Insulation, Cavity Wall Foam

Cavity Wall Insulation

Vaiable Width Cavities


Isothane’s foam cavity wall insulation, Technitherm® has a proven track record of providing structural stabilisation and thermal insulation benefits to both domestic and commercial properties across the United Kingdom for over 25 years.

Technitherm® is a closed cell polyurethane cavity wall insulation foam which is injected into the cavity of the property. Whilst this is usually done externally it is possible for the work to take place internally when the property is undergoing internal refurbishment. It improves the thermal values of the property and, by adhering the inner and outer leaves together provides structural stability which can eradicate the need for costly wall tie replacement work where they have corroded or failed.

Cavity wall insulation foam diagramcavity wall foam insulation from above


Technitherm® has been used to provide cost effective cavity wall insulation for many different properties across the United Kingdom. It has helped many homeowners, private landlords, housing associations, councils and businesses to achieve their aims whether that be lower fuel bills, structural stability, reduced carbon emissions or the need to provide insulation in areas subject to wind driven rain or prone to flooding.

We run an approved contractor scheme to ensure that our cavity wall foam is only installed by Isothane trained contractors to ensure a professional job everytime for anyone choosing Technitherm® and we have a nationwide network of these contractors.


Technitherm® provides a cost effective solution for properties that are not suitable for standard cavity wall insulation products for various reasons. Often these properties are described as “hard to treat” and previously it was thought that using a more costly alternative such as internal or external wall insulation was the only solution to their insulation needs. 

Technitherm® is suitable for:

  • Random Stone properties where the cavities are of uneven width.
  • Cavities below 50mm.
  • Properties which are exposed to wind driven rain.
  • High Rise buildings

Cavity Wall Insulation Foam

  • Buildings suffering from corroded and failing wall-ties.
  • Properties where a chartered surveyor has reported they are not suitable for standard insulation.
  • Properties that are prone to flooding. It is the only cavity wall insulation to pass BRE flood resilience test requirements for homes in flood risk areas

Water resistant Cavity Wall Insulation

Cavity Wall Foam FAQ’s

U-Value Request Form


Case Studies

Cavity Wall Insulation and Wall Tie Replacement

The client Homeowner in Fence Burnley the problem A part stone built house suffering excessive heat loss, high heating bills,...


Non-standard cavities - stone Stone Properties Cavity Wall Insulation

The client Blackburn with Darwen Council The problem A wide variety of houses built in the early 1900’s with variable...


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