Roof Weight Rating

When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary.

Roof weight rating.

There are 3 types of load rating and the cargo rating. This is all of the natural stresses imposed upon a roof such as snow loads rain loads and wind loads. Static load rating when the vehicle is stationary. Asphalt shingle or asphalt fiberglass composite shingle 2 7 lbm ft2 13 2 kg m2 metal roofing aluminum or steel panel sheet or shingle 1 2 lbm ft2 5 9 kg m2 terne plate copper bearing steel sheet 0 7 lbm ft2 3 4 kg m2 wood shingle or shake 2 4 lbm ft2 11 7 kg m2 zinc roofing 1 6 lbm ft2 7 8 kg m2.

The load rating is the amount of weight the vehicle manufacturer says the roof can handle. When you have the roof racks to support your rooftop tent fitted they will be placed around 30 inches apart. The load increases with the use of heavier roofing material. A built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof.

Though in many cases the racks can withstand greater loads to avoid damage to your vehicle it is important to understand your vehicles limitations. A clay tiled roof may have a dead load. This is highly regional as weights of snow for example range from 10 to 300 pounds per square foot based on moisture and volume of the snow. The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot.