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.
The average bundle of asphalt shingles generally covers 1/3 of a square, but since bundles are meant to be light enough to carry, more bundles of heavier shingles may by necessary to cover a square. The quality of shingles varies depending on their weight. Premium asphalt shingles last the longest, and can weigh up to 430 pounds per square, while standard shingles weigh about 230 pounds per square. Cedar shingles weigh 160 to 320 pounds per square when dry, and are wrapped in four bundles per square, weighing between 40 and 80 pounds per bundle.