Green roofs brochure

Arcadis Landscape architecture & Urban Design

The Netherlands, 2023

Arcadis landscape architecture & urban planning

We have been involved in highprofile projects as spatial designers for more than 70 years. What connects us throughout those years is our passion for the profession, the intrinsic motivation to collaborate and our imagination. At the same time, we are, each for ourselves, unique people with our own qualities and views. We cherish this diversity and see it as our strength.

We see the impact of a changing climate, that people continue to move to the city and are more mobile and that biodiversity is declining worldwide. We also see that ‘experience’ plays a major role in the economy and society. Finally, we see the importance of a healthy physical layout of our cities and villages, especially in light of the recent corona pandemic.

What do we do

Our experience with green roofs

We are landscape architects and urban designers with a wide variety of backgrounds. We look at green roofs in a unique way. For us they are not only places where people can enjoy themselves, but we also consider them as part of the ecosystem. They can reinforce ecosystems in an urban setting.

From the preliminary design to BIM modeling, 3D rendering, planting schemes and the technical design, we can take care of it in house. Successful roof gardens are created when the design team is involved from start to finish.

We therefore design and program for climate resilience, connection, experience and health. We do this in collaboration with local communities. We promote the inclusion of people and nature in our design processes. Using our project management system, we deliver quality within time and budget. In this way we create meaningful, future-proof places that are not only pleasing to the eye, but also touch the heart.

We have the experience and knowledge to make your roof garden a little paradise.

Urban scale concept

Construction detailing

Concept design

Maintenance planning

Design phases

Building supervision

ADVANTAGES OF GREEN ROOFS

Ecology

Residential water technology

Ecological compensation area

Creation of reference areas and species-rich habitats for the displaced flora and fauna in residential areas

Microclimate improvement

Compensating for temperature extremes, increasing humidity, improving dust retention

Rainwater retention

Green roofs with water retention system retain 80-99% of the annual precipitation on the roof

Economy

More living space

Valuable useful areas and roof gardens can be created on industrial, office and residential buildings

Relieving of the sewer system

The maximum drainage peaks during heavy rain are reduced by 50-100% compared to a non-green roof area

Cost savings with split precipitation water charges

Reducing precipitation water charges by 50-100%

Improvement of cityscape and landscape

Increased introduction of plants, green elements and green areas

Better living and working environment

Creating more usable private and public open spaces

Reduction of aircraft and street noise

Green roofs with vegetation help to reduce noise in large cities

Improvement in the urban climate

Fine dust and heavy metals are filtered out, implementation of fresh air lanes, cooling of the environment

Intro

Roofs serve a purpose beyond protecting the building structure and are integral in defining the character of individual buildings and entire city districts. As open resource areas, they offer socially responsible solutions to combat the loss of natural living space and mitigate problems such as stormwater management and urban heat island effect in densely populated cities.

The emergence of Green Roofs has extended the formal language of contemporary architecture, adding significance to the concept of “Roof Landscape.” Nature, which has been displaced by buildings and paved surfaces, is making a comeback as an attractive green element in residential, recreational, and working environments.

Ground sealing in urban areas has led to the loss of important soil functions such as water transport, contributing to an increase in flood risk during heavy rainfall.

The continued sealing of soil also results in the further heating up of inner cities during summer months, as evaporation cannot occur from sealed surfaces. To address these issues, green roofs are able to retain water, provide moisture for the air, and offer a new habitat for plants, animals, and people.

Sustainable Schouwburgplein, 2017-2020

Rotterdam, The Netherlands

Extensive green roof

Unutilized, natural green areas on roofs with low expenditure for installation and low maintenance.

Intensive green roof

Utilized and high quality garden areas on roofs with high expenditure for installation and care.

Retention blue roof

A blue roof is a flat roof or deck which is designed to provide controlled retention and drainage to the sewer or outfall system, as part of a Sustainable Urban Drainage System (SuDS) proposal.

Biosolar roof

Green roof integrated with solar panels or PV-system. The cumulation of the two combines increased biodiversity, renewable energy production and a total reduction of your energy usage.

Vegetation layer

Substrate for green roofs

Filter fleece

Drainage and storage board

Protection and storage fleece

Root protection membrane

Roof layers

Retention roof intensive Garden roof Public roof

Solar green roof

Economy roof

The simplest, easiest and cheapest solution for extensive roof gardening.

It is used with a minimum amount of substrate and ground cover sedums, and because of this, conditions such as wind load, watering and maintenance work must be taken into account.

