How To Find Roof Pitch Using A Speed Square

Use a level and a pencil to make a plumb vertical line on one face of an existing rafter.

How to find roof pitch using a speed square.

Directly below the 6 inch mark on the framing square read the required rafter length 13 42 per foot of run for a 6 inch rise 6 in 12 roof. Place the pivot point on the square against the bottom of the rafter and align the 90 degree angle side of the square with the pencil mark. To find the pitch just place the pivot point against the shingles. You have a perfect 45 degree angle for easy corners.

How to measure roof pitch with a speed square. Let us show you how to accurately determine roof pitch using simple tools level and measuring. Finding roof pitch isn t rocket science it s simple geometry. Place the level horizontally along the rafter until it contacts the roof sheathing avoiding any protruding roof nails.

You can also use a speed square to find level if you re on the job without a spirit level. 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. Working from the interior side of the roof you ll need access to a roof rafter to measure the pitch. You can use a speed square to find pitches.

Simply brace the lipped side of the speed square against the edge of your board pencil a line up the hypotenuse of the speed square and voilà. 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. To calculate the required rafter length multiply the total run length half the building width plus the width that the roof is to overhang the house wall by this number 13 42. If you need to find the pitch of an existing roof all you need is a level and a tape measure.