation material produced by NeptuTherm® in Germany

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Enclosure 7

Amateur experiment: Exposing loose seaweed and seaweed insulation mats on fire. 2015.

Carried out by Anna Plawecka. 25th October 2015, Horsens, Denmark.

Samples:

Loose eelgrass sample Seaweed insulation mat 10 cm x 10 cm, density 80 kg/m3 Procedure:

Both samples were exposed to the direct fire contact one by one, and it was measured after what time the sample caught fire.

Process:

Sample 1 â&#x20AC;&#x201C; loose eelgrass Fire caught on the eelgrass after around 2-3 seconds Burning process was clam and did not provoke rapid fire spread. Burned pieces carbonized and turned into ash.

Sample 2 â&#x20AC;&#x201C; seaweed insulation mat 10 cm x 10 cm, density 80 kg/m3 Fire caught on the mat after around 7-9 seconds Burning process was clam and did not provoke rapid fire spread. Burned pieces carbonized and turned into ash.

The process of burning was slower in comparison with loose seaweed.

Conclusions:

Even though both samples caught fire quite fast, it took almost three times longer to for seaweed mat to start burning compared to loose eelgrass. Additionally, the process was rather slow and no rapid fire spread was observed, and again, the seaweed insulation mat was burning slower than loose eelgrass. The burned pieces carbonized and turned into ash.

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