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THE big Rammed

Earth

Manual DIY build from as little as ÂŁ45 per m2 ($65 â‚Ź60) Learn the tips and tricks and avoid costly mistakes Over 270 photos and illustrations Get a three month head start on your project UPDATED FOR

2016 Michael Thompson

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

Special acknowledgements to everyone that helped with this project

Bridget Elahcene • photographer in charge and chief earth mixer Pebbles Thompson • solutions consultant Matthew Hill • all round muscle machine and ski instructor Philip Thompson • roofing consultant and general building expert David Thompson • electrical, plumbing and portholes Graham Colk • ground management and fitness mentor Chris Harrould • construction advisor

Michael Janzen • Thompson MKIII Former illustrations David Beasley • SID illustrations Dusty Gedge • green roof expert

ECO-SHED ...one planet to the max! Details of publications from the Eco-Shed are available at: www.rammed-earth.org Requests to copy any part of this publication must be made to: Michael Thompson - email: rammed-earth@hotmail.co.uk Tel: +44 (0) 7768 772366 Copyright © 2012 Michael Thompson. Unless otherwise stated. First published March 2010 Updated July 2012 Updated November 2015

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

CONTENTS FOREWORD

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INTRODUCTION

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A BRIEF HISTORY

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USE OF RAMMED EARTH

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TOOLS OF THE TRADE

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IN THE BEGINNING, THERE WAS SID

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FORMER DESIGN

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FOUNDATIONS

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SOIL TESTING

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GROUNDWORKS AND FOOTINGS

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EARTH PREPARATION

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FORMER CONSTRUCTION

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SOILS FOR RAMMED EARTH

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SOIL MIXING

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RAMMING EARTH

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RELEASING FORMERS

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VDB – VOLUME DISPLACEMENT BOX

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LINTELS

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WINDOW SILLS

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WINDOWS

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THRESHOLDS

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DOORS

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PORTHOLES

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BOND BEAMS

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GREEN ROOF STRUCTURE

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HOW THE PROFESSIONALS DO IT

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CONCLUSION

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

good thermal mass, which helps keep indoor temperatures stable, particularly in regions with dramatic daily temperature changes. The half-day rate of heat transfer and thermal mass of the material makes rammed earth a particularly suitable material for passive solar buildings. Rammed earth has been a popular choice for buildings where temperature fluctuations need to be kept to a minimum. It can be used in wetter climates but must be protected from heavy rain by an overhanging roof. Typically, rammed earth walls are about 300 to 360mm thick, making them ideal for humidity control and noise barriers from traffic, furnaces, compressors, fans or ducts. Rammed earth also allows more air exchange than concrete structures, as the material mass allows the building to breathe, avoiding condensation issues without significant heat loss. By its very nature, earth is one of the best sustainable building materials as historically it is the longest used material by man. It is a universally and naturally available product, with a heavy thermal mass and acts as a natural barrier to cold winds and forces of nature, including insects and rodents. The material is not rationed or monopolised, is fire proof and sound proof. Rammed earth housing has been shown to help resolve problems with homelessness caused by otherwise high building costs, as well as to help address the ecological dilemma of deforestation and toxic building materials associated with conventional construction methods. In recent years, rammed earth has become popular amongst environmentally conscious architects as well as those seeking an element of exoticism.

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

TOOLS OF THE TRADE Mixing You will need some type of mixing machine; I used a regular cement mixer, which I bought second hand for around £100. These mixers can handle nine shovels of earth at a time. This is a good quantity for ramming by hand; it takes around 15 to 20 minutes to get the earth to a suitable dampness. It also takes around the same amount of time to ram this quantity by hand, so if you have a two-person team you will be working to the maximum efficiency.

You could use a rotovator instead, if you have the floor area to operate it. These are handy if you need to mix bigger volumes of earth. If you plan to use pneumatic ramming then you may well need to get one of these, as mechanical ramming can be up to ten times quicker than manual ramming. Second hand rotovators can be picked up for around £100.

Water When the earth is processed, it usually requires the addition of water which should be blended slowly and evenly throughout the mix. If you plan to use rainwater then you will need to use a watering can with a sprinkler rose, if you use mains water then get a hosepipe gun with a sprinkler setting.

