Green/Living Roofs

Waterproofing Systems - Wood Preservation & Damp Proof Systems picture

Waterproofing Systems - Wood Preservation & Damp Proof Systems picture
DE25 drainage and water storage membrane in sedum roof construction
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Green roofs deliver many benefits - particularly to urban areas. They insulate and protect roofing materials; clean the air and counteract climate change; provide microclimates for insects and bird life and create fabulous new spaces for work and leisure. Green roofs have existed in Scandinavia and other parts of the world for centuries, but an increasing desire to make a positive contribution to our environment and the development of modern multi-layered systems means we are witnessing a growing trend for their construction in the UK. A variety of imaginative and inspirational green roofs already exist across the country which vary from simple Sedum layers on single story extensions to areas of green lawn disguising the roof of an underground car park, wild flower gardens on the roofs of inner city estates and 'corporate' oases in Canary Wharf.

English Nature, in its publication entitled: "Living Roofs", identifies three basic types of types of living roof:

  1. Intensive - a layer of soil (1000mm plus) in which a variety of plants and trees are grown. These roofs are often used for recreational purposes and require frequent maintenance as well as placing significant loading on the building structure.
  2. Extensive - these are generally formed from a shallow layer (25 - 100mm) of substrate planted with a low growing moss or alpine species such as Sedum. They are lightweight systems and require little or no maintenance.
  3. Semi-extensive - a slightly greater depth of substrate than extensive (100 - 200 mm) these allow a greater diversity of plants to be grown, but are based on the same principles as extensive roofs and are medium-light weight and relatively low maintenance.

Green roofs can be grown on any pitch of roof, even vertical walls, however those with a pitch of more than 9.5° generally have specific design requirements in order to retain the water and substrate across the surface. (see section on Pitched Turf Roofs).


Components of a green roof

Construction involves a series of functioning layers which, while retaining the necessary water to support the plants, allow excess water to drain off and protect the roof surface from plant roofs and mechanical damage.

A typical extensive system would include the following:

  1. Vegetation layer - (plants)
  2. Lightweight soil 50-100mm in depth
  3. Filter mat
  4. Drainage layer (such as Isola Platon DE 25 membrane, supplied by Triton. This membrane has a special 23mm deep stud design which combines drainage and water storage to maintain long term roof planting.)
  5. Root barrier
  6. Waterproof membrane

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One of the largest green roofs in Spain, 54,000 M2, covers the parking area at Barajas Airport in Madrid. The roof incorporates Isola DE25 drainage and water storage system.

Platon DE25/DE40

Platon DE25 and DE40 membranes are designed for the construction of flat green areas on top of buildings and underground structures such as car parks and garages. They are laid between the waterproofing and soil layer. Their stud design provides an excellent function that combines drainage and water storage as one efficient system.

Installation: The individual sheets are overlapped by one row of studs, and covered by a filter fabric so the soil does not obstruct the water storage or drainage layers. Soil is spread out over the filter fabric, and the vegetation can then be planted.

Platon DE40 is designed for installation where high capacity water storage is required.


Platon DE25
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Platon DE40/500
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DE25/D40 Data Sheet
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DE25 Case Study
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Platon DE25 CE Marking Certificate
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Platon Xtra

Platon Xtra has been used in pitched turf roof constructions for over 20 years. Aging tests indicate that the Platon membrane has an expected life of at least 50 years. The Platon membrane, the main component in the system, is manufactured from HDPE, a material that is water repellent and resistant to chemicals. The Platon membrane combined with other components, creates a complete Earth Covered Roof System.

Supplied in 2.07 x 20m rolls.

NBS Plus Product Entry
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Platon Xtra Installation Guide
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Platon Xtra CE Marking Certificate
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RIBA Approved CPD Seminar

Triton offers a RIBA approved CPD seminar entitled 'Living/Green Roofs'. The seminar focuses on the installation of green roofs to structures, the benefits to be gained, the design principles and construction processes and further considerations. To book this seminar please visit the RIBA CPD seminar page on this website.

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  1. Green Roofs - Environmental and Cost Benefits Summary - PDF 856K
  2. Isola Platon DE25 Data Sheet - PDF 264K
  3. System Platon Membranes for Horizontal External Constructions Brochure - PDF 442K
  4. Sedum Roof Build-up Overview Data Sheet - PDF 92K
  5. System Platon Xtra - Installation Instructions, Basement Walls, Turf Roofs - PDF 702K
  6. 'English Nature - Living Roofs' - PDF 2.75Mb
  7. 'English Nature - Green Roofs, their existing status and potential for conserving biodiversity in urban areas' - PDF 779K
  8. The Platon Cavity Drain System Installation Guide (Complete Installation Manual) - PDF 3Mb
  9. Filter Fleece and Separation Layer data sheet - PDF 347K
Useful Links
  1. Technical Drawings
  2. RIBA approved CPD seminar 'Living/Green Roofs'
  3. NBS Specification Clause for Platon DE25
  4. NAP site case study
  5. www.livingroofs.org an independent UK resource for green roof information
  6. www.english-nature.org.uk
  7. www.igra-world.com a global networking site on green roofs