Flat Roof Joist Thickness

Cold roofs and warm roofs.

Flat roof joist thickness.

Also available for the android os. When installed however the shingles overlap doubling the thickness. As the single ply roofing association spra points out this type of flat roofing is strong durable completely sealed and usually lasts at least 25 30 years. A minimum thickness of 18mm these will be able to span up to 600mm.

The joists will normally be placed at 400mm centres but no more than 600mm centres. Laid with the edges of the board corresponding with joists or noggins. Wherever possible joists should span the shortest distance. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

Maximum clear span of flat roof joists in metres for sc3 timber spacing between joists size. This is the distance between joist centres. There are several variables to consider when determining the proper rafter size. Double nailed at each joist.

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. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. This sizing guide for roof rafters will help determine what you need for your small project. There are two types of flat roof.

Common joists sizes are 200 x 50mm 175 x 50mm and 150 x 50mm. Buildingregs4plans flat roof guidance provides information on flat roof deck design and materials including timberboarding plywood oriented strandboard. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.

Standard asphalt shingles add very little thickness to the roof because a standard three tab shingle is about 3 16 inch thick.