14+ Weight Of Asphalt Shingles Per Square Foot Pics . When there is a flush mounted electric array, it can add an extra 3 pounds of weight per square foot. • a square of shingles is a roofing term for 100 square feet of material. Asbestos Cement Hot Rolled Roofing Shingles, Surface ... from 4.imimg.com Asphalt shingles are the most affordable roofing material, averaging $120 per 100 square feet. If you plan on installing asphalt shingles on your roof, it's important to keep track of how much weight they add to it, especially if your framing and this amounts to an average of 320 nails per square, or 100 square feet. Asphalt shingles are typically packaged with this in mind, but if a package of shingles covered an entire coverage per bundle (square feet). Shingles are judged by weight per square. (prices on asphalt shingles increase sporadically. Fiberglass shingles also have a high