Maximum Spans For Roof Rafters

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

Maximum spans for roof rafters.

Also available for the android os. 2 are indicated below. For pitched roofs flat roofs and ceiling joists. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

1 psf lb f ft 2 47 88 n m 2. 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. Surveyors span tables for designing roof rafters. This table is simply a sample and may not be valid for your region.

Maximum and use lumber properties as follows. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm. Dead load weight of structure and fixed loads 15 lbs ft 2. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.

Live load is weight of furniture wind snow and more. Maximum rafter span of 16 feet. Span tables for rafters to bs 5268 7 5 imposed loads of 0 75 kn m snow load are applicable to most areas where the altitude does not exceed 100 metres refer to bs 6399 3 imposed loads of 1 kn m snow load are applicable to most areas where the altitude exceeds 100 metres but does not exceed 200 metres but excluding parts of scotland pennines north east england refer to bs 6399 3. Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g.

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. 1 ft 0 3048 m. Trusses must be designed for any special loading such as. Spaced sheathing or 1x boards may be reduced slightly.

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 spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter. 2x4f 2000psif 1100psie 1 8x10 2x6f 1750 psi f 950 psi f 1900 psi e 1 8x10.