Why Do They Put Rocks On Flat Roofs

Specifically there are two main reasons to use a ballasted roof system.

Why do they put rocks on flat roofs.

Because the gravel holds and releases heat the layer of gravel on a bur flat roof can both help water evaporate and. The stones keep the tar paper in place and prevent it from buckling or blowing away in a high wind. My regards to mom. The gravel prevents sun hail errant baseballs etc from damaging the membrane the all important moisture seal created by the tar paper and tar.

They can be partially loose laid and held down with river rock ballast requires roof structure to support the weight or fully adhered to the roof deck. These small stones are worth more than their weight in the protection they offer for underlying roofing materials and the barrier they provide to external elements like ultraviolet rays and harsh weather elements. The gravel provides a better grip for foot traffic when conducting maintenance or repairs. Roofing ballast is usually the little pebbles you see on a flat ish roof.

This is for a roofing membrane that is not fully adhered to substrate and the pebbles are essentially acting as a paperweight. The gravel also acts as a protective measure to prevent natural debris such as leaves. Why not fully adhere. Epdm and neoprene roof seams are fastened by adhesive and pvc roof seams are heat or solvent welded.

Flat roofs in my experience are seldom totally flat. That s all there is to it. Various types of rock are embedded into asphalt roofs to add strength to the roof and help it last longer. If the roof is what is called a ballast roof it is not fastened or adhered down throughout the whole roof.

Most of the ones i have been up on had a tiny bit of slope to them to feed water to the edges for removal. If there is a complete covering of the roof with small rocks gravel then it is the top layer of a built up flat roof this protects the other layers from damage by hail or storms also people. Rocks are placed on commercial flat roofs for many different reasons.