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Every proprietary timber product in Calcs.com carries the characteristic values its manufacturer publishes. Knowing where those numbers come from tells you what to verify before you rely on a result.

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What a characteristic value is

A characteristic value is a strength or stiffness property used as the starting point for design. It is not a design capacity on its own. Under AS 1720.1 in Australia, characteristic values cover bending, shear, compression and tension. They are combined with capacity and modification factors to give a design capacity. NZS 3603 and the New Zealand timber modules follow the same idea with their own factors. Under EN 1995, declared characteristic values come from the product standard and the manufacturer’s declaration of performance. Examples are EN 14374 for LVL and EN 12369-1 for OSB panels.

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Where the numbers in Calcs.com come from

Calcs.com takes characteristic values directly from the manufacturer’s published specification guide or design guide. Values are not derived, averaged or interpolated from test data by Calcs.com. Each brand page at calcs.com/manufacturers names the source document and its date for every product family. If a product publishes bending strength that varies with depth, the section database holds the value for each depth rather than one rounded figure.

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Why docs does not list the values

Suppliers revise datasheets on their own schedule. A table of numbers copied into docs would go stale without anyone noticing. You would then have two versions of the same property to reconcile. The current set of values lives in two places. One is the brand page at calcs.com/manufacturers. The other is the section itself, once you select it in a calculator. Both are updated together when a guide changes.

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Checking the values used in your calculation

Select the product and size, then review the section properties shown in the calculator and in the calculation report. Compare them against your supplier’s current guide before you issue the design.

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If a value looks out of date

Email support@calcs.com with the product name, the guide you are working from, including its edition date, and the property in question. Including a link to the supplier document speeds up the update. Characteristic values are an input to your design, not a substitute for checking it. Confirm product availability and properties with the supplier for the project at hand.