Rafter Sizes For A Pitched Roof

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.

Rafter sizes for a pitched roof.

Rafter stock size calculator. Rafter stock size calculator. Click the button to calculate the stock size needed for this job. 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.

Input the rafter span on the flat eave overhang and pitch of the roof. Pitch rise run in approx slope degrees 1 12. This calculator is to be used as an estimating tool only. All we do now is use a calculator to multiply 1 610 by the measurement in the book.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Rafter length using angle v r 2cos a rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. The length of rafter per meter of run is 1 1543.

Area span on the flat. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. 45 get exact slope using our roof pitch calculator. Automatically calculate suitable rafter sizes enter a specific rafter size 1 3 timber strength class c16 cost effective for most applications.

1 1543 x 1 610 1 858m. Input the rafter span on the flat eave overhang and pitch of the roof. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. For pitched roofs flat roofs and ceiling joists.

You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed. Surveyors span tables for designing roof rafters. This calculator is to be used as an estimating tool only. 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.