Timber Roof Purlin Sizes

Roof pitch between 15 and 22 5 degrees with rafter spacing strength.

Timber roof purlin sizes.

The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. 2 by 4 i e 50mm by 100mm. This is the distance between rafter centres. Now if you are strapping the rafters 1x4 pt is usually used set at 2 intervals or closer and you double the first one at the edge of the metal.

All the figures are based on roofing tiles or slates laid on. Building control guidance note purlin. Usually 400 450 or 600mm but any value can be used up to 610mm max. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees.

All about purlin span for metal roof. Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. But for our calculations we are using 900mm. Vc row vc column vc column text timber purlins supplier we have a large range of tanalised purlins in stock for timber contruction of farm and agricultural.

2 by 3 i e 50mm by 75mm. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16. For pitched roofs flat roofs and ceiling joists. 2 by 2 i e 50mm by 50mm.

If so you should use dimension lumber like 2x4. Surveyors span tables for designing roof rafters. Purlins are the wood of 2 by 2 or 50mm by 50mm we nail the roofing sheets on. It is suitable to use for roof sheeting from fiber cement.

You don t have a nailing surface on the end of a 1x4. Purlins are spaced based on designs or type of roofing sheets. Purlin and rafter roofs timber sizes and construction details author. As per as1684 and as4055 spanman adopts a nett pressure coefficient applied along the full length of the purlin of cpn 2 0 for non cyclonic zones n1 to n6 and cpn 2 5 for cyclonic zones c1 to c4.

Wood timber are sawn into various sizes amongst are. Roof pitch between 15 and 22 5 degrees with rafter spacing.