Why Do You Put Rocks On A Flat Roof

The purpose of stone or gravel ballast on a flat roof it is not unusual to find a gravel top coat on commercial roofing systems.

Why do you put rocks on a flat roof.

There are different types and weights of gravel used on flat roofs for these purposes. On many flat roof low slope commercial buildings it s common to see gravel on top of the roof. This is still the case for the primary or base roof. The first is to protect the underlying layer of roofing materials on built up roofs burs and the second is to secure or weigh down the roofing material as is the case with single ply flat roofs.

Tar has a low melting point. Talk to ten roofing contractors and you ll get ten answers on what the gravel is for but this seems to be the consensus. Though primarily confined to built up asphalt roofing systems it can be applied to single ply epdm rubber based membranes as well. The rolls are applied to a completely cleaned stripped roof deck that has been coated in adhesive.

To protect the underlying layer of roofing materials as is the case with built up roofs burs. Have you ever wondered why contractors install gravel on flat roofs. For many years the only way you could cover a flat roof was with rolled rubber roofing. If the roof is what is called a ballast roof it is not fastened or adhered down throughout the whole roof.

In a typical tar and gravel roof which by the way is gradually being supplanted by gravelless roof systems you put down a layer of tar paper then tar and finally gravel. Rocks are placed on commercial flat roofs for many different reasons. Flat roofing is not actually flat. Gravel is used on flat roofs for two reasons.

Contractors and builders use gravel on flat roofing for two primary reasons. The rolls are cut to fit then unrolled across the roof and smoothed out to avoid air bubbles.