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. All the figures are based on roofing tiles or slates laid on. 2 by 3 i e 50mm by 75mm. Purlins are the wood of 2 by 2 or 50mm by 50mm we nail the roofing sheets on.

Purlins near roof edges or changes of roof slope are subject to higher wind forces than interior purlins. Roof pitch between 15 and 22 5 degrees with rafter spacing. 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. 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.

All about purlin span for metal roof. Usually 400 450 or 600mm but any value can be used up to 610mm max. 2 by 2 i e 50mm by 50mm. It is suitable to use for roof sheeting from fiber cement.

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. 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. J l neal subject. Wood timber are sawn into various sizes amongst are.

For pitched roofs flat roofs and ceiling joists. 2 by 4 i e 50mm by 100mm. Purlins are spaced based on designs or type of roofing sheets. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16.

This is the distance between rafter centres. Building control guidance note purlin. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees. They both can be combined well to make sure that the space below the roof.

Surveyors span tables for designing roof rafters. Purlin and rafter roofs timber sizes and construction details author.