Timber Roof Purlin Span Tables

Purlins near roof edges or changes of roof slope are subject to higher wind forces than interior purlins.

Timber roof purlin span tables. Alternatively you can use the lumberworx design tool. Roofs and not for traditional purlin and rafter roof construction. This free tool gives construction industry professionals the ability to design wall floor and roof members using the lumberworx product range. Surveyors span tables for designing roof rafters.

Purlin is a well known material in the field of architecture structural building or structural engineering. Other more complex load condition spans can be determined with our free hyne timber design 7 5 software. Pitched roof timber sizes. It is a horizontal bar that used to support building at the roof structurally.

The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. Building control guidance note purlin and rafter. 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. 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.

Span tables lumberworx has created the span tables below to assist in the specification of the lumberworx members. All the figures are based on roofing tiles or slates laid on timber laths over sarking felt. For pitched roofs flat roofs and ceiling joists. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs.

There is an available purlin for every type of roofing material including purlin span for metal roof which is the most common material type to use this item. For simple construction such as domestic construction this can be determined from span table supplements in as1684 2 and as1684 3.