Purpose Of Gravel On Gravel Roof

What is the purpose of the gravel on a flat tar roof.

Purpose of gravel on gravel roof.

Gravel on a ballast roof system. Generally the weight for a gravel coated roof must be within 10 25 pounds per square foot. Finding a leak in a sea of gravel can be very difficult even more difficult if the gravel has been set in a layer of hot asphalt. This sand increases traction on snow and ice when applied to slippery surfaces.

The fact that the gravel collects dirt and moisture can make patching the leaks just as difficult once they have been located. A tar and gravel roof is very heavy. Gravel provides shade to the top layer of asphalt tar protecting it from the ultraviolet rays in sunlight. A flat or low slope roof is often not a suitable surface for shingles or other roofing materials because moisture can t flow off them.

This type of edge metal is designed for installation on flat rubber roofs with gravel. One solution to this is a built up or tar and gravel roof where many layers of hot asphalt or bitumen tar paper and a waterproof membrane are applied and then covered with gravel. All purpose sand can be mixed with portland cement and gravel to make a concrete mix. It features an angled bend at the top known as the gravel stop.

Gravel roof disadvantages on the other hand gravel roofs are hot energy inefficient heavy moisture trapping and unstable. Although the primary purpose of ballast is to weigh down the roofing materials it also offers similar protective benefits as described above. Disadvantages of a tar and gravel roof. They are typically more difficult to service as the owner can t see problems developing and must clear the surface entirely to repair.

Even though the asphalt waterproofs the roof highly important for flat roofs where water and moisture can build up instead of draining off like it does on a sloped roof the gravel layer extends the life of the roof. Flat or almost flat roofs can collect a tremendous amount of water especially if their outlets or downspouts become plugged with leaves and debris. Joists or the supports for your roof may have to be strengthened before application. Ballast is a different style of gravel which is applied to single ply roofing systems.

Unprotected asphalt has very poor resistance to weathering. A tar and gravel roof will generally last around 20 years although if they are well maintained and properly installed this kind of roofing has been known to last almost 40 years. All purpose sand is a washed quikrete 50 lb. Ballast is commonly used with roofs made of tar and gravel roof alternatives.

Parts and composition of tar and gravel built up and flat roofing systems with a helpful tar and gravel roof construction diagram. Friday july 6 2018. All purpose sand is a washed coarse sand that can be used as underlayment for brick pavers and flagstones.