Why Is There Gravel On Roofs

Here s why gravel is an important component of tar and gravel roofs.

Why is there gravel on roofs.

To protect the underlying layer of roofing materials as is the case with built up roofs burs. To weigh down or secure the roofing material as is the case with single ply flat roofs. On the other hand gravel roofs are hot energy inefficient heavy moisture trapping and unstable. Of all the flat roofing options a tar and gravel roof is the most economical.

Contractors and builders use gravel on flat roofing for two primary reasons. Tar and gravel roofs are made up of multiple layers of materials. Damage from foot traffic. There are different types and weights of gravel used on flat roofs for these purposes.

The gravel layered on top manages to anchor all the material down which enables the roofers to use less fasteners. The surface is coated with bitumen and a layer of gravel or crushed rock to hold the roofing material down and minimize damage from the sun and from abrasion. Gravel is an excellent fire retardant. In the summer it gets pretty soft and if left to its own devices would flow to the lowest point on the roof.

Tar has a low melting point. The weight of the gravel is an essential key factor in increasing its importance. 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. 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.

If the gravel stones break down they become less effective and leave your important roof layers prone to wear and damage. This results in minimizing costs as well as time with no loss of quality bringing advantage to both the customer and construction companies. Unprotected asphalt has very poor resistance to weathering. This roof type is typically composed of overlapping layers of tar paper or rubber sheeting separated by tar.

The layer of gravel on a low slope flat roof is used to help keep the underlay fabric secured and to provide some protection from the elements and human interference. Gravel is used on flat roofs for two reasons. The light colored gravel also reflects the sun s heat. Gravel is added on top of tar and sometimes single ply epdm roof systems as protection from uv rays foot traffic and wear from weather.