Timber Roof Joist Span Tables Uk

Pitched roof timber sizes.

Timber roof joist span tables uk.

Should refer to trada document span tables for solid timber members in floors ceilings and roofs excluding trussed rafter roofs for dwellings or ask your lbc surveyor for advice. The floor joist span tables are based on the loadings given in the amended version of bs 6399 1 which is an imposed load of either a uniformly distributed load of 1 5 kn m or a concentrated load of 1 4 kn. This is the distance between joist centres. For pitched roofs flat roofs and ceiling joists.

Where the tables do not apply or where there are concentrated loads floor joists should be designed by an engineer in accordance with technical requirement r5. Span tables span tables can be used to determine the size of a timber member of a particular strength class required for a given span. Other span tables are based on. 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. Floor joist span tables for surveyors floor construction. Surveyors span tables for designing roof rafters. They also tell you what the maximum spacing should be between each section or timber member size of joists mm clear span c16 joist m clear span c24 joist m 47 x 95 47 x 120 47 x 145 47 x 170 47 x 195 47 x 220 1 77 2 40.

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. This table uses commonly available uk regularised timber depths. The weight of the timber floor itself consists of the timber joists the plasterboard ceiling underneath it except for suspended timber ground floors the floorboards and the nails or screws used to fix both of the aforementioned coverings. Timber and concrete upper floors.

Usually 400 450 or 600mm but any value can be used up to 610mm max usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size. Flat roof joists rafters purlin. Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support. These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

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