Roof Rafter Sizes Uk

Span tables for purlin supporting rafters to bs 5268 7 6 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.

Roof rafter sizes uk.

There could be many rafters supporting a roof. This calculator helps you make the rafters of the suitable sizes required for your roofing. Half building width minus 1 2 ridge thickness. 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.

Usually 400 450 or 600mm but any value can be used up to 610mm max. 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. To establish the rafter length we calculate the following. Here the number is 1166 66 inches.

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. See rafter run to outer wall calculator below. Rafter is a sloping beam usually wood that supports a pitched roof. 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. Clear span on plan. 4 8 2 2 4 for one half of your roof s width b skip this step if you already know what measurement half the width of your roof is. As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.

Allow for ridge thickness when determining rafter run to outer wall. 2 4 x 1 1034 refer to image to the right 2 65. Rafter slope min 15 max 45 degrees. This is the distance between rafter centres.

This demo version is fixed at 1m clear span. Here the number is 941 86 inches. The full version allows any size. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

For pitched roofs flat roofs and ceiling joists.