There are different types and weights of gravel used on flat roofs for these purposes.
Gravel flat roofs.
Roof gravel provides a protective layer to flat roofs reducing the weather damaging effects from uv rays and heavy snow hail and wind.
It provides excellent protection against uv rays and is an attractive option for windows and decks that overlook the roof.
To weigh down or secure the roofing material as is the case with single ply flat roofs.
Gravel is used on flat roofs for two reasons.
Gravel to protect built up.
Also a tar and gravel roof is very rugged and safe to walk on.
Gravel roof disadvantages on the other hand gravel roofs are hot energy inefficient heavy moisture trapping and unstable.
Gravel is an excellent fire retardant.
Built up roofs or burs also called a tar and gravel roof is a well established and popular style of flat roof that is made up of alternating layers of roofing felt or fiberglass and asphalt that is applied with heat which combine to make a long lasting sturdy roofing system.
Built up roofing bur was the most common type of flat roof before modified bitumen and membrane roofing were developed.
For many people the built up roof is what comes to mind when they think of flat roofs.
A bottom layer or two of insulation board multiple intermediate layers of tar or asphalt alternated with layers of roofing felt and a top layer of gravel.
Our roof gravel is available for delivery in tunnel lift bulk bags allowing an easy method of transporting the gravel onto a roof using a crane not provided.
To protect the underlying layer of roofing materials as is the case with built up roofs burs.
A built up flat roof bur is made up of tar and gravel.
Gravel roof advantages most gravel roofs are inexpensive to build offer some protection to vulnerable asphalt against uv damage and the stones are very durable.
Built up roof bur the traditional hot tar and gravel roof is built from three or more plies of waterproof material alternated with hot tar and ballasted by a layer of smooth river stone.
Bur consists of many layers.
However if epdm roofs are spray applied then the chance of the seams pulling away from the roof is significantly lowered.
Of all the flat roofing options a tar and gravel roof is the most economical.
Built up flat roof replacement.
Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot.