How To Cut Roof Rafters With A Speed Square

If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters.

How to cut roof rafters with a speed square.

Ability to read a tape measure ruler. The roof rafters provide integral structural support to the roof. The rafter square or speed square does more than mark perpendicular lines. The key to accurately cutting the necessary angles is the proper use of a basic carpentry tool the framing square.

Building plans will specify the slope a roof should have. Locate the desired roof pitch on the common top cuts table of. 2 lay out a plumb cut on a rafter. The rafter square makes it easier to cut the correct angles for anyone looking to make custom roof trusses.

A bevel square can also be set to the plumb cut angle and used to mark the rafter s top overhang and bird s mouth cuts. Common rafters are the most common type of rafter in construction. Before miter saws and even since professional carpenters used speed squares as a quick saw guide for cutting 45 and 90 degree angles. Familiarity with using a speed square.

Today we are tackling a big beginner lesson which is common rafter layout and cutting. Photo 2 shows how to use the speed square to mark a 33 1 2 degree angle the same as you would need on a rafter tail for a roof with an 8 12 pitch. In this first installment we ll start with roof framing. Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.

Demonstrate the basics on calculating laying out and cutting a common rafter for either a full gable roof or for a shed roof on a porch or small addition.