Pitched Roof Rafter Span Table

For pitched roofs flat roofs and ceiling joists.

Pitched roof rafter span table.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. The figures are based on quality materials. If you look at the rafter span chart you ll notice that 2x4s can be used for rafters on spans up to 11.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. Here we have a wood framed gable roof. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. All the figures are based on roofing tiles or slates laid on timber laths over sarking felt.

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. Surveyors span tables for designing roof rafters. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. 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.

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. 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. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof. Anything beyond that you are looking at using 2x6s for most sheds.

Span calculator for wood joists and rafters also available for the android os. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Also available for the android os. Pitched roof timber sizes.

Continuing on from part 3. Let s consider a basic gable wood roof framing design. 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. The pitch and span of your roof will dictate how long of a rafter you ll need use maximum span calculator to help you find your rafter size.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.