Cavity Wall Insulation
If your house has cavity walls, there is a gap between the inner and outer leaf doing nothing except letting heat out. We fill it with bonded polystyrene beads from the outside, and every installation comes with a 25-year insurance-backed guarantee.
Bonded bead fill with a 25-year insurance-backed guarantee. How the guarantee works
- Bonded EPS bead fill
- Installed from outside
- 25-year insurance-backed guarantee
- 9.97/10 Checkatrade
- 5.0 Google
Our company is a top-rated service provider
40 Checkatrade reviews in the last 12 months £2 million public liability 10-year workmanship guarantee, 25 years insurance-backed on damp proofing and cavity wall insulation
Verified reviews
What customers say
“We were in the middle of selling our house when the buyer's mortgage was declined due to spray foam insulation in the loft. From the first call the team were knowledgeable, honest and reassuring. The spray foam was removed professionally, the loft was left tidy, and most importantly we received full certification.”
Verified customer 10/10Spray foam removal · BL3
“The team arrived and got straight on with the work, removing the old insulation and then straight on with installing the new. They were polite and answered questions we had, and when they had finished they cleaned up and asked us to have a look to see everything was alright. Very impressed.”
Carol O 10/10Loft insulation · PO12
“Great — quickly installed, friendly and super tidy.”
Ryan F 10/10Loft insulation · WF3
“We contacted EcoTrust after spray foam insulation in the loft caused problems with our house sale following the mortgage survey. They explained clearly why the foam was an issue and set out exactly what needed to be done. After completion we received the necessary paperwork, which was accepted by the surveyor, allowing the sale to move forward.”
Verified customer 10/10Spray foam removal · M2
“The 2-man team arrived just after 8am and immediately covered the stair and landing carpet prior to starting. They explained exactly what they were going to do, hoovered the roof space following removal of the 2 layers of old insulation, then fitted the new wool insulation and hoovered all my carpets. Friendly, polite and professional.”
Verified customer 10/10Loft insulation · CW11
“Really excellent job done. EcoTrust sorted out our damp porch area using damp course injections, salt neutralising treatment, a membrane as well as repointing and installing an air brick. It was plastered, left neat and tidy and ready for decorating. Liam's communication and advice was excellent throughout.”
Jess G 10/10Damp proofing · CW9
“From initial contact they were highly professional and very thorough with their initial assessment. Very professional and easy to have around the home. Communication was excellent and they even phoned if they were going to be a little late. Kept us informed at all stages and invited us up into the loft to check on progress.”
Verified customer 10/10Spray foam removal · BL5
“I would highly recommend EcoTrust. From start to finish they have been extremely professional. Booking in a survey was easy. Liam turned up on time, was very pleasant and informative, and gave me an instant quote which was very competitive. On the day the lads turned up on time, put down dust sheets and got on with the job in hand.”
Nigel B 10/10Loft insulation · BB10
“We had ongoing damp issues throughout the downstairs of our home. Ben and Lee were excellent from start to finish. They carried out repointing works externally to resolve the source of water ingress, then completed a full damp proof course and installed a damp proof membrane internally. Everything was explained clearly from the outset.”
Verified customer 9.33/10Damp proofing · M28
“No crappy selling technique, just the facts. Very understanding and helpful. They have done a great job at removing the spray foam and cleaning up after themselves as well. They hoovered everything — I think the loft is cleaner now than when they started.”
Verified customer 10/10Spray foam removal · CW10
“I used EcoTrust to insulate and board my loft. The two installers who carried out the work were wonderful — really considerate, helpful in their advice, and they cleaned up after themselves and worked really hard throughout. I would have no hesitation in recommending the firm to anyone.”
Verified customer 10/10Insulation & boarding · S36
“After recently having loft insulation replaced, EcoTrust came back to fix a hole in the ceiling and replaster. Ben and Lee were beyond any expectations we could have asked for. Being conscious of mess due to dogs in our home, they went above and beyond — there literally wasn't any. Would certainly use again.”
Simon R 10/10Ceiling repair · SY10
“Very professional. Team worked well clearing and cleaning the loft space prior to installing new insulation. They were polite and respectful and kept me fully informed throughout.”
Deborah T 10/10Loft insulation · WR3
“Polite and conscientious team. They worked hard and answered any questions we had. They took photos of the loft after they'd cleared it of boarding. After they'd put the insulation down they encouraged us to have a look. They vacuumed the carpet afterwards although they had put a polythene covering down to protect it.”
Valerie K 10/10Loft insulation · LS24
“Very happy with the work completed removing some stubborn spray foam insulation from our loft. Hard working guys, very polite and friendly. Always kept us updated on progress and timescales. A great job and would highly recommend.”
Verified customer 10/10Spray foam removal · DN14
“From when we had the survey to when the job was finished I can't fault anything. Everyone was friendly, professional and respectful to us and our property.”
Valerie W 10/10Loft insulation · WS2
“My loft space was partially boarded and the works had left it full of dislodged old insulation and debris. I got a call immediately after requesting a quote and a visit the same week. Two men arrived and got straight to work, hardly stopping for a drink. I'm amazed they managed to keep my house so clean when they were filthy.”
Verified customer 10/10Loft clearance · WN7
“Really impressed with the whole service. We had damp showing through the living-room wall and EcoTrust came out the next day. The explanation was clear and honest, and the team carried out the treatment quickly with no mess left behind. The wall has dried out perfectly and there's been no sign of damp returning.”
