How to Measure Squares on a Shingle Roof

Whatever type of roofing you have, it is measured in "squares," so when you get an estimate for roofing, it is broken down as a cost per square. A square is a 10-by-10 foot area of roofing, or 100 square feet.

Things You'll Need

• Extension ladder
• Measuring tape
• Pad of paper
• Pencil
• Calculator

Instructions

1. Lean an extension ladder on the eave of your roof. Make sure the ladder is secure and will not slip out from under you as you climb up to the roof.

2. Using your tape measure, measure the distance from the peak of the roof to the eave of the roof. Write this distance down on a pad of paper. Drawing a basic picture of the roof line will help you add up the measurements later, as you can place the measurement number by the corresponding roof line.

3. Measure the length of the roof with your tape measure. Write this distance down. Repeat measuring any dormers, porch roofs and secondary roofs, and write all distances down on your diagram.

4. Back on the ground, go over your measurements. Multiply the main roof's length and width. Repeat this for all secondary areas of the roof. Using your calculator, take these values and add them together. This is the total square footage of your roof. Divide this number by 100. This number represents how many squares your roof is. For example, if your roof measures 40 feet by 30 feet, the total square footage is 1,200. Divided by 100, this means your roof consists of 12 squares.

Tips & Warnings

• Do not spend a lot of time measuring the difference in distance from the top of the roof to the bottom when you measure to a valley. Use the longer of the two measurements. This will ensure you have enough material for your roofing job.

• If you don't wish to climb up to your roof, you can get a very rough estimate by measuring along the ground around the perimeter.

• Use caution when walking on the roof. Also, do not walk on the roof if the roofing material is slate, tile or clay shingles, as these materials will crack if walked on directly. Measure from the eaves only if these materials exist. For areas you can't measure, count the number of tiles on the roof and measure one tile at the eaves. Add up the tiles and use this as a means of estimation.

References

• "The Illustrated Home"; Carson Dunlop & Associates; 2003

Resources

• "Real Estate Home Inspection: Mastering the Profession"; Russell W. Burgess; 2003