"How much will this cost?" is always the first question — and it's a fair one. Subsidence repair costs vary enormously depending on the method, the severity, and the specific property. This guide gives you realistic figures based on actual projects we've completed across Hertfordshire, so you can plan with confidence.
Cost by Repair Method
| Method | Typical Cost Range | Duration | Best For |
|---|---|---|---|
| Resin injection | £3,000–£8,000 | 1 day | Clay shrinkage, minor-moderate subsidence |
| Traditional underpinning | £10,000–£30,000+ | 2–8 weeks | Severe subsidence, deep foundation issues |
| Void filling | £2,000–£6,000 | 1–2 days | Underground voids, washout, old drains |
| Slab lifting | £1,500–£5,000 | Half day–1 day | Sunken concrete slabs, driveways, floors |
| Foundation repair (combined) | £5,000–£20,000 | 1 day–6 weeks | Complex cases needing multiple methods |
What Affects the Price?
Not all subsidence is equal. The same method can cost very different amounts depending on:
Severity of movement — a corner that's dropped 5mm needs far less treatment than one that's dropped 30mm. Greater movement generally means more material, more injection points, or deeper underpinning.
Length of affected wall — underpinning is priced per metre run. A 3m section is a very different job from a 12m section.
Access — can we get equipment to the affected area? Properties with narrow side passages, conservatories blocking access, or basement-level foundations cost more to work on.
Ground conditions — the type and depth of soil, the presence of ground water, and the proximity of trees all affect the complexity and cost.
Property type — larger properties, period buildings, and commercial premises typically cost more due to scale and structural complexity.
Real Examples from Hertfordshire
These are genuine project costs (anonymised) from recent work:
| Property | Location | Issue | Method | Cost |
|---|---|---|---|---|
| 3-bed semi | Watford | Corner subsidence, clay shrinkage | Resin injection | £4,800 |
| Victorian terrace | St Albans | Settlement due to shallow foundations | Resin injection + monitoring | £6,200 |
| 4-bed detached | Harpenden | Severe subsidence from oak tree | Underpinning (6m) | £18,500 |
| Warehouse floor | Stevenage | Sunken concrete slab | Slab lifting | £3,400 |
| 1930s semi | Potters Bar | Void beneath extension | Void filling | £3,800 |
| Edwardian semi | Hitchin | Cracking due to drain leak + clay | Drain repair + resin injection | £7,100 |
Insurance: Who Pays?
Most buildings insurance policies cover subsidence damage. If your claim is accepted, the insurer pays for:
- All structural repairs
- Cosmetic reinstatement (replastering, decorating)
- Professional fees (surveys, engineering)
You pay the subsidence excess, which is typically £1,000 (compared to the standard excess of £100–£250 for other claims). Some policies have higher excesses — check your policy wording.
Important: If your property has a history of previous subsidence claims, insurance can be more expensive or harder to obtain. Specialist insurers exist for this purpose, and premiums have become more competitive in recent years.
For a full guide to the claims process, see our article on making a subsidence insurance claim.
Getting an Accurate Quote
Every property and every subsidence case is unique. The figures above are guidelines — the only way to get an accurate cost for your specific situation is through a professional site survey.
We offer free surveys with no obligation across all of Hertfordshire. After the survey, you'll receive a fixed-price quote — not an estimate — so you know exactly what the work will cost before deciding to proceed.
What the quote includes: - All materials and labour - Survey and engineering - Post-treatment monitoring - Structural certification - Clean-up and making good
What it doesn't include: - Cosmetic decoration (replastering, repainting) — though we can recommend trades - Tree management — we'll advise on what's needed, but tree work is carried out by specialist arborists
Is It Worth Getting Multiple Quotes?
Yes, but compare like with like. A lower quote that doesn't include monitoring or certification may end up costing more in the long run — particularly if you're selling the property or making an insurance claim, where documentation is essential.
Look for: - Fixed price, not estimate — you want certainty - Inclusions clearly stated — survey, materials, monitoring, certification - Warranty — what guarantee comes with the work? - Insurance — is the contractor properly insured for structural work?