Gable Roof Ridge Beam Size

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

Gable roof ridge beam size.

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. For each application a pdf download is available. 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. 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.

Calculate the initial value for d then round it up to the nearest inch. This means the example porch would need a 6 inch by 8 inch beam. Continuing on from part 3. Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3.

Loading conditions are detailed below. Also see assumptions for table development. The typical gable roof diagram above shows the r length measured from the outside wall to the middle of the ridge beam the rafter section diagram below typical of a shed or patio cover roof shows the r length measured from the outside wall to the outside face of the ridge beam either one is acceptable depending on which type of roof you are building but if you are using the. This tells you the size of the beam needed to support the porch s roof.

Choose a ridge board that is one size larger than your common rafters. A ridge beam runs the length of the shed roof connecting every pair of rafters. In the example d calculates to 7 75. For 2 x 4 rafters use a 2 x 6 ridge board.

Let s consider a basic gable wood roof framing design. Refer to sfpa s publication southern pine headers beams download in publications that includes all size selection and allowable load tables. This sizing guide for roof rafters will help determine what you need for your small project. Here we have a wood framed gable roof.

However our instructions include making shed rafters with a ridge beam. Some shed rafters do not incorporate ridge beams either due to small size or lack of technical know how. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.