Span Tables
Engineered span tables for our full range of structural timber
Woodhouse Timber manufactures span tables for our F7 structural grade, GL8 laminated beams, and TerraFrame range, covering the timber sizes and spans builders, carpenters, and frame and truss fabricators rely on for rafters, beams, joists, and bearers.
These tables are designed to ensure that our timber products meet the requirements of the relevant Australian Standards, which are essential for safe and reliable construction.
What is a span table, and how do you read one?
A span table shows how far a piece of timber can stretch between two supports before it needs extra support underneath. Match your timber size against your spacing, and the table gives you the maximum span for that combination.
Begin by confirming the product and structural grade being used, as F7, GL8 and TerraFrame each have separate spanning needs and tables. Next, identify the relevant application, such as a rafter, beam, joist or bearer, and locate the corresponding section of the guide. Match the required spacing with the appropriate column and the timber size with the correct row to determine the maximum allowable span.
The technical diagrams provided with each table should also be reviewed, as they explain how spans and support points are measured. Where a project falls outside the scope of the standard tables, assistance should be sought from a structural engineer, or you can search for a retailer to talk through the right product for the job.
Construction standards
Our span tables are built around AS 1684 Residential Timber Framed Construction, which sets out how timber-framed buildings go together across Australia. Our F7 and GL8 members are graded to AS 1720 Timber Structures, and construction should also meet the National Construction Code (NCC), along with any local council requirements that apply to your project.
A maximum roof pitch of 25 degrees is assumed for the Span Tables, providing guidelines for properly using and installing our timber products in roofing structures.
All handling, cutting, and installation of structural timber should follow the standards set by the relevant Workplace Health and Safety Authority.
Frequently asked questions
What is a span table used for?
It tells you the maximum distance a piece of timber can safely bridge between two supports, so you can check a rafter, beam, joist, or bearer is right for the job before you build with it.
How do I read a span table?
Match your timber size to the row and your spacing or loading to the column. Where they cross is your maximum allowable span in millimetres. Always confirm you’re looking at the table for the right product and grade first, since spans differ between them.
What's the difference between F7 and GL8?
F7 is a stress grade applied to solid sawn timber under AS 1720. GL8 is glue-laminated timber, built up from smaller sections bonded together to span further and carry more than an equivalent piece of solid timber the same size.
What's the difference between a joist and a bearer?
Bearers are the primary horizontal supports a structure sits on, typically running between posts or piers. Joists sit on top of the bearers and support the decking or flooring above. Each has its own span table, since they carry different loads.
What spacing is used for deck joists?
Spacing depends on the joist size, grade, and decking material, and it’s set out in the relevant span table rather than being a single fixed number. 450mm centres are common for residential decks, but always refer to the table for your specific joist size before assuming.
Do I need an engineer to use a span table?
Every job is different. If you are ever unsure, we recommend consulting with a professional, such as an engineer, to ensure your project is structurally sound.
What's the difference between Weatherproof and TerraFrame?
Weatherproof, treated to H3, suits above-ground outdoor applications. TerraFrame, treated to H4, is built for timber installed closer to the ground, where moisture exposure is higher.
Is finger-jointed pine as strong as a single length of timber?
Yes, when it’s manufactured to AS 5068. Finger jointing removes natural defects and mechanically joins shorter lengths, and the resulting member is graded and rated the same way as any other structural timber of that grade.
Time-proven timber products, available around the country fast, flexibly & frequently.
Manufactured across our national network and backed by FSC® certification (C120464), every span table on this page reflects timber produced to the same specification, wherever in Australia it’s supplied.
When you need fit-for-purpose timber products manufactured to go the distance, you need Woodhouse.