Summary
Cavity wall insulation removal is a specialist, low-volume job with none of the grant funding that subsidises new CWI installation — which is why it costs several times more per property than blowing insulation in did in the first place. There's no ECO4 or GBIS scheme paying toward extraction, and CIGA only funds it where a live guarantee claim is upheld. Every extraction job is either privately funded by the homeowner or covered end-to-end by CIGA's own appointed contractor at CIGA's own rates — a general contractor is very rarely competing for CIGA-funded work, so most quoting happens on the open market.
The pricing structure has three moving parts that estimators routinely get wrong: the extraction itself (driven by wall area and fill type, not by how bad the damp looks), the making-good (every drilled hole needs colour-matched pointing, and older brick makes this slower and more skilled than people expect), and the decision about what happens to the cavity afterwards. Leaving it empty is the cheapest outcome and often the right one; refilling with a more exposure-appropriate product roughly doubles the total job cost because it's effectively a second full installation on top of the extraction. Quoting "extraction" when the customer actually wants "extraction plus refill" — or vice versa — is the single most common cause of disputed pricing on this job type.
This guide gives 2026 UK pricing by fill type and scope, a worked cost breakdown showing how the quoted price is built from labour, plant, materials and margin, regional variation, the red flags that push a job to the top of its price band, and what to itemise on the quote. For the technical process — the survey, the CIGA claim route, extraction method and reinstatement options — see cavity wall insulation removal guide. For why the CWI failed in the first place, see cavity wall. For pricing a fresh installation rather than a removal, see cavity wall insulation pricing guide.
Key Facts
- Extraction only (loose fibre/bead), 3-bed semi (70–90m²) — £1,800–£3,500 quoted price, including pointing and waste disposal
- Extraction of bonded EPS bead — £2,200–£4,200; adhesive-bonded bead takes longer to break up and extract than loose fibre or loose bead
- Refill with EPS bead after extraction, same wall area — £700–£2,000, broadly the same as a fresh CWI install (see cavity wall insulation pricing guide)
- Extraction + refill (full remediation), one job — £2,500–£5,500; this is not a discounted bundle, it's the sum of two distinct pieces of work
- External treatment only (PUR foam, no extraction possible) — £1,200–£2,800; silicone masonry cream or localised re-render
- Standalone borescope survey — £150–£300; commonly credited against the job if it proceeds within a set period
- Wall tie borescope inspection (add-on during extraction) — £150–£300; a genuine opportunity, not an automatic extra
- Additional access holes for hard-to-reach areas (bay windows, gable apex, behind extensions) — £300–£800 surcharge
- Larger property surcharge, 4-bed detached (120–170m²) — £2,800–£5,000 for extraction alone
- Specialist extraction contractor day rate (crew + equipment) — £380–£550/day, higher than a standard installation day rate because of the vacuum extraction unit and its running costs
- Skip/waste disposal for extracted material — £150–£300
- Pointing/making good, per drilled hole — £6–£12 in materials and time, adding up fast across 40–70 holes on a semi
- CIGA-funded claims are priced outside this guide — where a valid CIGA guarantee claim is live, CIGA's appointed contractor and their own pricing framework apply, not an open-market quote
- VAT — standard 20% on removal/remediation work; this differs from new CWI installation, which can qualify for the energy-saving materials zero rate under HMRC VAT Notice 708/6
- CDM 2015 — extraction work involving access equipment and dust is notifiable like most other construction work
Quick Reference Table
Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.
Try squote free →| Job | Labour/plant days | Materials & disposal | Typical quoted price | Notes |
|---|---|---|---|---|
| Borescope survey (standalone) | 0.25–0.5 | — | £150–£300 | Often credited if the job proceeds |
| Extraction only — loose fibre/bead, 3-bed semi | 1–2 | £250–£450 | £1,800–£3,500 | Most common extraction job |
| Extraction — bonded EPS bead, 3-bed semi | 1.5–2.5 | £300–£500 | £2,200–£4,200 | Bonded bead is slower to break up and pull through |
| Refill with EPS bead, same area | 1–2 | £250–£500 | £700–£2,000 | Priced as a fresh CWI install; see companion install guide |
| Extraction + refill, full remediation | 2–4 | £550–£950 | £2,500–£5,500 | Sum of extraction + refill, not a discount bundle |
| External treatment only (PUR foam cases) | 1–2 | £300–£600 | £1,200–£2,800 | No extraction possible; silicone masonry cream or re-render |
| Wall tie borescope check (add-on) | 0.25 | — | £150–£300 | Priced during the extraction visit |
| Additional access holes, hard-to-reach areas | 0.25–0.5 | £50–£150 | £300–£800 surcharge | Bay windows, gable ends, behind extensions |
| Extraction, 4-bed detached (120–170m²) | 2–3 | £400–£650 | £2,800–£5,000 | Larger wall area, more holes, more pointing |
Detailed Guidance
How the quoted price is actually built
The headline figures above are what the customer pays, margin included. It's worth walking through how a specialist contractor builds up to that number, because it's the model you should use when quoting a job that doesn't fit neatly into the table.
