Rafter Sizes For A Pitched Roof

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.

Rafter sizes for a pitched roof.

Rafter stock size calculator. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. 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. 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.

Typical tiled roof with plasterboard on underside of rafters. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. All we do now is use a calculator to multiply 1 610 by the measurement in the book. Input the rafter span on the flat eave overhang and pitch of the 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. Click the button to calculate the stock size needed for this job. 45 get exact slope using our roof pitch calculator. For pitched roofs flat roofs and ceiling joists.

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. 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. The length of rafter per meter of run is 1 1543. Automatically calculate suitable rafter sizes enter a specific rafter size 1 3 timber strength class c16 cost effective for most applications.

This calculator is to be used as an estimating tool only. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. Pitch rise run in approx slope degrees 1 12. Surveyors span tables for designing roof rafters.

1 1543 x 1 610 1 858m. Input the rafter span on the flat eave overhang and pitch of the roof. This calculator is to be used as an estimating tool only. Rafter stock size calculator.