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Thermafleece UltraWool

Thermafleece UltraWool

Regular price £141.21
Regular price Sale price £141.21
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Thermafleece UltraWool is a high density, highly efficient insulation, rich in British sheeps wool and is the ideal choice if you are looking for maximum thermal performance when space is at a premium. What’s more, with a density of 31 kg/m3 Thermafleece UltraWool helps provide exceptional acoustic insulation performance.

Thermafleece is made from 75% British Wool and 25% recycled polyester fibres - a combination that outperforms alternative products with a higher percentage of wool. The rich wool blend ensures you get the full benefit of sheep’s wool with enhanced performance, breathability, durability and sustainability. Perfect sustainable insulation for roofs, lofts, walls and floors.


  • Roofs – Loft & warm roof
  • Walls – Timber frame & solid (internal)
  • Floors – All levels above DPC
  • Acoustic – Walls, floors & roofs

Why Insulate with Thermafleece UltraWool?

Insulating a property will significantly reduce the amount of energy lost from the building envelope, reducing energy consumption and carbon dioxide released to the atmosphere.

High Performance: With a Thermal Conductivity of 0.035 W/mK, Thermafleece UltraWool is the best performing natural fibre-based insulation on the market.

Cost Effective: Energy savings from using Thermafleece UltraWool mean it can pay for itself in a few years.

Long Lasting: Thermafleece UltraWool Slab contains a lofting agent to maintain durability, fibre stability and structural integrity creating a long-lasting insulation.

Quality Assured: Thermafleece UltraWool is manufactured and supplied in accordance with ISO 9001 qms.

Sustainable: Thermafleece UltraWool Slab can reduce CO2 emissions by many tonnes over the lifetime of use. What’s more, wool fixes carbon dioxide helping reduce greenhouse gas levels.

Safe: Thermafleece UltraWool is safe to handle and can be recycled or safely disposed of at the end of its life.


Thermafleece UltraWool is harmless and can be installed without gloves or protective clothing, although we recommend you wear a dust mask in enclosed spaces such as lofts. Thermafleece UltraWool is not irritating to the skin, eyes or respiratory tract.

To retain the benefits of water vapour, absorption and release, Thermafleece UltraWool roll may be used in conjunction with a vapour permeable underlay. Protect the insulation from prolonged exposure to sunlight when unpacked and avoid wetting for extended periods, store under cover and clear of the ground.

Thermafleece can be safely and easliy torn apart, but if you need a more accurate edge then we recommend the 'Roll and Cut' method using a sharp scalloped edge knife or an insulation saw:

  1. For an accurate length. Roll the insulation as tightly as possible along the width. Measure where you need to cut then taking the insulation saw / knife easily cut through. This provides a nice, neat edge and is an alternative to tearing by hand.
  2. To cut the width of the roll: Keep the insulation rolled and do not unwind. Measure the required width that you need then using the knife or insulation saw begin to cut through the whole roll. 

You can also cut Thermafleece by tightly compressing or clamping the insulation between two pieces of solid 15mm board. Overhang the fleece where you want to cut keeping the two board edges aligned. Saw cut the edge using a sharp, scalloped edged knife and keep the blade firm and square against both board edges throughout. Trim any fine remaining fibres with large scissors or shears.

Key Facts and Specification

  • Thermal Conductivity – 0.035 W/mK
  • Sound Absorption – NRC 1.05 @ 100mm
  • Sound Reduction – Rw 41-54dB @ 70mm
  • Highly Breathable
  • Made in the UK
  • Contains British Wool
  • Recycled Polyester Content: 25%
  • Can be recycled
  • Water Absorption (@100% RH): 30% w/w
  • Specific Heat Capacity: 1800 Jkg-1K-1
  • Mould Resistance: CUAP 2002-01-25: Pass
  • Moth/Beetle Proofing: ISO 3998: Pass
  • Vapour Resistivity: 9 MN·s·g-1m-1
  • BS 5803-4, Flammability & Smoulder Resistance: Pass
  • EN11925-2, Reaction to Fire: Pass
  • Fire Classification: EuroClass E
  • Recoverability and thickness, EN 823: Pass
  • Dimensional stability to EN 1604: Pass
  • GWP (A1-A3) inc. biogenic carbon: 0.11 kgCO2e for R1

R Values

 Thickness (mm) Thermal Resistance (Km2W)
50 1.43
70 2.00
100 2.86
140 4.00
190 5.43
240 6.86
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