Residential Roof Framing Spans

The provisions for prescriptive roof construction are found in chapter 8 of the irc and in section 2308 of the ibc.

Residential roof framing spans.

The rafter spans in this guide are based on the horizontal. Rafter spans are tabulated for the most common roof loads. Pitching beams 23 common installation details 25 notches cuts and. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

Span calculator for wood joists and rafters also available for the android os. Also available for the android os. 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. Ceiling joists 15 hanging beams member16 underpurlins 17 strutting beams 18 roof beams 20 verandah beams 22 garage roof.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. Continuing on from part 3. The loads are based on adjusted roof snow loads from the governing building code. Span guide for.

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. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. This is the horizontal distance from the inside surface of the supporting wall to the inside surface of the ridge board. Fully supported by.

So consider a simple gable roof on a 24 foot wide ranch framed with 2 6 exterior walls and a 1 1 2 ridge. Prescriptive roof construction the international residential code irc and the international. Contents general 2 terminologybe used for specification where alternate 3. This is known as prescriptive framing.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Here we have a wood framed gable roof. Rather the span is based on the rafter s horizontal projection. Let s consider a basic gable wood roof framing design.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.