How To Find The Angle Of A Roof With A Speed Square

At the corner of the square there is a pivot point.

How to find the angle of a roof with a speed square.

Follow the bottom edge of the rafter to where it meets the common pitch reading. Place the pivot point against the shingles. Now that the square has been lined up on the 30 degree mark however the angle drawn will be a 30 degree angle. Align the lip of the rafter angle square along the plumb line.

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. Line up the pivot point on the bottom edge of the rafter. Step 3 note the number on the common scale parallel with the 45 degree angle of the square. With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1.

Draw a line down the pivot point edge of the speed square on the exact same side that the 90 degree line was drawn. It s often marked right on the tool. Step 2 find an angle. Read the pitch on the side of the rafter square.

The hash marks with corresponding numbers between 1 and 30 refer to the roof s rise angle. Hold the pivot point against the board and move the square until your desired angle lines up with the edge of the board. If not the 0 degree mark should be at the opposite. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level.

This is called the plumb line. Holding the level and speed square level locate the measurement on the speed square where it meets the bottom edge of the rafter to find the angle of the roof in degrees. 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. Use a spirit level to mark a straight vertical line across the rafter.