Framing Square Roof Rafters

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.

Framing square roof rafters.

Also known as a steel square the johnson framing square is a handy tool for carpentry. 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. In this first installment we ll start with roof framing. Input the pitch of the roof that you calculated above we ll use 7 12 for reference throughout on the framing square.

As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. Video of the day volume 0. That is on this roof there will be a 6 inch rise in 12 inches of horizontal run. The key to accurately cutting the necessary angles is the proper use of a basic carpentry tool the framing square.

It can also be used as a straight edge finding and establishing right angles and marking cut off work on widestock. Using the rafter length table below this signifies that we are looking at rafter lengths for the various types of rafters on a 6 12 slope roof. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Above my pencil is pointing to the 6 inch mark read along the front of the framing square blade the long arm.

To cut roof rafters start by fixing the stair gauges on your framing square to the dimensions of your pitch. The procedure for marking and cutting a typical 2 by 6 rafter can be adapted to rafters of any size or length by revising the materials described to your specific application. The standard two foot framing square also referred to as a carpenter s square and historically as a steel square is an l shaped tool that is used to mark angles for cuts used in building framing particularly roof rafters stair stringers and many other cuts or angles other than 90. To measure out your cuts you ll need a pencil a framing square and movable stair gauges to make accurate cuts.

Ability to read a tape measure ruler. Familiarity with using a speed square. This is a video lesson of the common rafter layout for ed105. The angle of the cuts made on the pitch end of the rafters will depend upon the rise you ve calculated.