What Fire Rating Do I Need for Timber Cladding?

Fire safety is no longer a secondary concern in UK construction—it's a legal, performance, and insurance priority. One of the most frequently asked questions we receive at QTD Ltd is:

“What fire rating do I need for timber cladding?”

Whether you're specifying materials for a residential extension or planning cladding for a multi-storey commercial development, understanding the fire classification of timber cladding is critical for compliance, durability, and occupant safety.

What Is a Fire Rating?

A fire rating refers to how well a material or construction element can resist fire, usually expressed in minutes (e.g., 30, 60, 90, or 120). In the UK and across Europe, materials are tested under BS EN 13501-1, which assigns a Euroclass rating from:

• A1/A2: Non-combustible

• B: Very limited combustibility

• C–F: Increasing levels of flammability

For timber cladding, the primary target is Euroclass B-s3,d0—a rating that reflects very limited flame spread, smoke production, and flaming droplets.

UK Building Regulations for Timber Cladding

Under Approved Document B of the UK Building Regulations, fire performance requirements for external wall materials vary by building type and height:

Building Type / Height	Fire Rating Requirement
Domestic buildings under 11m	Not always required, but recommended
Buildings over 11m (England, Wales, Scotland)	Euroclass B-s3,d0 or better
High-rise residential (18m+)	Combustible cladding (including untreated timber) is prohibited
Schools, hospitals, or public-use buildings	Typically require fire-rated timber
Urban or high-risk settings	Fire-retardant cladding is highly advised

🛑 Note: Even below 11m, fire-retardant-treated timber is often a safer and more futureproof option, especially for buildings near boundaries or in dense urban areas.

Timber Species & Their Fire Resistance

Different types of timber naturally perform differently in fire, but treatment is usually necessary to achieve compliance:

Recommended Timber Cladding Species:

• ThermoWood® Softwoods (e.g., Redwood Pine, Radiata Pine): Naturally more fire-resistant due to heat treatment, but should still be impregnated with fire retardant for Euroclass B compliance.

• ThermoWood® Hardwoods: Denser, offering better natural performance and ideal for further fire treatment.

• British Grown Larch, Douglas Fir, Western Red Cedar: Durable softwoods with moderate fire resistance; require fire-retardant treatment to meet modern standards.

At QTD, we offer guidance on the best timber species and treatments based on your project’s fire rating requirements.

Types of Fire Treatments for Timber Cladding

To meet Euroclass B ratings, timber cladding must be factory-treated using one of the following approved methods:

Fire Retardant Options:

• Pressure Impregnation: Deep treatment using water-based retardants (e.g. Burnblock), ideal for long-term protection.

• Tank Submersion: Soaks timber in a fire-resistant solution that chars and self-extinguishes under heat.

• Intumescent Coatings: Applied on the surface, they expand under high temperatures to form a protective barrier.

• Brushed-on Site Coatings: Less reliable and only suitable in controlled dry conditions with certified products.

Always ensure your timber is treated before installation, and that it meets Euroclass B-s3,d0 as required by your building type and location.

Fire Compliance Checklist for Timber Cladding

Before specifying or purchasing cladding materials, make sure you receive:

• Certification to BS EN 13501-1 (including Part 6 & Part 7)

• Details of the fire treatment method and the product used

• Traceability and documentation from a certified treatment facility

Choosing a trusted supplier like QTD Ltd ensures your timber is tested, traceable, and compliant.

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Final Thoughts: Fire Safety First

If you’re asking, “Do I need fire-rated timber cladding?” the safest approach is to assume yes, especially for buildings over 11m or in public and high-risk spaces.

Key Takeaways:

• Use Euroclass B-s3,d0-rated timber cladding for all buildings over 11m.

• Choose factory-treated timber from reputable suppliers for compliance and traceability.

• Always request certification and proof of fire performance.

Need Help with Timber Fire Ratings?

At QTD Ltd, we offer a range of fire-rated timber cladding solutions, including ThermoWood®, British-grown timbers, and certified fire-retardant treatments to suit every specification.

👉 Get in touch for tailored advice or to order fire-compliant timber samples today.