Cavity Wall Extractions and Clearance is the procedure to clear debris, obstructions and old insulating material from a cavity. These obstructions are found in a surprising number of dwellings and regularly cause issues within the home, such as cold spots and damp problems.

Most houses built in the UK since 1930 are constructed with cavity walls. These walls are designed from two widths of masonry with a break between them, held together by wall ties. This building method is intended to ensure that any external influences that pass into the cavity can simply drain away to the footings, away from the property, therefore there is no ingress to the inner wall.

For this to work effectually, the cavity must remain completely clear of debris and obstructions, as such impediments can lead to a conduit being formed in the air space between the two widths of masonry, resulting in moisture being conveyed to inner walls rather than draining as intended. Such moisture permeation can cause a range of problems in the home, such as damp and mould issues.

This is why Surveying Cymru’s partners utilise the BBA Registered cavity wall clearance system. This solution can remove blockages in a cavity wall, ensuring the cavity functions as it should in addition to preparing it for the installation of cavity wall insulation.

It is important to note that cavity wall insulation does not fill the cavity in a way that bridges the air space. In fact, the Bonded Bead insulation material fills the cavity in such a way that any moisture that enters trickles down the beads and drains away as intended.

Furthermore, the extraction 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.



Speech Mark Surveying Cymru
Speech Mark Surveying Cymru


Obstructions in a cavity wall can be created in any number of ways including:

  • The cavity was not cleared properly during construction
  • Building work, such as replacing windows or fitting a conservatory, resulted in rubble left behind in the cavity
  • During general home improvements, such as fitting a vent of a balanced boiler flue

Features and benefits

The extraction system has a number of benefits:

  • Extractions can be carried out for both full and partial cavity clearance
  • Suitable for use on most cavity constructed properties
  • Resolves existing damp transference issues through clearance of existing debris
  • No maintenance is required
  • If you believe you have problems that may be linked to any of the above then please contact us and we will arrange for one of our surveyors to call out and do an inspection to identify the problem.