How To Use A Framing Square For Roof Rafters

The skinny length is called the tongue.

How to use a framing square for roof rafters.

Locate the desired angle on the hypotenuse side of the square and pivot the tool until that angle s notch lines up with the top edge. Layout the plumb cut and level cut for the rafter tail. I go over a. Next set the framing square on top of the rafter beam and use a pencil to trace the outside edge of the framing square s tongue.

The thicker longer section is called the blade. More project and tips. Lay a framing square flat on the board to be used as a rafter near one end. Place the framing square on a table with the skinny length pointing right.

Place the square with its fence on the top edge of the lumber. Determine the slope or pitch of the roof by referring to your building plans. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

The length of the plumb cut is determined by the width of the fascia board. For a common rafter or for each of the other rafter types these tables give the length of the rafter per foot of horizontal run. On both the long and short arms of the framing square are marked various framing tables giving rafter lengths roof slopes and the proper angle of cuts for various roofing connections such as a rafter end abutting the ridge board the birds mouth cut at the rafter segment that rests atop a wall plate hip and valley rafter cuts and other information. You are looking at the face of the framing square.

Above we see the key to the lines in the rafter length table. To cut roof rafters start by fixing the stair gauges on your framing square to the dimensions of your pitch. The horizontal blade should align with the bottom edge of the board at 12 inches and the vertical tongue should align at the roof pitch. Place a 2 by 6 board on sawhorses to lay out the first full length or common rafter.

To use the rafter length tables on the framing square blade front you need first to understand the type of rafter you are cutting. How to build roof rafters using a framing square. It is always better to have a large rafter rather than be concerned with a sagging roof.