Strong Flat Roof Rafters

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.

Strong flat roof rafters.

Rafters are installed piece by piece during the construction of the roof. 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. Live load is weight of furniture wind snow and more. 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.

In finished space insulation is placed between the rafter boards and drywall or other material is fastened to the face. 1 psf lbf ft2 47 88 n m2. I joists make for a strong flat roof but you have to pay attention to the connections at the ridge and eaves when wood i joists are used as rafters connections at the structural ridge and the tops of exterior walls must be detailed properly. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. They join at the peak of the roof by connecting to the opposing rafter or to a ridge beam that runs the length of the peak of the house or shed. The roof rafters provide integral structural support to the roof.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 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. Rafters are beams that run from the peak of the roof to the top plate of the supporting walls.

You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed. 2 are indicated below. They are nailed securely to exterior wall plates and to each other. Rafter boards are fastened to the ridge board at the peak and the top plate where they join the wall.

Dead load weight of structure and fixed loads 15 lbs ft2.