Weather Exposure and Fire-Retardant-Treated Timber

Reaction-to-fire performance is one part of assessing fire-retardant-treated timber. SPFR100’s published B-s1,d0 classification under EN 13501-1 applies to the certified spruce configuration. The classification describes limited contribution to fire, low smoke production (s1) and no flaming droplets or particles (d0) under the relevant test conditions.

Weather exposure and durability

For exterior applications, rainfall, humidity, UV exposure and construction detailing may affect treated timber over time. The extent depends on the product chemistry, timber substrate, exposure conditions and maintenance. A reaction-to-fire classification establishes performance for the tested configuration but does not by itself demonstrate durability after weather exposure. Durability claims and suitability for exterior use should be supported by product-specific evidence and the documented inspection and maintenance conditions.

Coatings and complete-system compatibility

Some fire-retardant systems use binders or protective coatings to reduce moisture uptake. However, adding a binder, coating or finish can change the tested product build-up and its reaction-to-fire performance. Compatibility must not be assumed: the complete substrate, fire-retardant treatment and finishing system should be supported by relevant test or classification documentation.

SPFR100 exterior-use scope

SPFR100 is available in a formulation designed for exterior timber exposed to changing weather conditions. Exterior performance depends on the substrate, application quality, construction detailing, exposure, inspection and maintenance. Follow the current Technical Data Sheet and maintenance guide for each project. The published B-s1,d0 classification under EN 13501-1 applies to the certified spruce configuration and is not an EN 16755 EXT durability classification.

Published 2 May 2024 · Updated 1 September 2026

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