Roof Timber Sizes And Spans South Africa

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.

Roof timber sizes and spans south africa.

All our timber rafters are available in the following lengths. 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. Please be aware many internet designs and pictures have specifications for timber sizes. 10m construction timber must be graded for strength and stiffness.

It is often compared to slope but is not exactly the same. 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. 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. 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.

Shingle roofs typically have a life span of 15 30 years while membrane roofs usually last 5 15 years. 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. Howe type truss maximum span between supporting walls. 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.

50mm x 1 200mm x 10m featu. Our experienced design teams incorporate the latest in advanced software ensuring every inch is carefully crafted and tailored to our client s expectations. Glass wool thermal insulation. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.