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.
Roof rafter sizes uk.
To establish the rafter length we calculate the following.
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.
Clear span on plan.
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.
Half building width minus 1 2 ridge thickness.
Surveyors span tables for designing roof rafters.
2 175m is your rafter length.
Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.
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.
Rafter slope min 15 max 45 degrees.
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.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
For pitched roofs flat roofs and ceiling joists.
Print full scale rafter plumb cut templates and birdsmouth templates fold template over rafter to mark or cut through.
This is the distance between rafter centres.
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.
There could be many rafters supporting a roof.
This calculator helps you make the rafters of the suitable sizes required for your roofing.
It is one of a series of sloped structural members that extend from the ridge or hip to the wall plate designed to support the.
This demo version is fixed at 1m clear span.
Here the number is 1166 66 inches.
Allow for ridge thickness when determining rafter run to outer wall.
Rafter is a sloping beam usually wood that supports a pitched roof.
See rafter run to outer wall calculator below.
