Cavity Wall Insulation Removal & Replacement

The most common signs are damp patches on internal walls, mould growth, cold walls despite having insulation, uneven heating, rising energy bills, and peeling wallpaper or paint. If these appeared after insulation was installed, the insulation is likely the cause. Our free assessment with a borescope inspection will confirm whether removal is needed.

Yes — when insulation is installed in an unsuitable property, or installed incorrectly, it can absorb moisture from the outer wall and transfer it to the inner wall. This is one of the most common reasons homeowners need their insulation removed.

We remove mineral wool, polystyrene beads (bonded and unbonded), urea-formaldehyde foam, and in most cases spray foam. Different materials require different extraction techniques, which we assess during the survey.

Most extraction jobs take 1 to 2 days, depending on property size and insulation type. Foam insulation typically takes longer than wool or beads.

No. We drill small holes in mortar joints and remove a single brick at the base of each wall section. All holes are sealed with colour-matched mortar and the brick is replaced and pointed once extraction is complete.

We strongly recommend it. An empty cavity provides some moisture protection but very little thermal insulation — your home will lose significantly more heat. We’ll advise on the right replacement product during the assessment.

Costs start from approximately £1,500 for a single wall and can range up to £5,000 for a full extraction on a large detached property. The exact cost depends on property size, number of walls, and insulation type. We provide a clear written quote after the assessment.

If your insulation was installed under a government scheme, it may be covered by a CIGA or IAA guarantee. We can help you check whether your installation is covered during the assessment.

No. Removal requires specialist equipment — industrial compressors, high-powered vacuum units, borescope cameras, and specific nozzle attachments. Attempting DIY removal risks damaging your wall structure and failing to clear the cavity properly. It’s a job for trained professionals.

Yes, usually. An empty cavity reduces the wall’s thermal performance, so your Energy Performance Certificate (EPC) rating will typically drop while the cavity is unfilled. If you re-insulate with a suitable product after the wall has dried out, the rating normally recovers — and in many cases improves on the original score, because the new material performs better than the failed one did. If the property is being marketed for sale or let, we can advise on timing the removal and re-insulation against your EPC requirements.

We typically recommend a six to eight week dry-out window between extraction and re-insulation. The exact time depends on how saturated the failed material was, the time of year, and the wall’s exposure to wind and rain. Re-insulating before the cavity has properly dried risks trapping moisture in the new product. We reassess the wall before any new material goes in.

It can. Buyers’ surveyors often flag visible damp or cavity-bridging symptoms, and lenders may impose a retention (holding back part of the mortgage until remedial work is completed) or in some cases decline the loan. Sellers usually find it more straightforward to extract the failed insulation before listing, particularly in exposure zones where lender caution is higher. If your original insulation was installed under a government scheme, a CIGA or IAA claim may cover the cost of remediation. We can help you check.