Worked example — extraction only, straightforward 3-bed semi (~80m² wall area), blown mineral fibre, standard access, no CIGA claim:
| Cost element | Amount |
|---|---|
| Specialist crew (2-person), 2 days at £600/day (equipment-inclusive) | £1,200 |
| Skip/waste disposal for extracted fibre | £220 |
| Borescope survey (pre- and post-extraction, rolled into the job) | £120 |
| Subtotal — cost | £1,540 |
| Margin at 30% | £462 |
| Quoted price to customer | £2,002 |
That £2,002 sits comfortably in the extraction-only band (£1,800–£3,500), toward the lower-middle as you'd expect for a straightforward job with good access and no bonded bead to fight through. A harder job on the same size property — bonded EPS bead, poor access, more holes to point in old handmade brick — pushes labour to 3 days at £650/day, materials to £400, giving a cost of £2,350 and a quoted price around £3,055 at the same 30% margin — still within the band, correctly positioned toward the top.
Reconciling the combined extraction + refill figure: if the same customer decides, after extraction, to refill the cavity with EPS bead rather than leave it empty, that refill is priced as its own job using the same method as a fresh CWI install (see cavity wall insulation pricing guide) — for an 80m² 3-bed semi that lands around £1,350. Add that to the £2,002 extraction quote and the full remediation totals £3,352 — inside the combined-scope band of £2,500–£5,500, and correctly higher than either the extraction alone (£2,002) or the refill alone (£1,350). This is the check every estimator should run before sending a "package" quote: the combined price must never come out cheaper than either individual component, because you are doing both pieces of work, not choosing between them.
Why extraction costs more than new installation
Customers who've had a neighbour's CWI blown in for a few hundred pounds under a grant scheme are routinely surprised that extraction from their own house costs several times more. Three reasons:
- No grant funding. ECO4 and GBIS subsidise new installation because it reduces carbon emissions; nothing subsidises extraction. The full cost lands on the customer or, where applicable, on CIGA's claim budget.
- Specialist equipment. A powered vacuum extraction unit is a different (and less common) piece of kit than the blowing-in machine used for installation, and fewer contractors carry it — less competition, higher day rates.
- The job is inherently slower. Extraction has to work methodically to avoid leaving pockets of material behind, followed by a borescope check and full making-good of every hole — more time than the injection-only process of installation.
Pricing the making-good properly
Pointing is where estimators most often underquote. A standard 3-bed semi extraction job involves 40–70 drilled holes depending on wall area and drill pattern (roughly 1,000mm horizontal, 450mm vertical, staggered). At £6–£12 per hole in materials and skilled time — more at the top end for colour-matched mortar on older or unusual brick — that's £240–£840 just in making-good, which is why it needs to be an explicit line in the quote rather than an assumed inclusion. Poorly colour-matched pointing is the defect customers notice first and complain about loudest, so this is not the place to shave time.
PUR foam: pricing the alternative, not the removal
Cured polyurethane foam cannot be mechanically extracted — see cavity wall insulation removal guide for why. This changes the entire pricing conversation: instead of quoting extraction, you're quoting a symptom-management job.
Typical PUR foam remediation, 3-bed semi:
- Silicone masonry cream application (breathable, reduces rain penetration): £900–£1,600 for a full elevation or two
- Or specialist breathable render to the worst-affected elevation: £1,800–£2,800
- Guttering, flashing and DPC-level detailing checks/repairs (often bundled in as these compound the problem): £150–£500
Set expectations before booking a survey — a customer who's been told "cavity wall insulation removal" by a surveyor or lender, and who actually has PUR foam, needs to understand extraction isn't on the table at any price, and what the realistic alternative costs and achieves.
Regional variation
Extraction contractor day rates track general specialist trade rates: £380–£450/day in most of the UK, £450–£550/day in London and the South East. Because the specialist extraction plant is less widely held than standard tools, some regions have fewer contractors able to do this work at all, which can push prices up independent of the general regional cost-of-labour pattern — check local availability before assuming a "cheap region" discount applies.
