Rafter Sizes And Spans

Calculations to bs 5268 2.

Rafter sizes and spans. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. Pitched roof timber sizes. The maximum spans in the table above are for the horizontal distance the rafter can span not the diagonal distance or actual length of the rafter. 2 for design parameters refer to figure 726.

2002 bs 5268 75. So if your house is 26 feet wide and the roof ridge beam is centered on the house you will need a rafter that can span 13 feet. Other more complex load condition spans can be determined with our free hyne timber design 75 software. For pitched roofs flat roofs and ceiling joists.

Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. The beam span length is fixed for this demo version. Wind classification n1 n2. Surveyors and structural engineers utilise data from tables below to help calculate the correct size.

Building control guidance note subject purlin and rafter roofs timber sizes and construction details 18 issued 010413 rev page 1 of 2. The full version allows you to design beams of any size. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction.

Rafter and joist span faq. Lets use this example and find a size of rafter that will work. Surveyors span tables for designing roof rafters. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.

All the figures are based on roofing tiles or slates laid on timber laths over sarking felt. Rafter span tables for surveyors roof construction. Pergola rafter spans for 600 mm and 900 mm spacing. If the manual load is one of the types in the drop down box please selecet this type or leave the setting at standard material if the load is not brittle.

Rafter spans for southern yellow pine douglas fir and eastern spruce. Spanman increase member sizes in accordance with australian codes if the member supports brittle loads. The lengths and sizes of joists vary depending on the species and quality of the lumber used. For simple construction such as domestic construction this can be determined from span table supplements in as16842 and as16843.