Garage Roof Timber Sizes

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 timber sizes.

Wherever possible joists should span the shortest distance. This is the distance between joist centres. 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.

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. They also tell you what the maximum spacing should be between each section or timber member size of joists mm clear span c16 joist m clear span c24 joist m 47 x 95 47 x 120 47 x 145 47 x 170 47 x 195 47 x 220 1 77 2 40 2 89 3 38 3 87 4 36 2 05 2 67 3 22 3 77 4 31 4 85 assumptions at 400mm centers. The joists will normally be placed at 400mm centres but no more than 600mm centres. Common joists sizes are 200 x 50mm 175 x 50mm and 150 x 50mm.

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

Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. There are several variables to consider when determining the proper rafter size.