Why Do Flat Roofs Have Rocks On Them

A flat roof is a roof which is almost level in contrast to the many types of sloped roofs the slope of a roof is properly known as its pitch and flat roofs have up to approximately 10.

Why do flat roofs have rocks on them. Ideally the stones are river gravel which has smooth edges and won t cut into the roof when somebody walks around on it. The gravel provides a better grip for foot traffic when conducting maintenance or repairs. Talk to ten roofing contractors and you ll get ten answers on what the gravel is for but this seems to be the consensus. Rocks are placed on commercial flat roofs for many different reasons.

Because the gravel holds and releases heat the layer of gravel on a bur flat roof can both help water evaporate and keep heat away from the underlying roof structure. Roofing ballast is usually the little pebbles you see on a flat ish roof. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof flat roofs or low slope roofs are also commonly found on commercial. This is for a roofing membrane that is not fully adhered to substrate and the pebbles are essentially acting as a paperweight.

But such a low slope holds snow and water much longer than a steeply pitched roof and therefore needs a very different material to stay watertight. It has a very low slope between 1 4 to 1 2 inch per foot so that it drains water.