Roof Rafter Spacing Uk

For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.

Roof rafter spacing uk.

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. For pitched roofs flat roofs and ceiling joists. Mm this is the distance between rafter centres. Surveyors span tables for designing roof rafters.

Builders aren t bound by standard rafter spacing measurements. Rafter run outer wall this should be measured starting from the center of the roof span and then extending to the very edge of the exterior wall. It is always better to have a large rafter rather than be concerned with a sagging roof. This span table is to the format and methodology given in bs 5268 7 2.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Plasterboard on the underside of the rafter. Usually 400 450 or 600mm but any value can be used up to 610mm max are there any brittle finishes e g. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres.

But they do tend to space rafters in one of several industry standard increments typically either 12 16 or 24 inches apart. Here the number is 941 86 inches. Click on a span to generate a full calculation you can adjust the exact span. These spans were calculated using our flat roof joist calculation.