Verified customer 10/10Damp proofing · BH6
What it involves
Most homes built from the 1930s onwards have cavity walls: two leaves of brick or block with a gap of around 50 to 100mm between them. Left empty, that gap is one of the main routes heat takes out of the house.
We fill it with bonded polystyrene beads. They are blown in through small holes drilled in the mortar joints and coated with a binder on the way in, so they lock together into one continuous layer. They do not settle, and they do not pour back out if someone drills the wall later.
Why we use beads
Beads do not soak up water, so they will not carry damp across the cavity the way badly installed fibre can. They flow around wall ties and into corners, which leaves fewer cold spots, and because they are bonded they stay where they are put.
Not every wall is ready for it. Walls facing driving rain, cavities full of builders’ rubble, and walls with failed pointing or render need sorting first. That is why the survey comes before the price, and why we will tell you if your wall is not suitable.
How the job runs
Start to finish
- We survey the wallsWe check the cavity with a borescope, measure it, and look at the pointing, render, gutters, air bricks and damp course. If a wall is not suitable, you hear it from us at the survey.
- You get a fixed price in writingWhich walls are being filled, what it costs, and the guarantee terms, all on the quote before you agree to anything.
- We drill and fillSmall holes are drilled in the mortar joints in a set pattern, and beads and binder are injected until each section is full. Air bricks and vents are kept clear. The work is done from outside.
- Holes made good, guarantee issuedEvery hole is filled with mortar matched as closely as we can to yours. You get your 25-year insurance-backed guarantee and the paperwork for the house file.
The guarantee
25 years, insurance-backed
Cavity wall insulation comes with a 25-year insurance-backed guarantee. Insurance-backed means the cover is held by an insurer, not just by us, so it stays in place for the full 25 years even if something happened to the company.
What you get
- 25 years of cover from the date of installation
- Backed by insurance, not only by our word
- Terms written into your quotation before you agree
- Guarantee paperwork issued when the job is finished
Worth knowing
- The 25-year insurance-backed guarantee applies to cavity wall insulation and damp proofing only
- Other work, such as pointing or repairs, is covered by our 10-year workmanship guarantee, set out on your quote
The price covers
What is in, and what is not
Both halves matter. A quote that lists everything and excludes nothing is usually hiding the extras until the invoice.
Included
- Survey with a borescope inspection of the cavity
- Bonded polystyrene bead fill to every suitable wall
- Air bricks and vents kept clear, sleeved where needed
- Drill holes filled with mortar matched to your brickwork
- Site left clean, waste taken away
- 25-year insurance-backed guarantee
Not included
- Repairs found at survey, such as pointing, render or gutters, which we price separately so you can decide
- Taking out old insulation that is already in the cavity. See cavity wall insulation removal
Evidence-led work
Recent jobs, start to finish
Spray Foam Removal · SheffieldSpray Foam Removal in Sheffield: 50m² Loft Restored50m² · Five working days
Loft Insulation · ManchesterLoft Insulation in Manchester: 100m² Reinsulated to 300mm100m² · Two days
Loft Boarding · PrestonLoft Boarding in Preston: 74m² of Storage Without Crushing the Insulation74m² · Three days
Damp Proofing · ManchesterDamp Proofing in Manchester: Entrance Hall Taken Back and Replastered
Spray Foam Removal · BournemouthSpray Foam Removal in Bournemouth: Roof Reopened and Reinsulated
Loft Insulation · LeedsLoft Insulation in Leeds: Old Insulation Out, 300mm In, 15m² Boarded
Loft Boarding · NottinghamLoft Insulation and Boarding in Nottingham: Raised Deck Over New Wool
Spray Foam Removal · BurnleySpray Foam Removal in Burnley, Lancashire56m² · Two days
Loft Boarding · County DurhamLoft Boarding and Insulation in County Durham270mm wool · One day
Loft Insulation · Leeds300mm Loft Insulation in Leeds, West Yorkshire35m² · One day
FAQs
The things everyone asks
How do I know if I have cavity walls?
Look at the brickwork. If every brick shows its long side, it is usually a cavity wall. If you can see rows with the short ends of bricks showing, it is usually solid. Most houses built since the 1930s have cavities. We confirm it at the survey with a borescope.
Is there any mess inside the house?
No. The work is done from outside, through the mortar joints. We need access to the outside walls, and that is about it.
Will cavity wall insulation cause damp?
In a suitable wall, installed properly, bonded beads do not carry water across the cavity. Most damp problems blamed on cavity insulation come from walls that should never have been filled, or from defects that were already there. That is why we check the outside first and will not fill a wall that is not ready.
What does the 25-year guarantee cover?
It is an insurance-backed guarantee on the installation, so the cover stays in place for the full 25 years even if something happened to us. The exact terms are written into your quotation before you agree to anything.
How long does it take?
Most houses are done in a day. We will give you the timing for your house at the survey.
My walls already have insulation in them. Can you top it up?
If the existing fill is patchy, wet or failing, the right answer is usually to take it out and start again. That is a different job, covered on our cavity wall insulation removal page.
Free survey, and a price in writing
No obligation, no doorstep sales. If we are not the right people for the job, we will tell you that instead.