the difference between a political and a physical boundary is that a physical map shows geographical features like mountains and rivers while a political map shows boundaries.
Standard Weight. Standard asphalt shingles generally weigh about 190 pounds per 100 square feet, based on information from U.S. Inspect, a property inspection company. The weight of asphalt is especially important if you want to install a new layer of asphalt roofing over an existing layer.A roof measuring 1,600 square feet that has two layers of standard asphalt shingles on it is holding about 6,000 pounds of shingles..S. Inspect indicates that dimensional shingles can be 50 percent heavier than standard asphalt roofing. Therefore, they could weigh about 285 pounds per 100 square feet. Heavier shingles reduce the chance the underlayment will wrinkle, according to the National Roofing Contractors Association.
1 Lightweight â installed roof designs weigh less than 2 pounds per square foot. 2  Resilient â RUBEROIDÂ® TORCH SMOOTH MEMBRANE's polyester mat core allows it to resist splits and tears due to its pliability and elongation characteristics.  Durable â specially formulated modified asphalt for lasting performance.