Gable Roof Ridge Beam Size

For 2 x 4 rafters use a 2 x 6 ridge board.

Gable roof ridge beam size.

Calculate the initial value for d then round it up to the nearest inch. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. For each application a pdf download is available. Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3.

This tells you the size of the beam needed to support the porch s roof. The ridge board s length will be the outside measurement of the building plus the length of the overhang at both ends. Loading conditions are detailed below. In the example d calculates to 7 75.

This sizing guide for roof rafters will help determine what you need for your small project. For 2 x 6 rafters use a 2 x 8 ridge board and so on. Also see assumptions for table development. Here we have a wood framed gable roof.

After they re up you can snap a line to mark and trim the tails in a nice straight line to make up for any ridge warp or marking cutting and fixing errors. Refer to sfpa s publication southern pine headers beams download in publications that includes all size selection and allowable load tables. Let s consider a basic gable wood roof framing design. Continuing on from part 3.

Choose a ridge board that is one size larger than your common rafters. There are several variables to consider when determining the proper rafter size. Gable roof framing calculator plan diagram with full dimensions for a good straight fascia add an extra inch or 2 to the tails of all your rafters total length. This means the example porch would need a 6 inch by 8 inch beam.

A ridge beam is a structural member used to support the ends of the rafters at the ridge transferring it s loads to posts or gable end walls. Some shed rafters do not incorporate ridge beams either due to small size or lack of technical know how. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.