A ballasted or protected roof implies that the roofing membrane is not fixed nor adhered to the roof structure. The membrane is loose-laid and covered with gravel, paving slabs, substrate etc…
Obviously, the ballast offers a good protection against wind uplift. It also protects the membrane against direct stress caused by temperature fluctuations, punctures, tears, etc. but also against ageing, as the membrane is not exposed to UV radiation.
Thanks to the glass fleece reinforcing, the RENOLIT ALKORPLAN L membrane has an excellent dimensional stability.
A simple and fast installation without glue or fasteners and regardless of weather conditions, is undoubtedly an advantage. The seams are hot air welded at the overlap with either manual or automatic welding equipment.
The ballasted system is suitable for warm or inverted roof constructions, on both new build and refurbishment projects. Although it is most commonly used on a concrete support, steel deck and wood structures are perfectly possible as well.
Be aware that protected roofs require a roof structure that supports the additional weight of the ballast!
Green roofs are an ecological example of this system, thanks to the membrane’s root resistance. Apart from being environmentally friendly and energy saving, a ballasted system with plants or pebbles also offers an aesthetically pleasing and recreational advantage!
By the end of the roof’s lifespan, the membrane can be totally recycled.