Cavity wall clearance and material extraction

Download our Thermextract brochure

Cavity wall clearance is the process whereby debris, blockages or old insulating material is removed from a cavity. Such obstructions are found in a number of properties and can often causes issues within the home, such as creating cold spots and damp problems.

Most houses built in the UK since 1930 are constructed with cavity walls: walls formed from two thicknesses of masonry with a gap between them, held together by air ties. The construction method is intended to ensure that all moisture that may enter the cavity simply drains to the footings and safely away from the property, without ever crossing to the inner wall.

For this to work effectively, the cavity must remain completely free of debris and blockages, as such obstructions can lead to a bridge being created in the air space between the two thicknesses of masonry, resulting in moisture being transferred to inner walls rather than draining as intended. Such moisture penetration can cause a range of problems in the home, such as damp and mould issues.

This is why Domestic & General Insulation developed the Thermextract cavity wall clearance system. This solution can remove blockages in a cavity wall, ensuring the cavity operates as it should in addition to preparing it for the installation of cavity wall insulation. At this point it is important to note that cavity wall insulation does not fill the cavity in a way that bridges the air space. In fact, our Thermabead insulation material fills the cavity in such a way that any moisture that enters trickles down the beads and drains away as intended.

Additionally, the Thermextract system can remove older cavity wall insulation material, making it ideal for use if you want to improve the home’s insulation or the existing material has become damaged in some way.

How do obstructions form?

Obstructions in a cavity wall can form for many reasons, including:

Features and benefits

The Thermextract system has a number of benefits:

What do I do next?

If you have damp issues, would like to upgrade your existing insulation or have any other reason to believe your cavity may require clearing, please book a free survey with us using the button below and selecting ‘Cavity wall insulation’ from the ‘Choose an enquiry type’ drop down. We will then call you and arrange a survey where one of our friendly surveyors will be able to provide you with more information about the process and benefits of clearing your cavity wall of debris.


Book a Survey