For pitched roofs flat roofs and ceiling joists.
Roof rafter sizes uk.
Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.
Rafter is a sloping beam usually wood that supports a pitched roof.
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.
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.
2 4 x 1 1034 refer to image to the right 2 65.
Allow for ridge thickness when determining rafter run to outer wall.
Here the number is 941 86 inches.
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.
The full version allows any size.
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.
Print full scale rafter plumb cut templates and birdsmouth templates fold template over rafter to mark or cut through.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
To establish the rafter length we calculate the following.
Rafter slope min 15 max 45 degrees.
Surveyors span tables for designing roof rafters.
Half building width minus 1 2 ridge thickness.
There could be many rafters supporting a roof.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
2 175m is your rafter length.
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.
This demo version is fixed at 1m clear span.
See rafter run to outer wall calculator below.
This calculator helps you make the rafters of the suitable sizes required for your roofing.
Clear span on plan.
Here the number is 1166 66 inches.
