Roof Timber Sizes And Spans

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.

Roof timber sizes and spans.

Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. Click on a span to generate a full calculation you can adjust the exact span.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. For pitched roofs flat roofs and ceiling joists. All figures are based on normal loading conditions found in domestic construction. 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 following tables give details of the allowable spans and spacing for some of the more common timber sizes used in flat roof construction. All the figures are based on roofing tiles or slates laid on timber laths over sarking felt. Pitched roof timber sizes. This span table is to the format and methodology given in bs 5268 7 2.

In any other situation you should refer to trada document span tables for solid timber members in floors.