Gravel Ballasted Roof Weight

Ballast tar gravel roofing.

Gravel ballasted roof weight.

When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary. For built up roofing the gravel was generally 25 5 inches in diameter. Drawbacks of a ballasted roof system. Ballast stone traps a lot of dirt making patching difficult.

Roofs with pavers as ballast can be used as outdoor patios. The weight of roofing constructions above the truss rafter may be estimated with the calculator below. The gravel can be applied in far less time than using a specially designed screw and plate fastening pattern. The stones used in ballasted roofing are generally 1 5 2 5 inches in diameter and applied in a thicker layer.

A loose ballasted roof where you have 1 to 2 inches of gravel is more on the order of 12 psf. 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. Adds a lot of weight to the roof system typically 10 15 pounds per square feet. Check out eng tips forum s policies here.

Gravel on a ballast roof system. Extremely difficult to find a leak in this system since the membrane is well hidden. Ballast is a different style of gravel which is applied to single ply roofing systems. On the other hand ballast roofing might be the right choice for your commercial property if you live somewhere with a ready source of ballast rocks gravel of the appropriate size and you prefer the aesthetic look and texture of the larger stones.

I ve had the same questions i think that the 6 psf range given in many tables is for a multi ply roofing with gravel that is impregnated into the top layer. The gravel used in built up roofing what the roofing contractors were used to was not the same as that used in a ballasted roof. Although the primary purpose of ballast is to weigh down the roofing materials it also offers similar protective benefits as described above. The single ply membrane and other roof components including thermal insulation are loose laid.

The buildup is ballasted with a gravel layer of at least 50 mm and 80 kg m 2. None asphalt roll roofing. Felt tar and gravel roofing 3 ply 4 8 lb m ft 2 23 4 kg m 2 felt tar and gravel roofing 4 ply 5 3 lb m ft 2 25 9 kg m 2.