Red flags that push the price to the top of the band
- Bonded EPS bead — adhesive bonding means the bead has to be broken up as it's extracted; budget 30–40% more time than loose fill.
- Poor or restricted access — gable ends, bay windows, and elevations behind later extensions need extra access holes and sometimes scaffolding or towers, adding a separate line.
- Compacted or bridged material — visible on the pre-survey borescope; means slower extraction and a higher chance of needing supplementary holes.
- Older or unusual brick — colour-matching mortar on handmade or reclaimed brick is genuinely skilled and slow work; price it as such, don't fold it into a generic pointing allowance.
- Wet cavity requiring a drying-out period before reinstatement — doesn't add direct cost but extends the programme, which matters for fixed-price quotes with a completion date attached.
- Live CIGA claim — if a guarantee claim is in progress, don't quote against it; CIGA's appointed contractor and pricing framework take over, and duplicating that route wastes the estimate.
What to itemise on the quote
- Borescope survey (and whether the fee is credited against the job)
- Extraction — day rate, number of crew days, fill type assumed
- Skip/waste disposal
- Pointing/making-good — number of holes assumed, mortar match approach
- Wall tie inspection, if included
- Reinstatement (refill or leave empty) as a clearly separate line with its own price, not folded silently into the extraction figure
- Access equipment (scaffold, tower) if required
- Whether the job is being quoted against an active CIGA claim or as a private job
Frequently Asked Questions
Why is extraction so much more expensive than the original installation was?
Because installation was very likely grant-subsidised (ECO4, GBIS, or an earlier scheme) and extraction never is. There's also less competition among contractors who carry vacuum extraction equipment, and the job takes longer per square metre than blowing fill in. Comparing the two prices directly is comparing a subsidised job to an unsubsidised one, not like-for-like labour costs.
Should I quote extraction and refill as one combined price, or two separate quotes?
Two clearly itemised lines within one document is usually best practice. Combining them into a single undifferentiated figure makes it hard for the customer to understand what they're paying for, and makes it harder for you to defend the price if they later ask why refilling wasn't just "included." Show extraction as one line and reinstatement (refill, or leave-empty at no extra materials cost) as a separate decision with its own price.
Can I offer a discount for doing extraction and refill together?
You can offer a modest discount for a single mobilisation (one visit, one set-up, slightly reduced overall time) — but the combined price should still exceed either job done alone. If your "bundle" price comes out lower than the extraction-only price, you've made a pricing error, not a good deal for the customer; check the arithmetic before sending the quote.
What should I quote if the customer just wants a survey to see if extraction is even needed?
Price the borescope survey as its own product (£150–£300) with a clear statement of what happens to that fee if the customer proceeds to book the extraction — most contractors credit it against the job. Don't quote a full extraction price speculatively before a survey has confirmed fill type, extent, and access — you'll either underquote a harder-than-expected job or lose the work to a competitor who priced the survey honestly.
Regulations & Standards
BS 8208-1:1985 (withdrawn 2009) — Guide to assessment of suitability of existing cavity walls for filling with thermal insulants; withdrawn as a formal standard but still widely referenced by surveyors for its assessment criteria — treat as historical good-practice guidance, not a current compliance document. For current thermal-performance requirements use Building Regulations Approved Document L below
CIGA (Cavity Insulation Guarantee Agency) — 25-year guarantee scheme; where a claim is live, CIGA's own pricing and contractor framework applies instead of an open-market quote
Building Regulations Approved Document L — relevant if reinstatement changes the wall's thermal performance
CDM 2015 — Construction (Design and Management) Regulations; notifiable for most extraction jobs involving access equipment and dust
HMRC VAT Notice 708/6 — Energy-saving materials zero rate; applies to new CWI installation, not to removal/remediation work, which is standard-rated at 20%
CIGA: What You Need to Know — guarantee scheme information, claims and approved contractor network
Energy Saving Trust: Cavity Wall Insulation — consumer guidance including problem cases
Which? CWI Guide — independent consumer assessment including failure and remediation cases
GOV.UK — VAT Notice 708/6: energy-saving materials — zero-rating rules for new installation vs standard-rated removal
HSE — CDM 2015 guidance — notifiable work requirements
cavity wall insulation removal guide — the extraction process, CIGA claim route and reinstatement options in technical detail
cavity wall — CWI suitability, exposure zones and why fill fails in the first place
cavity wall insulation pricing guide — pricing for fresh/reinstatement CWI installation, used as the basis for the refill figures above
external wall insulation — the alternative where a wall can't reliably take any cavity fill