The steeper the pitch, the more shingles you would need. Simply multiplying your outside wall sq. Ft. Will provide you with inaccurate results unless it is a flat roof, which you would not use shingles on.

Well multiplying 72 by 15 would only work if it is a flat roof. You would need to measure from the peak to the bottom (a), and times that by two (b), since there are two sides. Then multiply that by 72. That answer is your total roof sq. Ft (c). Divide that answer by … Read more