Thermafleece CosyWool Slab - Sheep's Wool Insulation

Thermafleece CosyWool Slab Sheep’s wool Insulation is a high-performance, eco-conscious insulation solution made from a rich blend of British sheep’s wool and recycled fibres. Ideal for use in walls, roofs, and floors, this flexible but firm slab is designed to friction-fit snugly into cavities, delivering outstanding thermal and acoustic insulation.

Engineered with 75% pure wool and 25% recycled polyester fibres, CosyWool Slab Insulation offers exceptional breathability, helping to regulate moisture and improve indoor air quality. The clever wool blend enhances both durability and insulating efficiency, outperforming many products with a higher wool percentage and Research has shown that this product outperforms alternative products currently on the market that feature a higher percentage of wool

Why Choose CosyWool Slab for Your Insulation Project?

Installing Thermafleece CosyWool Slab sheep’s wool insulation will significantly help reduce heat loss though the building envelope, improving energy efficiency and lowering both energy bills and the property’s carbon footprint. This natural insulation solution supports a more sustainable and eco-friendly building performance.

Cost-Effective Performance
Designed with affordability in mind, Thermalfleece CosyWool Slab insulation offers premium wool insulation at a competitive price point. The energy savings achieved mean it quickly pays for itself.

Sustainable and Low Impact
Thermalfleece CosyWool Slab insulation reduces carbon emissions by many tonnes over the life of use while locking in CO₂.

Naturally Breathable
The breathable nature of natural fibres helps maintain healthy humidity levels, protecting both your building and its occupants.

Safe to Install
Free from harmful chemicals, Thermaflece  CosyWool is safe to handle without specialist gear, which is ideal for DIY and professional installers. It’s also recyclable and can be easily and safely be disposed of at the end of its life.

Reliable, Long-Lasting Insulation
The addition of a high-lofting binder ensures the slabs retain their shape and structure over time, maintaining performance for decades, creating a long-lasting Insulation option.

Certified Quality
Manufactured under ISO 9001 standards and rigorously tested for thermal, acoustic, and fire performance, CosyWool Slab meets key UK building requirements.

Specifications

Performance

• Thermal Conductivity: 0.038 W/m·K - provides excellent energy efficiency and heat retention.
• Water Absorption at 100% Relative Humidity: Up to 30% of weight - helping to regulate internal moisture levels.
• Specific Heat Capacity: 1800 J/kg·K - contributes to thermal mass and improved comfort.
• Mould Resistance: Passes CUAP 2002-01-25 - tested for resistance to fungal growth.
• Moth & Beetle Resistance: Complies with ISO 3998 - protected against insect attack.
• Water Vapour Resistivity: 9 MN·s·g⁻¹·m⁻¹ - allows the building to breathe while retaining thermal performance.
• Fire Safety (Flammability & Smoulder): Passes BS 5803-4 - meets UK fire performance criteria.
• Reaction to Fire: Tested to EN 11925-2 - achieves EuroClass E fire classification.
• Thickness Recovery: Certified to EN 823 - recovers to stated thickness after compression.
• Dimensional Stability: Conforms to EN 1604 - maintains shape and fit over time.
• Sound Insulation: Achieves airborne sound reduction of Rw = 40 dB when installed correctly.

Standards

• Manufactured to Quality Standard: ISO 9001 — ensures consistent production and performance.

Environmental

• Global Warming Potential (GWP, A1–A3): Just 0.06 kgCO₂e — extremely low embodied carbon.
• Recycled Content: Contains 20% recycled fibres — reducing environmental impact.
• Recyclability: 100% recyclable — can be safely disposed of or reused at the end of life.
• Environmental Product Declaration (EPD):
• Registration Number: S-P-04468
• Valid Until: 31/10/2026

Available Sizes

• Thicknesses: 50 mm, 75 mm, 100 mm, 140 mm
• Widths: 370 mm and 570 mm
• Length: 1200 mm (all sizes)

Installation Guidance

Thermafleece CosyWool Slab is easy to work with, requiring no specialised tools or protective clothing (though PPE is advised in dusty or tight spaces). Keep slabs dry and out of direct sunlight before installation. If exposed to moisture, remove and replace affected areas. Not suitable as a standalone cavity barrier.

Eco-Friendly Insulation that Works

Thermafleece CosyWool Slab offers a responsible, efficient, and healthy way to insulate your home or building. Whether you’re renovating or building new, it delivers trusted performance while protecting the planet.