Material handling Do not underestimate the power of the rubber bucket! You will need to transport your materials around the build site and they are invaluable in the rammed earth construction process. They cost around £4 but last a long time. You will need about six of them. Wheelbarrows are also invaluable. You may well already have one knocking around but you will need at least two. They are quite expensive at around £35, but most people have one that they rarely use, so ask your friends and neighbours if you can borrow theirs.

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

Raft Raft foundations cover an area at least the same size as the base of the building. They are used on soft compressible subsoil such as soft clay or peat. However, it is important that they are reinforced to resist the effect of ground movement and the raft should be constructed with an apron edge so that it doesn’t slide.

Pile Pile foundations are used to support buildings in subsoil conditions such as on shrinkable clays, infill or waste tips, slopes and sites with a high water table in a poorly drained region. They are a substitute where conventional foundations would need to be so deep that they would be uneconomical. In effect, a basic pile foundation is a series of stilts or columns that rest on a solid, load-bearing layer of the soil up to four metres below the surface. Beyond this depth, the expense usually becomes prohibitive for small build projects although there are self-builders that have completed a project to budget with piles going down ten metres. The piles may either be precast or cast in-situ.

Eco-Shed strip footings with stem-wall nearly ready for earth ramming

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DESIGNING THE ECO-SHED The walls of the Eco-Shed were constructed as shown in this basic diagram.

This seemed straightforward enough so I thought I would spice things up a little by designing a five sided building of which one wall was curved. Probably not the first thing that springs to most peoples’ minds, but the design lends itself to the way our garden is set out. Also, a curved design makes the building appear visually smaller, which is a useful trick to use when you want maximum space within your structure with minimum impact outside.

I made a 1:50 scale model of the Eco-Shed out of balsa wood which I strongly recommend you do too, as it can highlight areas where you may encounter problems with your build. As a result of my model, I decided to build the Eco-Shed one metre wider and slightly changed the roof construction.

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DIY Rammed Earth eManual 2016 edition Copy requested by – ISSUU NOV 15

By putting in a wide footing, it gave us some flexibility for positioning the actual building.

It takes a while to get it all levelled up. Note the curved excavation to the right of this picture. I guessed-i-mated its position whilst I had the digger and will do this curved footing once all the straight footings are completed.

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EARTH PREPARATION

I got 26 tonnes of subsoil from the footing excavation but I had calculated that I was going to need 39 tonnes. I knew this by working out the volume of my walls and multiplying that figure by 1.75 L x H x W = your wall volume x 1.75 = tonnes of earth required.

I made a few calls and found out that I could help myself to as much subsoil as I wanted from a new scout hut site six miles away. I paid ÂŁ100 for a grab lorry to collect the 13 tonnes I needed.

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Use varnish to seal the inside of your formers, this will give your walls a smooth surface.

Screw the former faces to the ribs and fill over the screw heads. Here I am assembling my curved former for the front wall, using my body weight to hold the curve whilst fixing it to the ribs.

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Only the corner formers have to be disassembled at each level of ramming. Note the keylock end panel still in place. This will be removed after the former sides have been taken off.

Use a spare piece of 15mm spacer pipe to gently tap out the pipe in the wall section.

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Ensure that any VDB you erect can be taken apart after you have completed ramming your walls. If the walls were rammed mechanically then you will need to beef up these openings with a timber structure to avoid them collapsing.

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The VDB for a window opening being positioned inside the former.

Again, the former is screwed onto the window VDB opening, to avoid bulging.

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After a quick going over with a wire brush, the lintel is ready for installation...

...and temporarily positioned on the window VDB.

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WINDOWS

To make the window frames, I used the timber left over from making the lintels. Painting them prior to installation makes life a lot easier.

I got my local glass shop to make me up some sealed units for about ÂŁ15 each.

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PORTHOLES

To create the porthole window, my brother and I made up a three-piece VDB which would be screwed together and placed inside the former. The circles were cut by spinning the router on a plank fixed by a screw to the workbench.

Then we packed them out with scrap plywood and skinned them with 4mm MDF to make them easier to remove from the wall once rammed.

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Once finished it was time to make a window frame for the porthole.

