Framing A Low Pitch Roof

Measure the outline of.

Framing a low pitch roof.

For our 4 x8 lean to example using a 2 4 rafter the depth of the birdsmouth is limited by the 1 3 depth of the rafter rule. Pitch is the amount of angle or slope the roof has. Erect one truss in. For lower pitches a built up or continuous roll roofing must be applied to keep the roof waterproof.

There are several variables to consider when determining the proper rafter size. Mark truss locations on the front and back wall caps of the structure. Metal panel roof systems for low pitch application this system uses a structural metal panel for low pitched metal roofs due to their ability to form a formidable barrier for water. To transition the eaves the horizontal fascia extends to the last rafter tail and a vertical return finishes the transition.

For a low slope residential roof there are two main options. Self adhesive flashing membrane under the shingles prevents leakage on low slope roofs. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. Then apply standard asphalt shingles over the membrane.

The membrane will outlast the shingles and seal around all nail penetrations. On the body of the square the longer side input the 12 and input the 7 on the tongue the shorter side of the square by lining up the stair gauges at the corresponding point on the square. Use a framing square to help lay out the notch based on the slope of the roof. Get on a ladder with a tape measure.

How to frame a single slope roof step 1. Input the pitch of the roof that you calculated above we ll use 7 12 for reference throughout on the framing square. Sunday august 5 2018 the traditional metal roof types such as 5v crimp shown above and corrugated are rated by the manufacturers for use down to a 3 12 pitch three inches of vertical rise for every foot of horizontal run. This is denoted two ways a 1 3 or 1 4 pitch in fractions and a 6 12 pitch in inches which means the roof rises 6 inches for each 12 inches of run.

A 2 4 wall with a 2 6 rafter can be notched for a 4 seat. This sizing guide for roof rafters will help determine what you need for your small project. Can metal roofing be used on a low slope pitch roof. At the low end of the valley the subfascias of the two roofs are mitered with a block filling in the roof framing.

Use prefabricated mono trusses for the easiest and best framing on a single slope roof. Sheathing blocking is added along the valley and the sheathing pieced in for both roof planes. This system can also be used for the steep roofs.