Garage Roof Timber Sizes

Surveyors span tables for designing roof rafters.

Garage roof timber sizes.

The sizing and spacing will depend upon the loads imposed on them and the required span. For pitched roofs flat roofs and ceiling joists. This sizing guide for roof rafters will help determine what you need for your small project. This is the distance between joist centres.

Common joists sizes are 200 x 50mm 175 x 50mm and 150 x 50mm. Size of roof joist 400mm 450mm 600mm 47 x 97 1 84 1 81 1 74 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50. Wherever possible joists should span the shortest distance. You don t have wallplates for flat roofs.

They re made to fit one car and can be used as a shed or even a small bedroom. You can use plain or treated but treated are obviously better for a roof which might get damp and suffer insect attack. 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. You need 170mm 400 centres otherwise 200mm joists.

125mm x 16mm nominal size high quality scandinavian redwood tongue and groove boards. Usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below. Garage roof sheets are made from a variety of materials and each material comes with its own benefits so it is important to select the best one for your garage roof. We use 100mm x 38mm framework which run top to bottom in the roof rather than the purling effect which has a higher likelihood of twisting then we support these with 100mm x 38mm trusses.

There are several variables to consider when determining the proper rafter size. The joists will normally be placed at 400mm centres but no more than 600mm centres. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. 150mm joists wont span 4m.

Metal roof sheets metal garage roof sheets are popular due to their ability to withstand extreme weather conditions affordability and ability to withstand high temperatures. That being said you have other options.