Why Put Gravel On A Flat Roof

When shingles are installed even when done properly water can become trapped under the shingle.

Why put gravel on a flat 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. Gravel on a flat roof is important for two reasons. To weigh down or secure the roofing material as is the case with single ply flat roofs. The gravel helps hold the waterproof layer down and protects it from heat and sun.

Contractors and builders use gravel on flat roofing for two primary reasons. Both factors can extend the life of your flat roof. Specifically there are two main reasons to use a ballasted roof system. The tar is then covered with gravel to keep it weatherproof.

In the summer it gets pretty soft and if left to its own devices would flow to the lowest point on the roof. The heat of the day can cause the tar or whatever you used to bubble or an edge can get picked up by the wind. Also a tar and gravel roof is very rugged and safe to walk on. Most flat roofs traditionally have tar applied over the roof decking to make it watertight.

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. Gravel is used on flat roofs for two reasons. It provides excellent protection against uv rays and is an attractive option for windows and decks that overlook the roof. Gravel is an excellent fire retardant.

Tar has a low melting point. Favourite answer the gravel is mostly put on flat felt roofs to serve as a heat barrier from the sun otherwise the felt would soften and blister and then when it was cold the creases in it would. Adding shingles can actually lessen this time. Of all the flat roofing options a tar and gravel roof is the most economical.

The weight provided by the gravel is used to anchor down the roof materials therefore using far fewer fasteners to hold the materials to the decking. However on a flat roof there is no place for the water to go.