Three easy steps to help you find the surface area of a roof using SketchAndCalc™

Step 1 – Find the ‘Pitch’ of the roof.

In order to measure the area of a roof you will first need to find the roof’s pitch, which is the number of inches the roof rises in 12 inches.

Take a level, tape measure, flashlight, and a pencil into the attic.

Mark off 12 inches on the level and place it down horizontally against the roof rafter.

Now measure vertically with the tape measure from the 12-inch mark on the level straight up to the underside of the rafter.

That measurement is the number of inches the roof rises in 12 inches.

Now, in the table titled ‘Roof Area Pitch Multiplier’ found here:

identify the pitch you just measured in the left column. Look along to the right and make a note of the number in the multiplier column, you’ll need this later to measure the area of a roof in step 3.

Step 2 – Trace the roof’s perimeter in SketchAndCalc™.

Login to SketchAndCalc™, and select ‘Show Maps’ from the Menu.

Search the homes postal address from the map controls that appear in the top left corner.

When zoomed in, switch to satellite view. Using the line drawing tools, draw the perimeter of the roof.

TIP: Line length labels are displayed as you draw. If you find these label’s prevent you from measuring the area of a roof clearly, just switch them off from Menu / Settings / Application. You can also adjust the grid transparency and drawing line weight.

Regardless of complexity (multiple ridge lines, hips, valleys etc), if the roof has a single pitch or incline throughout, you can simply draw to measure the area of the roof and collect the area results from the bottom right corner.

If the roof has multiple pitches you’ll need to draw these separately. After drawing the perimeter of the roof, add a new drawing layer with the + (plus) symbol found in the bottom right corner. Then proceed to measure the area of the roof that has a different pitch.

Step 3 – Area x Multiplier

Take the area result and multiply it by the pitch multiplier you noted in step 1. The result is the surface area of the roof.

Further details can be found on our Blog at

SketchAndCalc™ – Area in an Instant
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How to Measure the Area of a Roof

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