How To Find The Pitch Of A Roof Using A Speed Square

As a matter of fact finding the pitch of a roof was the motivating factor for how this tool was invented in the first place hence it s official name the rafter square.

How to find the pitch of a roof using a speed square.

Roof pitch is expressed as rise over run so 12 in. The trick here is understanding the number on the framing square is the unit rise per foot of run. Set the level on the edge of the speed square as shown below then place the heel of the speed square on a rafter or gable edge of the roof. A speed square and level can be used to easily find the pitch of a roof.

You can also use a speed square to find level if you re on the job without a spirit level. Note the number on the common scale parallel with the 45 degree angle of the square. You can use the speed square to mark an angle such as when cutting a rafter tail by holding the pivot point against the board. Number on framing square 228 204 x 12in.

204 x number on framing square 228. Holding the pivot point in place swing the speed square lip away from the board. You can use a speed square to find pitches. Then place your tape at the 12 in.

A speed square will have two specialty protractor angle guides on the inside of the tool which has both common rafter angles and hip valley angles marked out. The hash marks with corresponding numbers between 1 and 30 refer to the roof s rise angle. Next hook the tape measure to the level where it meets the sheathing and extend it out to make a mark at 12 in. 13 412 is the unit rise in inches per foot of our example roof run.

To find the pitch just place the pivot point against the shingles. The rise over run numbers give you the pitch. Learn more about roofing. 228 204 x 12 13 412.

Find your desired angle along the hypotenuse for instance if you want to mark a 30 degree angle perfectly. Swing the square until you read the desired angle on the board s edge and make your mark. The pitch of the roof is read where the bottom of the rafter crosses this scale.