Roof Rafter Spacing Uk

Mm this is the distance between rafter centres.

Roof rafter spacing uk.

Plasterboard on the underside of the rafter. This span table is to the format and methodology given in bs 5268 7 2. Here the number is 941 86 inches. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres.

These spans were calculated using our flat roof joist calculation. 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. 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. For pitched roofs flat roofs and ceiling joists.

Click on a span to generate a full calculation you can adjust the exact span. It is always better to have a large rafter rather than be concerned with a sagging roof. Usually 400 450 or 600mm but any value can be used up to 610mm max are there any brittle finishes e g. But they do tend to space rafters in one of several industry standard increments typically either 12 16 or 24 inches apart.

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. Surveyors span tables for designing roof rafters. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. Builders aren t bound by standard rafter spacing measurements.