Blowing Wool - Supafil 40


Masonry cavity walls


Blowing Wool


Supafil® 40 is a non-combustible Blowing Wool, manufactured with a water repellent additive, designed for installation by approved technicians in existing external masonry cavity walls.


  • British Board of Agrément approved
  • Excellent thermal  performance
  • Non-combustible A1 Euroclass Reaction to Fire
  • Manufactured using a water repellent additive to prevent water ingress.
  • Provides a full-fill solution, even if walls are built out of tolerance, reducing the risk of unwanted heat loss.
  • Dry system requiring no mixing on site, leading to a clean installation with minimal waste.
  • Installed by approved technicians, with no need for product storage on site, improving site efficiency and removing the risk of theft.



Thermal Conductivity (W/mK)Euroclass Reaction to Fire ClassificationPack DimensionsPack Weight (kg)Packs Per Pallet


Supafil 40 BBA logo - Certificate No: 88/2033
Eurofins Gold
A1 Euroclass Fire Rating
Green Guide Rating A+
CE Marking
Bureau Veritas

Declaration of Performance

Click the button below to view our Declaration of Performance


Additional Product Information


We care for the people who make our products, the people who use them and the world we all depend on.

 Whilst we are dedicated to supplying sustainable high performance insulation solutions for enhanced energy efficiency in buildings, we also continually strive for improvements in our manufacturing and supply chain operations so to improve quality and minimise our impact on the environment. All Knauf Insulation production locations have state-of-the-art manufacturing equipment and meet the highest quality standards as well as they are supported by an ongoing research and development program. All of our products including Supafil 40 are sustainably manufactured.

At Knauf Insulation, we have 7 key sustainability considerations:

  • to conserve natural resources
  • to reduce the evironmental effects of our own processes
  • Treating people fairly, along the supply chain
  • Delivering our products efficiently
  • Building a comfortable and healthy indoor environment
  • Performance reporting
  • Recognition