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.
Garage roof timber sizes.
Surveyors span tables for designing roof rafters.
125mm x 16mm nominal size high quality scandinavian redwood tongue and groove boards.
Common joists sizes are 200 x 50mm 175 x 50mm and 150 x 50mm.
Wherever possible joists should span the shortest distance.
The joists will normally be placed at 400mm centres but no more than 600mm centres.
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.
This sizing guide for roof rafters will help determine what you need for your small project.
This is the distance between joist centres.
For pitched roofs flat roofs and ceiling joists.
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.
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.
The sizing and spacing will depend upon the loads imposed on them and the required span.
There are several variables to consider when determining the proper rafter size.