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Several Australian and New Zealand suppliers brand their glued laminated timber with their own designations. Matching those designations to the standard GL grades helps you read a supplier quote, a span table and a Calcs.com calculation together.

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Design with the named product where you can

Calcs.com carries proprietary glulam products from Hyne Timber, NeXTimber, Tilling Timber and ITI as named sections. Selecting the product directly is the better option, because the calculation then uses the properties the manufacturer publishes for that product. Use grade matching to compare a branded product with a standard grade. It also helps when a product is not in the section library.

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Standard GL grades

AS 1720.1 sets out the GL grades used across Australia and New Zealand, from GL8 through to GL21. The number relates to the characteristic bending strength of the grade. A C suffix, such as GL13C, indicates a combined or unbalanced layup intended for a specific bending direction.

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Branded products in the section library

The closest standard grade for each product is not listed here yet. Select the named product in the calculator rather than substituting a standard grade.

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When a product does not match a standard grade

Some branded products are published with values that sit between GL grades, or with a bending strength that changes with depth. In those cases there is no exact standard grade, and substituting the nearest one can be unconservative. Select the named product in the calculator instead. The full set of sizes and published properties for each brand is listed at calcs.com/manufacturers, for example calcs.com/manufacturers/hyne.

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Webinar: specifying glulam and CLT

Ben Cox of NeXTimber covers how glulam and CLT are made in Australia, compliance pathways, and a worked GL13 example in Calcs.com.

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Confirm before you specify

Always confirm the grade, the layup and current availability with your supplier. Grade matching is a reading aid, not a substitute for the supplier’s design guide or for your own check of the finished design.