I machined up a series of hoops from plywood, which I could laminate together to make up the circular frame.

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A corner section showing the bond beam released from the former 24 hours later.

All the walls and bond beams finished and ready to receive the roof. This bond beam is 100mm thick and has a five degree slope.

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As a rule, the roof should overhang the rammed earth walls by one third of the height of the building in order to protect the walls from excessive exposure to rainfall. The EcoShed is three metres high, so I should have an overhang of one metre; however, I felt it wouldn’t suit the design of the building, so I reduced it to 400mm. I’m hoping that because Norfolk has the lowest annual rainfall in the UK that I will get away with it. According to the information in Dusty’s guide, we had to get the roof to look something like this. I changed this design slightly by reversing components 10 and 4 to give my roof a sleeker appearance. 1. Fit Joists 2. Fix Roof Deck 3. Fix ‘Arris Rail’ 4. Fascia 5. 75mm Spacer 6. Drill Outlet(s) 7. Lower Geotextile Layer 8. Waterproof Liner 9. Upper Geotextile Layer 10. Capping 11. Top Cap 12. Drainage

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Tower formwork enables whole wall sections to be rammed in one go. The rebar reinforcement carries all the way to the top of the wall and into the 100mm concrete cap.

Rigid insulation boards are rammed in place.

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CONCLUSION “So, what did I learn on this journey? A lot. I learnt that old methods doesn’t mean bad methods; that you don’t have to be a hippy to construct a green building and that you will eventually get used to your friends and family referring to your efforts as a “mud hut”! You will, in the end, have the last laugh... I did! I started this project as an eco-nomical build, but I finished it as an eco-logical build. I didn’t intend for this to happen, it just seems to be the case that when you build on the cheap, you end up using and reusing materials that have a low or already spent carbon footprint. Once I realised that there is no need to use expensive modern materials to build a modern structure, I managed to bring the cost of my building down much lower than I had expected. I achieved a 60 square metre building for just £2,700 in materials - the floor, walls, roof, doors and windows... everything, for just £45 per square metre. However - the biggest realisation was this... If I had used regular bricks for my project, the equivalent carbon emissions would be the same as if I had driven my car for 40,000 kilometres (that’s once around the world), whereas building with rammed earth (even using cement as a stabiliser), the carbon footprint of my walls equates to a journey of a mere 550 kilometres. That’s the difference between fired bricks and unfired earth! Building with rammed earth brings housing and home ownership back within the reach of just about everyone and could potentially be an effective solution to homelessness. That has to be good news for the estimated one thousand million people on our planet who don’t have adequate shelter. I’m not going to tell you it was easy but it was well worth all the hard work!”

Keep up to date with new content, pictures and videos at: www.rammed-earth.org

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DIY Rammed Earth Manual This manual has been compiled to accompany the rammed earth courses that run at the Eco-Shed in the heart of the Norfolk Broads, England. However, for those who are unable to attend a course but still wish to expand their knowledge and understanding of the rammed earth process, this will be an invaluable resource. Course testimonials: "This course is suitable for people with or without a technical background. The rammed earth theory combined with the hands-on approach enables anyone to complete the course with the confidence to start a rammed earth project. Michael's enthusiasm is infectious, he sees only challenges, not problems. This course will motivate you to get stuck in and give it a go and to top it all, the food is outstanding. If you do one course this year, make it this one!" Steve and Leyla - London

"The workshop was great! I can't wait to follow your example and start building my house... I will spread the word about your workshop." Célia - Portugals

Michael Thompson has been studying and working with rammed earth since he accidentally stumbled across it one winter’s evening in 2007... Soon after, he started building his own structures as detailed within this manual and runs DIY rammed earth courses from his award winning Eco-Shed in Norfolk, England. In addition, courses are occasionally held at other locations, see www.rammed-earth.org for more details.

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The BIG rammed earth manual  

“So, what did I learn on this journey? A lot. I learnt that old methods doesn’t mean bad methods; that you don’t have to be a hippy to const...

The BIG rammed earth manual  

“So, what did I learn on this journey? A lot. I learnt that old methods doesn’t mean bad methods; that you don’t have to be a hippy to const...

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