Thermafleece UltraWool – High Density Sheep's Wool Insulation
Thermafleece UltraWool – High Density Sheep's Wool

Key Facts

  • Width (mm) – 390, 590
  • Thickness (mm) – 50, 70, 90
  • Thermal Conductivity – 0.035 W/mK
  • Sound Absorption – NRC 1.10 @ 90mm
  • Highly Breathable
  • Made in the UK
  • Contains British Wool
  • Manufactured to ISO 9001 & 14001
  • Can be recycled

Thermafleece UltraWool – High Density Sheep's Wool

Rich in British sheep’s wool - designed to give extra thermal performance where depth is limited and our highest level of acoustic performance


Thermafleece UltraWool is a high density, highly efficient insulation made from 75% British sheep’s wool and  25% recycled polyester. UltraWool 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 in wall, floor and roof systems.


Research shows that using 75% wool in combination with recycled fibres outperforms alternative products with a higher percentage of wool. Our wool rich blend ensures you get the full benefit of sheep’s wool with enhanced performance, breathability, durability and sustainability.

Installing Thermafleece

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 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.

Cutting Tips

Thermafleece UltraWool can be cut using a straight edge and a Stanley knife, or simply torn apart.

For more accurate cutting, tightly compress or clamp 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.

  • Thermal Conductivity: 0.035 Wm-1K-1
  • Density: 31 kgm-3
  • Water Absorption (@100% RH): 24% 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
  • Ignition Point: >500oC
  • Spread of Fire to BS 5803-4: Pass
  • Recycled Content: 20%
  • Recyclable: Yes

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