How to measure a roof and determine squares of materials

How to measure a roof

Start by looking around and decide how to section the roof. (See plan below). The red dotted lines divide the sections. Count how many sections you have. Write this number down. Start with the largest section.

All your measurements will be, length times height. In the sample plan below all the blue arrows labeled L are the length. The red arrows are the height. The red arrow on the on the largest section of the plan below goes all the way from the front eave line, over the ridge and down the back, to the back eave line. Measure each section.

In the sample below you will have 5 different calculations and that should match the number of sections you wrote down, when you started. Add all your measurements together to get your total square footage. Measure all your hips, valleys, ridges, eaves and rakes. Divide your square footage by 100 to get how many squares of roofing material you will need.
Roof diagram

Roof calculator how to use details

Roof Calculator Software Information

Using Roof Calculator Software

Bid information Ridge & Starter per sq.

The ability to add ridge and starter to your total squares. This has nothing to do with ordering quantities.

Example: Ridge

Customer wants high priced ridge put on a 35yr comp roof. The comp shingles may cost around $47 per sq, but ridge may cost around $30 per bundle or box. So if you want to add ridge to your total squares and you entered 2, then 1 square would be added to your total squares for every 2 bundles of ridge.

Example: Starter

40yr plus comp shingles about $72 per sq , roll starter $6 per roll. So this would be 12 rolls of starter = 1 sq. The program will calculate the correct amount of squares based on the number you put in. On many roofs it would not make much difference, but a big hip roof with 300ft ridge and 300ft starter? If you don’t want ridge/starter added to your total squares then leave either blank.