Burnblock® Fire Retardant Timber Treatment

Burnblock® is a pressure-impregnation fire-retardant treatment that elevates timber to Euroclass B (B‑s1,d0), the second-highest European fire rating.

This makes it ideal for exterior and interior timber cladding façade panels, buildings and feature walls and other visible timber elements.

Burnblock® slows ignition, limits flame spread and reduces smoke while maintaining timber’s natural texture and finish.

This empowers architects to realise their design vision safely and sustainably.

How does Burnblock® work?

Fire needs oxygen to sustain itself. Burnblock® effectively prevents oxygen from reaching the treated timber.

The process involves pressure impregnation of natural, non-toxic, fully biodegradable substances into the wood with the use of a pressure vacuum tank.

This creates a surface on the timber that, once heated, chars and releases water, preventing oxygen reaching the wood. This reduces further combustion and minimises the fire’s spread.

Registered as a trademark in 2018, Burnblock® meets rigorous fire classification standards (including EN13501, which classifies building elements based on their reaction to fire).

It provides scientifically proven protection without compromising on the natural beauty or material integrity of the wood.

Unlike many chemical-based treatments, Burnblock® contains no substances listed under REACH as Substances of Very High Concern (SVHC), making it a safe choice for people and planet alike.

We deliver this treatment with WJ FireWright, the exclusive partner for Burnblock® in Great Britain.

The entire treatment process is independently audited each year by a notified body. This gives us full CE/UKCA and ISO 9001 certification, in turn giving customers confidence their timber has been treated to the highest possible standard.

Burnblock® is 100% natural, non-toxic, non-corrosive, biodegradable, pH neutral and water-based product, as well as free of VOC emissions and toxins.

A true environmentally-considered, design-forward coating solution.

Cladding and fire safety ratings

The Euroclass system grades materials from A (non-flammable) to E (highly flammable). In its natural state, timber typically falls into Euroclass D. Euroclass A is reserved for non-combustible materials like steel and concrete.

For treated timber, Euroclass B is the highest rating realistically achievable. This means it is combustible, but with 'very limited contribution to fire'.

As well as contributing to fire spread, Euroclass has some additional classifications – smoke emission (‘s’) and flaming droplets (‘d’).

• Smoke emission: s1 (low smoke), s2 (medium smoke), s3 (high smoke)
• Flaming droplets: d0 (none), d1 (some), d2 (high)

As mentioned, Burnblock® achieves Euroclass B (B‑s1,d0), the second-highest European fire rating.

Burnblock® fire retardant treatment was specified for the Thermo-Ayous cladding on this Cheltenham development. A custom shadow gap profile, machined to sit alongside our DTC14 and DTC15 secret nail boards, was treated before installation — combining fire protection with the darker tones of thermally-modified timber against Cotswold stone.

Rebuilt three years after its original building was destroyed by arson, St Mary's Catholic Voluntary Academy required fire retardant timber cladding across all external elevations. We supplied Western Red Cedar in our DTC14 profile, impregnated with Burnblock® by FireWright and rated B-s1, d0 under BS EN 13501-1 — no flashover, very limited smoke emission, no burning droplets.

Burnblock® x Remmers: fire retardant treatment and colour coating in one factory-applied system

Burnblock® x Remmers combines Burnblock® pressure-impregnation fire retardant treatment with Remmers factory-applied colour coatings in a single system for timber cladding.

Treated and coated cladding achieves Euroclass B (B-s1,d0) — very limited contribution to fire, low smoke emission, no flaming droplets — on classified species and build-ups.

The coating range covers three colours — Light Grey (Weathered), Mid Grey and Black — in two finish tiers: single-coat (Weathered), where the timber grain remains visible, and double-coat (Solid), a fuller opaque finish. Suitable for interior and exterior cladding.

Both treatment and coating are applied at the factory before delivery. Boards arrive finished and ready to install, with no site coating required.

Browse Burnblock® x Remmers timber cladding range