1. Vegetation layer - Sedum, herbs, grasses

2. Substrate for green roofs

3. Filter fleece

4. Drainage and storage board

5. Protection and storage fleece

6. Roof layers with root protection membrane

mm

mm 25 mm

mm

Green roof drainage system

1. Edge trim

2. Pebbles

3. Inspection chamber

4. Roof drainage

Triodos bank, 2011-2019

Driebergen-Zeist, The Netherlands

Standard system structure

Sedum, herbs, grasses, possibly woody plants

Perks of Nature roof

More plant biodiversity can be implemented on this green roof system. Height of substrate and better capacity of drainage board give possibility to plant perennials, grasses, lawn and small bushes.

• Ecologically valuable green roofing

• Can be implemented as a biodiversity space

• High evaporation capacity

• Long-lasting and colorful flowering aspect

• Accomodates a wide range of plants and animals

1. Vegetation layer - Sedum, herbs, grasses, possibly woody plants

2. Substrate for green roofs

3. Filter fleece

4. Drainage and storage board

5. Protection and storage fleece

6. Roof layers with root protection membrane

mm

Sustainable Schouwburgplein, 2017-2020

Rotterdam, The Netherlands

Biodiversity of green roofs

Roof greening plays a big ecological role in providing shelters and homes for plants and animals. The presence of diverse types of green roofs helps to offset the adverse impacts of land development and surface sealing. Furthermore, green roofs that feature varied vegetation types and promote biodiversity offer additional benefits such as retention of rainwater, slowing of water flow, cooling effects, and filtration of pollutants.

• Water

Permanent and seasonal bodies of water offer a sustained source of water for animals.

• Substrate

By incorporating various substrate heights and design elements, it is possible to create a green roof that is both aesthetically pleasing and ecologically significant. The use of substrate mounds, shrubs, and deeper substrate areas can provide frost-free habitats for soil-dwelling creatures. Additionally, selecting plants based on their blossom color

and flowering period can ensure the availability of food throughout the year.

• Deadwood

Many birds and insects find nesting and breeding habitats in sawn wood, including tree branches and trunks, decayed logs, and brushwood of varying thicknesses.

• Nesting aids

Providing wind-resistant nesting resources such as birdhouses, insect hotels, or beehives can assist animals in utilizing the roof as a long-term habitat.

GARDEN ROOF

Standard system structure

This is an intensive green roof with possibilities for lawns, bushes and trees and also can be combined with various design elements, such as ponds, pergolas, pathways and playgrounds. An underground car park can be integrated into surrounding outdoor facilities.

The result is a varied roof landscape with terraces, gardens or even kitchen gardens with urban gardening. So you can create rooftop landscapes that look like green areas on the ground.

1. Vegetation layer - Perennials, woody plants, trees

2. Intensive substrate

3. Aeration substrate

4. Filter fleece

5. Drainage and storage board

6. Protection and storage fleece

7. Roof layers with root protection membrane

Wonderwoods Towers Gardens, 2017-2023

World Trade Center, 2020-2023

Utrecht, The Netherlands

Amsterdam, The Netherlands

Sedum, herbs, grasses, possibly woody plants

shrubs, lawns, trees

Standard system structure - extensive

1. Vegetation layer - Sedum, herbs, grasses

2. Substrate for green roofs

3. Filter fleece

4. Water retention box

5. Protection and storage fleece

6. Roof layers with root protection membrane

Standard system structure - intensive

1. Vegetation layer - Perennials, shrubs, lawns, trees

2. Substrate for green roofs

3. Filter fleece

4. Water retention box

5. Protection and storage fleece

6. Roof layers with root protection membrane

Smart Blue Roof

In regions where it rains frequently, a blue roof solution can replace all previous green roof solutions. The possibility of saving on taxes and on concrete roofing, reuse of accumulated water, reducing the load on the city’s storm system often offset the costs of the high cost of materials during installation.

There is also the possibility of creating a Smart Blue Roofthere are technologies that allow you to control the amount of rainwater accumulation using your phone.

Water retention box

Stores

1. Basic state - rainwater is stores and made available to plants during dry perions: plant water supply, evaporative cooling.

2. When the forecast predicts rainfall, a special app on your phone promts the Smart Flow Control to open the drainage outlet and release the amount of stored water. After that it automatically closes the drainage outlet.

