Flat Roof Joist Span

Usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below.

Flat roof joist span. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. Variations in ceiling construction nonparallel ceiling joist designs require additional support construction in the ceiling. Joist breadth 47mm. Supporting imposed load for access and repair only.

At least 40mm bearing on supports. Live load is weight of furniture wind snow and more. Dead load weight of structure and fixed loads 15 lbs ft2. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres.

Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. Span is clear span between supports. Maximum slop3 10 deg. 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.

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. 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. Span calculator for wood joists and rafters also available for the android os.

Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. Permissible clear spans for flat roof joists to bs 5268 7 2 imposed load. Also available for the android os. This is the distance between joist centres.

View joist rafter tables. Floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2. 1 ft 0 3048 m. 1 psf lbf ft2 47 88 n m2.

Joist spacing of 24 inches is allowed for spans between 16 to 20 feet using 2 inch by 10 inch lumber of these three grades.