Roof Timber Sizes And Spans

All the figures are based on roofing tiles or slates laid on timber laths over sarking felt.

Roof timber sizes and spans.

These spans were calculated using our flat roof joist calculation. This span table is to the format and methodology given in bs 5268 7 2. All figures are based on normal loading conditions found in domestic construction. For pitched roofs flat roofs and ceiling joists.

Click on a span to generate a full calculation you can adjust the exact span. Surveyors span tables for designing roof rafters. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in flat roof construction. 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.

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. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Pitched roof timber sizes.

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