Flat Garage Roof Timber Sizes

Sizes of joists needed for flat roof construction.

Flat garage roof timber sizes.

This sizing guide for roof rafters will help determine what you need for your small project. Here we delve into the cost of the materials for a typical single garage flat roof. I was planning on using 4x2 c16 but i m not 100 sure if that will suffice. Maximum clear span of flat roof joists in metres for sc3 timber spacing between joists 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.

Materials required to replace a typical single garage flat roof. A cavity closer should be provided to the top of the walls to prevent fire spread and to stop damp air entering the roof space. Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support. The span is 3000mm and they will be at 400mm centres.

Where a new flat roof abuts an existing external wall the joists can be hung on metal joist hangers which are fixed to a horizontal timber plate wall bolted to the wall. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. As you may imagine there is a fair amount of weight involved here in terms of boards felt etc. Old asbestos roofs are often replaced with flat roofs.

So any timber joists that are used need to be strong enough to support this weight. Im building my garage and have just been thinking about the flat roof timbers. Just enter the dimensions of the roof rise and run to get started. These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

Flat roof with no permanent access and altitude not exceeding 100m 0 75 kn m udl 0 9 kn point load most areas exceeding 100m but not exceeding 200m excluding parts of scotland pennines north east england refer to bs 6399 3 1 kn m udl 0 9 kn point load. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Flat roofs timber sizes and construction. New osb decking boards optional 50 00 each supply and fit inc vat.

We have also provided suggested costs for waste removal labour costs profit margins and vat.