3. Precipitation is stored in the Water Retention Box. No water is drained into the sewage system. So the max possible amount of rain is saved.

up to 160 liters of water per sq. m.

PUBLIC ROOF

Rooftops and roofs of underground parking lots, that are situated at ground level, can provide walkways for people and passages for cars and fire engines. The design of these spaces should take into account the load capacity of the roof, and different combinations of layers can be used to achieve optimal conditions for your specific design needs.

World

1.1.

1.2.

1.3.

1.4.

1.5.

1.6.

2.1. Pavement

2.2.

2.3.

2.4.

2.5.

Vegetation layer - Sedum, herbs, grasses

Substrate for green roofs

Filter fleece

Drainage and storage board

Protection and storage fleece

Roof layers with root protection membrane

Suitable stone chippings

Base layer of gravel 0-22mm, 0-32mm, 0-45mm

Protection and drainage board

Protection, separation and slip layer

Concrete border

Connection of the green area with paving (lorry or fire engine up to 20 t)

Trade Center, 2020-2023

Amsterdam, The Netherlands

Amsterdamse Poort

images by Paul de Ruiter architects

Amsterdam, The Netherlands

SOLAR GREEN ROOF

Solar panels

Green roofs and solar systems can be combined, especially on flat roofs. The effects of synergy occurs in generating electricity, because the low surface temperature of the greenery, compared to weathered or gravelly roofs, leads to a lower heating of the photovoltaic modules and thus to increased efficiency.

Vegetation

When planning photovoltaic systems, it must be ensured that the modules are not shaded by the vegetation. For this purpose, attention must be paid to a sufficient distance of the lower edge of the modules to the substrate, depending on the height of the vegetation. The minimum distance for a low-growing extensive greening should be 20 cm.

Solar energy

Different conditions exist on the roof due to different solar radiation and moisture conditions. In order to obtain sufficient light incidence, even from diffused light, the distance of the module rows, the module depth, the height of the modules or the transparency of the module rows must be adapted to the vegetation.

Property-related spacing

South-facing orientation with 15° incline

East-west orientation with 15° incline

PITCHED GREEN ROOF

Roof pitch/fall

Pitched Green Roofs above a 5 degree slope are considered to have a pitch, which may affect the design. Most vegetation will grow on quite severe slopes, but the designer must consider the practicalities of installing the green roof, and just as importantly, how the roof is to be maintained.

Two factors are particularly important and need to be considered with regards to pitched green roofs: a reliable and permanently functioning anti-slip system and fast-rooting vegetation in the form of precultivated mats to help prevent erosion.

Vegetation

Different types of vegetation are possible, depending on its height and type of structure.

For thin-layered pitched green roofs is recommended to use drought-resistant plants such as sedum.

Maintenance

The amount of maintenance required depends on the plant species selected. Depending on the vegetation, the roof should be given fertiliser every year to provide the plants with the nutrients they need.

Depending on the type of roof slope, different methods of fastening and holding the substrate from slipping are used.

Embracing water

Vitalizing cities

Connecting people

Stationsgebied Driebergen-Zeist

Enriching identities

Regenerating landscapes

Waterfront Guhawati, India

Naardereiland

Landgoed hoofdkantoor Triodosbank i.s.m. RAU architecten

Duurzaam Schouwburgplein, Rotterdam

Essenler Park, Istanbul

Toekomstperspectief Raamvallei

Dairy Campus, Leeuwarden

Maashorst Ontwikkelperspectief

Stationsgebied Roermond

Knooppunt Hoevelaken

Baakse Beek Medler

Zuidpolderpark Barendrecht

Zeesluis Terneuzen

Wonderwoods, Utrecht i.s.m. Boeri architectti & MVSA architects

About Arcadis

Arcadis is the leading global design and consultancy organization in the field of the natural and built environment. Applying our deep market sector knowledge combined with design, consultancy, emgineering, project and management services, we work with our clients to deliver exceptional and sustainable results.

www.landscape-architects.nl

Disclaimer

While every effort has been made to ensure the accuracy of the material contained in this document, Arcadis is not liable for any loss or damage incurred through this use of the report.

Authorship

This report has been prepared by Arcadis Nederland BV. The opinions expressed herein are those of the authors and are based on their practice and combined with data from external sources.

John Boon

Head of Advisery Group and Urban Design, Arcadis Netherlands

E-mail: john.boon@arcadis.com

Wouter Veugelers

Landscape designer, Green roof specialist

E-mail: wouter.veugelers@arcadis.com