The questions people ask before they let anyone open up their walls. If yours is not here, ask a question and you will get a plain answer by email.
My mortgage or sale is blocked because the cavity is filled. Does removal help?
It can. Lenders and surveyors flag filled cavities where the insulation has failed or the wall was never suitable. Removing it and making the wall good deals with the cause, and the completion certificate is the evidence you give the lender.
Do I actually need the insulation removed?
Only if it has failed. Sound, dry insulation in a suitable wall is working and should stay. The survey tells you which you have: the borescope shows whether the fill is wet, slumped or missing, and the moisture readings show whether the wall is suffering.
How does the insulation come out?
Single bricks are removed at intervals along the base of the wall and below windows. Compressed air is fed in through the original injection holes to loosen the fill and drive it down, and an industrial vacuum draws it out through the openings into bags. A borescope is used afterwards to confirm the cavity is clear.
How long does it take?
Published guides put a mid-terrace at two to three days, a semi at three to four and a detached house at up to a week. Foam takes longer than wool. Your quote gives the price for your house.
Is it messy?
Outside, yes, for the duration: bagged insulation, a compressor and a vacuum in the drive. Inside, no. Nothing is opened from within the house.
Does it damage the brickwork?
The bricks taken out are reused. The mortar around them is new and matched as closely as the wall allows. On an old wall the fresh joints will be visible for a while until they weather in.
Will the house be colder afterwards?
A clear cavity insulates less than a dry filled one and more than a wet filled one. Wet insulation conducts heat out of the house, so most people with failed fill notice no loss and often a gain once the wall has dried. The re-insulating or leaving clear page covers what to do next.
How much does it cost?
It is priced by the wall area cleared, adjusted for the material and access. UK guides in 2026 put extraction at roughly £20 to £45 per square metre and a typical semi anywhere from about £1,500 to £4,600 depending on which guide you read. The costs page goes through it.
Can I claim it on my guarantee instead?
If the installation carries a CIGA guarantee and the insulation is defective, CIGA’s process can put it right at no cost to you. We are not a CIGA installer and cannot make the claim for you, but our quote and photographs can support it. See CIGA guarantee claims.
Do you need scaffold?
Usually not for a two-storey house with clear access; ladders and a tower do it. Three storeys, walls above conservatories or steep ground can need scaffold, and the quote says so.
What happens to the old insulation?
It is bagged on site and taken away for disposal as building waste. Mineral wool and polystyrene bead are inert; urea formaldehyde foam is handled with the same care but is not classed as hazardous.
Do you work in my area?
Cavity wall insulation removal across mainland England, Scotland and Wales. If you are unsure whether we cover your address, ask.
How quickly will you get back to me?
We reply within one working day to arrange a free survey and quote.
