One thing that is overlooked when green roofs are installed is the quality of the waterproofing membrane that is being used.
Well it wasn’t too many years ago people were using pond liners made from butyl, but it soon became apparent that sunlight made the butyl perish quite quickly. There is also the problem of unwanted plant species that can get onto the roof over time and attack weak points, especially the joints of a membrane. Some grasses and weeds, for example Ryegrass, are so aggressive that in tests and real life scenarios have proven aggressive enough that normal felt joints, heat welded joints and even strong multi beaded mastic joints just aren’t strong enough to repel some root systems.
They are both BBA certified to last 25 years and in real life, as with other EPDM systems, are known to last in excess of 50 to 70 years.
Another benefit of using the HERTALAN and PRO-EPDM sheets is that they can be made to suit your roof, this is done by vulcanising the joints of the sheets to the shape and size you need. And it’s not just squares or rectangles, we can manufacture sheets for curved buildings, an example of this will soon be airing on George Clarke’s amazing spaces.
If any jointing is required where you can’t install the membrane in one sheet, there is a special cover strip which has been designed for green roofing which uses a hot air welding gun.
When using HERTALAN and PRO-EPDM with green roofs, the sheet can be loose laid making the whole structure watertight very quickly. Some simple gluing at the edges and some detailing work will see the waterproofing layer finished very quickly so you can get on with laying down the other essential parts of your new green roof.