Green Roofs

Why a Green Roof?

Green roofs are widely recognised as an ideal way of improving air quality in cities. Planners and Councils are beginning to use extensive plantation for air purification in order to reduce carbon dioxide and increase oxygen in the atmosphere. Green roofs also make a significant contribution to reducing polluting air particles and compounds not only through the plants themselves, but also through the growing medium.

They are also increasingly being used in efforts to reduce and delay water run-off during times of heavy and prolonged rain, a fact that can be significant in reducing localised flooding. A recent study in Germany showed that during a 10mm rainstorm, whilst 200 litres of rainwater fell onto an 18m2green roof, only 15 litres actually passed from the roof to the ground. But given that some water does escape, it’s important to ensure that the waterproofing membrane does not have an adverse effect on the quality of water which is released from a green roof after rainfall.

When waterproofing green roofs the membrane itself must also be taken into account when thinking about the overall environmental picture. The method of manufacture, component chemicals and long-term environmental impact of the membrane itself can be as significant as the benefits of a bio-diverse ‘green’ roof.

A green roof requires a strong, durable and light membrane to line it. GRP (Glass Reinforced Polyester) is an inert material that can be used with ‘grey’ water harvesting systems and potable water. In service, it does not release any pollutants or chemicals.

Green roofs offer exceptional environmental and cost benefits to other forms of roofing, thus is becoming a mainstream option for commercial and domestic builds.

Why use Dryseal for waterproofing green roofs?

Dryseal GRP is environmentally sound, leaving no residual chemicals after installation and is ideal to waterproof a “living” roof.

  • Because Dryseal GRP is safe to use with fresh drinking water it is naturally ideal for use under a green roof.
  • The unique way that the Dryseal system is jointed on site means that there is a permanent chemical “cross-link” between the site applied jointing resin and the resin used in product manufacture.
  • As Dryseal joints are robust and permanent, this removes the need for the addition of a root barrier.
  • The high impact resistance and resilience of Dryseal mean that the chances of damage by others during a green roof installation are much reduced.
  • Dryseal comes with an installed 20 year ‘leak free’ guarantee.

Green Roof Partner

As Members of Green Roof Organisation (GRO) we work in co-operation with GRO.

GRO is an independent not-for-profit Trade Association representing the UK Green, Blue and BioSolar Roofing industries.

If you want to hear more about using Dryseal for waterproofing green roofs and green roof design in general, please download the GRO Code of Practice.

Alternatively for more information about the Green Roofing Organisation please visit their website directly.

Want to learn more about Dryseal?

Get in touch with one of our team members by emailing or call +44(0)1327 701 900


Dryseal can only be installed by approved contractors. Click on the link to find one near you.


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Hambleside Danelaw Ltd, Long March, Daventry, Northamptonshire, NN11 4NR