Structural Timber Specification

APA Guidelines Structural Timber Specification

National Structural Timber Specification

The National Structural Timber Specification (NSTS) refers to the use of structural timber wherever UK building regulations apply. A similar specification is already in place for steel and concrete. It is specific to UK construction and was produced by the Timber Development UK, formed by the merger of TRADA and the Timber Trades Federation. Access the latest version here.

It provides guidance for those using the supplementary Project Specification for Structural Timber which is available only to trade body members. Designers can download a number of templates to guide their use of timber products for a specific project, within NSTS guidelines.

NSTS works in conjunction with Eurocode 5. While this design standard covers requirements for mechanical resistance, serviceability, durability and fire resistance, it does not refer to specific national building regulations, nor does it include properties such as thermal or sound insulation, which are covered by NSTS.

All Eurocodes are under review and there are plans to add an ‘Execution’ section. This would remove the need for the NSTS.

The guide below matches US trademarked products with the relevant NSTS clause number and tells you which UK/EU standard applies.

APA Structural Products NSTS Material Clause No. EU and UK Standards
Plywood 5.2.5 (BS) EN 13986
OSB 5.2.4 (BS) EN 13986
LVL 5.2.3 (BS) EN 14374
I-joists 5.3.1 Manufacturers’ own EU or UK  Technical Assessment
Glued laminated timber 5.2.2 (BS) EN 14080
Cross-laminated timber   5.2.7 Manufacturers’ EU or UK  Technical Assessment
Structural softwood lumber 5.2.1 (BS) EN 14081-1
Structural Insulated Panels (SIPS) 5.4.2 Manufacturers’ EU or UK Technical Assessment