The square of shingles covers the 100 square foot area. This is 10 foot by 10 foot area. One square of shingles generally comes in three bundles for standard duty or four bundles for heavy duty shingles. 80 square would be the big roof, and would represent 8000 square feet. You wish to replace shingles on the home. House is a 24 feet by 32 feet ranch style home with 12:12 pitch roof. Roof has one foot overhangs all around. Lowest cost you can determine for shingles is $40 per square. Compute cost of replacing shingles on house.