Roof Framing Rafter Layout

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

Roof framing rafter layout.

Laying out hip valley and jack rafters takes experience and skill but if you re building a simple gable or shed roof all you need is the common rafter the basic building block of roof framing. Marking the birdsmouth and the ridge board setback. Roof framing rafter layout from one end of the rafter material using a speed square or framing square mark an x in 12 angle on the rafter and cut it. Divide the adjusted width.

The layout the next step is to layout and cut the rafter. The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope. Before you start cutting you first need to determine how long your roof rafters. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.

First i attach a set of stair gauges to my framing square so i can make precise repetitive marks. In this case i attach the gauges for a 6 12 pitch 6 in. Draw a line down the edge of the tongue as shown in illustration b of the roof layout. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.

For every foot. This is our ultimate roof rafter guide for people designing and building an off grid cabin or tiny home. Measure up a distance equal to 25 of the width of the rafter as shown in illustration c and put a mark. Calculating rafter length 1.

Measure down y height from the long point of the rafter cut and make a mark. Here we have a wood framed gable roof. This will the first point of the rafter measurement line. Learn the 1 rafter design that will guarantee your roof that is safe and strong for years to come.

Continuing on from part 3. Flip the square over and place the tongue along the line made in illustration b. Measure the width of your building. On the body of the square.

Add the length of the overhang beyond this mark and. Mark and cut the first rafter ends the first step in building the roof rafters is to cut one rafter board to length with the ends angled properly and then to mark and cut the birds mouth and seat on the rafter. Measure form the top of this line down the board to determine the line length or length of the rafter less the ridge. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.

Subtract the width of your ridge beam. Position the square at the end of the rafter board with the tongue on your left and facing away from you. Discover the pros and cons to multiple roof designs. To lay out a common rafter you need the pitch of the roof expressed in units of rise per foot of run in the gable roof example shown here a rafter with 6 in 12 pitch rises 6 in.