How To Cut Roof Rafters With A Speed Square

2 lay out a plumb cut on a rafter.

How to cut roof rafters with a speed square.

This is the first episode of a series that i am making called construction rocks this series will help teach skills useful when building a house. In this first installment we ll start with roof framing. The key to accurately cutting the necessary angles is the proper use of a basic carpentry tool the framing square. Before miter saws and even since professional carpenters used speed squares as a quick saw guide for cutting 45 and 90 degree angles.

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. The roof rafters provide integral structural support to the roof. And the secret to cutting correct rafter angles is the speed square also known as the rafter square which was invented in 1925 by carpenter albert j. Common rafters are the most common type of rafter in construction.

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. 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. The secret to making a good rafter is cutting the proper angle. The rafter square or speed square does more than mark perpendicular lines.

Ability to read a tape measure ruler. The rafter square makes it easier to cut the correct angles for anyone looking to make custom roof trusses. Familiarity with using a speed square. Today we are tackling a big beginner lesson which is common rafter layout and cutting.

Locate the desired roof pitch on the common top cuts table of.