UltraWool Insulation – Thermafleece

5.00 out of 5 based on 1 customer rating
(1 customer review)


UltraWool is an extremely efficient, high density insulation that is rich in British sheep wool. When struggling for space, these slabs give you the very best in performance for a fraction of the thickness required. As well as exceptional thermal qualities, the high density of 31kg/m3 helps it to provide stunning acoustic insulation as well. Reach a U-Value of 0.13W/m2K in just 270mm.

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How to Calculate how much you need

Using the thermal conductivity of this product (0.035), you can work out either the thickness you require or the U-Value you will achieve. Simply divide the Thermal Conductivity by the thickness to work out the U-Value, or divide it by the U-Value you want to reach to work out the thickness required.

0.035 / Thickness = U-Value
0.035 / U-Value = Thickness

Benefits of the UltraWool

Incredible performance means that the UltraWool is, thickness for thickness, pretty much unrivalled by any other insulation on the market. It comes in slabs, and as it is made from a natural sheep wool-rich blend it is outstandingly durable with the added benefit of being sustainable. If you want to reach a specific U-Value without taking up too much space then the UltraWool is the one to go for. It comes in a variety of widths and thicknesses, which means you can cover every inch to ensure maximum efficiency.

    • 50mm x 390mm = 14.04 m2
    • 50mm x 590mm = 14.16 m2
    • 70mm x 390mm = 9.83 m2
    • 70mm x 590mm = 9.91 m2
    • 90mm x 390mm = 8.42 m2
    • 90mm x 590mm = 8.50 m2

Made in the UK from British wool, you can’t beat how well UltraWool performs.

Installing the UltraWool

UltraWool is a sheep wool rich insulation, which means it is incredibly easy to work with. Protective gloves and clothing aren’t necessary when installing your UltraWool, however we do still advise that you wear a mask – but that’s just because your loft may be dusty! Another major benefit of the UltraWool is that it is incredibly easy to cut, as all it takes is a knife or a pair of scissors. You can even just rip it apart. Simply lay out the slabs evenly across the space you need to insulate and sit back to enjoy the benefits of having a warmer home!

Performance of UltraWool

UltraWool has a thermal conductivity of 0.035Wm-1K-1 . This means that it has fantastic insulation qualities, so you only need a thickness of 220mm to get to 0.16W/m2K, or 270mm to reach 0.13W/m2K. The density of UltraWool is 31kg/m3.

UltraWool is also highly breathable, meaning that its performance doesn’t even drop when it gets damp, and in doing so is vital for water absorption and vapour permeability.

UltraWool – Product features

    • Made in the UK
    • British Wool
    • Width – 370mm or 570mm
    • Thickness – 50, 70, 90mm
    • Thermal Conductivity – 0.035Wm-1K-1
    • Acoustic absorption – NRC 1.10 @90mm
    • Breathable
    • ISO 9001 & 14001


Reviews (1)

  1. Rated 5 out of 5


    Really happy with this product, having used it on a recent loft conversion project for my client. Easy to handle and can applied without much prior skill. The reason I bought from this website is because they were easy to contact and talk through questions. Recommended.