Garage Roof Rafter Size

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.

Garage roof rafter size.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. If you re building rafters and aren t sure where to start when determining the length of your lumber you re in the right place our rafter stock size calculator shows you how long your rafters should be so you ll know what you need in terms of framing lumber dimensional lumber studs and more. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.

There are certain situations where offset is more practical than opposed rafters which usually occurs on very. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. It is always better to have a large rafter rather than be concerned with a sagging roof. Just enter the dimensions of the roof rise and run to get started.

The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that. Surveyors span tables for designing roof rafters. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Offset rafter framing can be done on garage roof framing if you are building a garage from plans that are sealed by a professional architect or structural engineer licensed within the jurisdiction you are building a garage in if those designs specify rafter offset.

Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the 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. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. 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.

The closer the rafters are to each other the stronger the roof will be. 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.