Long-Lasting Fire Protection
for Exposed Timber
SENTRIN FRX
Sentrin FRX is a pressure-impregnated, leach-resistant fire retardant treatment, specially formulated for external timber applications. Tested to BS EN 13501 and meeting Euroclass B or C, it delivers lasting protection against flame spread, heat, and smoke - without compromising timber strength, appearance, or durability. Suitable for cladding, decking, structural timber and more, it ensures compliance with national building regulations, even in fully weather-exposed environments.
WHY IT MATTERS
Timber is a natural and sustainable building material, but in the event of a fire, untreated surfaces can ignite quickly, accelerating flame spread and reducing evacuation time. Sentrin FRX dramatically slows this process by chemically reacting with flammable gases to form a protective char layer that insulates and suppresses combustion.
Unlike site-applied treatments or coatings, Sentrin FRX is applied in a controlled factory process, delivering reliable, long-term protection that doesn’t wash out or require reapplication. Whether you're designing for safety, compliance, or peace of mind - this treatment ensures timber performs when it matters most.
WHERE IT IS USED
Sentrin FRX is ideal for a wide range of external, above-ground applications:
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Timber cladding and rainscreens
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External structural beams and columns
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Timber decking and balustrades
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Playground and landscaping structures
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High-risk areas like stairwells and escape routes
Thanks to its leach-resistant formulation and deep penetration, Sentrin FRX requires no maintenance and retains fire performance for the expected life of timber cladding, typically 20+ years, even when fully exposed to the elements.
THE PROCESS
Treatment Process
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Vacuum Phase – Removes air from the timber structure
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Flood & Pressure Impregnation – Fire retardant is forced deep into the wood
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Final Vacuum – Removes excess solution, which is recycled
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Kiln Drying & Curing – High-temperature drying ensures stability and activates the fire-retardant properties
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Quality Control – Each treatment is monitored by computer for consistency and performance
This process typically takes 90–240 minutes, with curing extending up to two weeks depending on species and thickness. No waste is generated during treatment.
BENEFITS
Benefits at a Glance
Certified Fire Performance
Sentrin FRX is tested to BS EN 13501 and achieves Euroclass B or C ratings, meeting stringent UK Building Regulation standards. This significantly reduces flame spread, smoke, and heat release - enhancing safety in cladding, decks, and high-risk areas like escape routes.
Maintenance-Free, Long-Term Protection
Once treated, Sentrin FRX timber offers fire protection for over 20 years without the need for reapplication or maintenance - even when fully exposed to weather. This makes it ideal for cost-effective, low-intervention building design.
No Impact on Timber Strength or Stability
The treatment does not compromise structural properties like strength, durability, or dimensional stability. This allows the timber to retain its full engineering performance while achieving high fire safety ratings.
Fully Factory-Controlled Process
Treated under ISO 9001 and WPA Benchmark FR-certified conditions, Sentrin FRX is far more reliable than site-applied coatings. You get full traceability, quality assurance, and a treatment certificate for every batch - giving you confidence in compliance and performance.
Installation & Handling
HANDLING AND INSTALLATION
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Fixings: Use stainless steel or hot-dip galvanised hardware for outdoor applications.
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Storage: Store timber ventilated and unwrapped to avoid moisture build-up.
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Reworking: Rip-sawing, planing, and thicknessing are not permitted after treatment. Cross-cutting is acceptable, but avoid exposing untreated faces.
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Health & Safety: Use standard PPE when handling; avoid use near drinking water or food contact surfaces.
Need Support?
Whether you’re navigating regulations or planning your next build, our technical team is here to help with: fire classification support, project-specific advice or CE marking & Declaration of Performance (DoP) get in touch to ensure your timber meets the right standards for your project.