Roof Timber Sizes And Spans South Africa

Howe type truss maximum span between supporting walls.

Roof timber sizes and spans south africa. 10m construction timber must be graded for strength and stiffness. All completed roofs are supplied with 38 x 38 battens or 50 x 76 purlins all bracing timbers and either 38 x 76 or 38 x 114 wall plates. 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 47 x 220 5 04 4 85 4 41 75 x 170 4 50 4 38 3 99. Protection from the elements.

It is often compared to slope but is not exactly the same. Be of the howe type with the number of bays bolts at connections timber sizes and sabs grades roof pitches as specified by sans 10400 see also nhbrc manuals 2 2 and 3 4 5. In the drawings specifications for rafters state that if the poles are 100 mm to 125 mm in diameter then the truss clear spans may not be greater than 4 m. Ll3 4 a where the roof covering is of the class given in column 1 of table4 the size of rafter top chord tie beam bottom chord and the grade of timber to be used shall be selected from such table in such a way that the desired truss span does not exceed the relevant figure for maximum truss span given in column 5 as the case may be.

Please be aware many internet designs and pictures have specifications for timber sizes. All our timber rafters are available in the following lengths. 50mm x 1 200mm x 10m featu. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

Shingle roofs typically have a life span of 15 30 years while membrane roofs usually last 5 15 years. Glass wool thermal insulation. 3m 3 6m 4 2m 4 8m 5 4m 6m and 6 6m laminated beams availble on order 76mm x 228mm or made to order. If the poles are 125 mm to 150 mm in diameter then the spans may be more than 4 m but not greater than 6 m.