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

As an example pivot the speed square until the numeral 30 aligns with the opposite edge of the piece of material.

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

At the corner of the square there is a pivot point. Now that the square has been lined up on the 30 degree mark however the angle drawn will be a 30 degree angle. Follow the bottom edge of the rafter to where it meets the common pitch reading. Hold the pivot point against the board and move the square until your desired angle lines up with the edge of the board.

Step 3 note the number on the common scale parallel with the 45 degree angle of the square. It s often marked right on the tool. Read the pitch on the side of the rafter square. 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.

Use a spirit level to mark a straight vertical line across the rafter. With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level. The pivot is a point at one end of the lip about which you can rotate the speed square to find angles.

This is called the plumb line. Line up the pivot point on the bottom edge of the rafter. If not the 0 degree mark should be at the opposite. The hash marks with corresponding numbers between 1 and 30 refer to the roof s rise angle.

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. Place the pivot point against the shingles. Because the speed square is a 90 degree angle each line on the diagonal represents one degree for a total of 90. Draw a line down the pivot point edge of the speed square on the exact same side that the 90 degree line was drawn.