How to Measure for Roof Plans

Replacing or repairing your roof is costly enough without the added expense of measurement mistakes. Fortunately, correct roof measurements are easy to take, even if you’ve never done it before. Save yourself time and money by following a few simple pointers to make sure you get the measurement right the first time.

100-foot tape measure
Pencil
Paper
Ladder
100+ feet of rope
Calculator

Instructions

- 1
  Draw a diagram of your roof. Your sketch doesn’t need to be perfect, but it should include architectural details like ridges, valleys, dormers and chimneys.
- 2
  Break the diagram into basic geometric shapes (squares, rectangles and triangles). Start with the largest areas of your roof and work down. Number each section on your diagram.
- 3
  Use a tape measure to find the length and width of each section of your roof. For triangles, measure the base and height. Mark each of these measurements on your diagram.
  
  If you prefer to take measurements from the ground, simply measure the length of your house (including roof overhang) for sides that run parallel to the ground. To measure sloped sides, throw one side of a rope over the peak of the roof and mark both ends at the eaves. Measure the distance from one mark to the other and divide by two.
- 4
  Find the square footage of each section of your roof by multiplying length by width. For triangles, multiply base by height and divide by two.
- 5
  Add the totals from each section together.
- 6
  Divide your total by 100 to find the total squares of roofing materials you need. (“Squares” is a unit of measure used to indicate 100 square feet.)

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