The length of rafter per meter of run is 1 1543.
Roof rafter sizes for 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.
1 1543 x 1 610 1 858m.
All we do now is use a calculator to multiply 1 610 by the measurement in the book.
Plasterboard on the underside of the rafter.
Here the number is 1166 66 inches.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
This is the distance between rafter centres.
Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.
Usually 400 450 or 600mm but any value can be used up to 610mm max usually 400 450 or 600mm but any value can be used up to 610mm max are there any brittle finishes e g.
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.
This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m.
Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Again make sure to consult local codes.
It is always better to have a large rafter rather than be concerned with a sagging roof.
For pitched roofs flat roofs and ceiling joists.