Do the standard sizes apply to planed timber?

No, standard sizes generally apply to rough sawn timber unless otherwise specified.

What is the permissible tolerance for timber length?

Typically +50 mm and -0 mm, ensuring timber is never supplied shorter than the requested nominal length.

What increments are standard lengths supplied in?

Standard lengths are generally supplied in multiples of 100 mm (0.1 meters).

IS 1331

: 1971

cut sizes of timber

CurrentSpecializedSpecificationBIMMaterials Science · Timber and Timber Stores

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This standard specifies the preferred cut sizes of timber for use in structural framing, doors, windows, and general construction purposes. It establishes standardized dimensions and permissible tolerances to rationalize the timber trade, ensure interoperability, and minimize wastage during milling and construction.

cut sizes of timber

Quick Reference Values

Standard length increments100 mm

Tolerance on length+50 mm, -0 mm

Tolerance on width/thickness up to 100 mm+3 mm, -1 mm

Tolerance on width/thickness above 100 mm+6 mm, -3 mm

Measurement moisture content base12 percent (typical reference)

Practical Notes

Dimensions specified generally apply to rough sawn timber; if planed or finished timber is required, appropriate machining allowances must be added during procurement.

Always account for moisture content, as timber dimensions will fluctuate with moisture variations. Specifications are usually tied to equilibrium moisture content.