The short answer
Underpinning often shows up on a survey, and even where the physical work is hidden underground, the history usually surfaces through other channels. A RICS surveyor looks for tell-tale signs of past movement and repair — patched cracks, replaced brickwork, areas of newer render, and floor or wall distortion — and will flag where a property appears to have been underpinned or to have a movement history. Beyond the survey itself, underpinning is commonly recorded in building-control records, comes up in insurance enquiries and claims history, and must be declared by the seller on the TA6 form. Because these sources cross-check each other, attempting to conceal underpinning rarely succeeds — and a surveyor who spots signs of movement will usually recommend a structural engineer's inspection to confirm whether the foundations are now stable.
Buyers often ask whether a survey will reveal past underpinning, and sellers sometimes hope it won't. The sections below explain what a surveyor can and can't see, the other records that capture underpinning, and why disclosure beats concealment.
Detection at a glance
- Surveyor spotsPatched cracks, new brickwork, render
- Survey levelRICS Level 2 or 3
- Also recorded inBuilding control records
- Surfaces viaInsurance & claims enquiries
- Seller must declareYes — on the TA6 form
What a surveyor actually looks for
Underpinning is below ground, so a surveyor will not usually see the concrete itself during a standard, non-intrusive survey. What they do see are the signs of past movement and the repairs that follow underpinning:
- Repaired cracks — filled or stitched cracks, especially diagonal ones near openings, that hint at previous movement.
- Replaced or re-pointed brickwork and patches of newer mortar where damage was made good.
- Fresh render or plaster over older surfaces, sometimes covering repaired cracking.
- Distortion — out-of-square door and window frames, sloping floors, or a section of wall that has clearly moved and been corrected.
A more detailed RICS Level 3 Building Survey goes further than a Level 2 Homebuyer survey and is more likely to identify and comment on a movement history, recommending further investigation where signs are present.
The other places underpinning is recorded
Even if a survey is inconclusive, underpinning is typically discoverable through the wider conveyancing process:
| Source | What it reveals | Who checks it |
|---|---|---|
| TA6 Property Information Form | Seller's declared movement history | Buyer's solicitor |
| Building control records | Approved underpinning works | Solicitor / local authority search |
| Insurance enquiries | Past subsidence claims | Buyer's insurer / solicitor |
| Guarantee registers | Contractor warranty on file | Solicitor |
| Structural engineer report | Confirms work and stability | Buyer (if commissioned) |
Indicative summary of where underpinning is recorded and who reviews each source.
What the survey types cover
Not all surveys probe to the same depth, which affects how likely each is to flag underpinning or past movement:
- Mortgage valuation: commissioned by the lender for its own purposes, this is a brief check of value and basic condition, not a survey for the buyer. It may note obvious problems but is not designed to investigate movement.
- RICS Level 2 (HomeBuyer) Survey: a mid-level survey suitable for conventional properties in reasonable condition. It will comment on visible defects and may flag obvious signs of movement, prompting further enquiry.
- RICS Level 3 (Building) Survey: the most detailed standard survey, recommended for older, larger or altered homes. It examines the property thoroughly and is the most likely to identify and discuss a movement history and recommend a structural engineer where needed.
None of these is intrusive — surveyors do not dig up foundations — so even a Level 3 survey detects underpinning through the above-ground signs and the surveyor's judgement rather than by uncovering the concrete itself. For full certainty about the foundations, a focused structural engineer's inspection is the next step.
Why you can't easily hide it — and shouldn't try
The combination of these sources makes underpinning hard to conceal. A surveyor may spot the physical signs; building-control records and insurance history provide a paper trail; and the seller is legally obliged to disclose it on the TA6, where a false answer risks a misrepresentation claim. Even cosmetic concealment — fresh paint over repaired cracks — tends to look 'too new' to an experienced surveyor and invites closer scrutiny. For sellers, this means there is little to gain and much to lose from hiding underpinning: the most likely outcomes are a collapsed sale once it surfaces, or a claim after completion. The better approach for everyone is transparency: a seller who provides the Certificate of Structural Adequacy, building-control sign-off and guarantees turns a potential survey 'red flag' into a documented, reassuring history. For buyers, if a survey mentions any sign of movement or possible underpinning, follow it up with the seller's documents and, if needed, a structural engineer.
Frequently asked questions
Can a surveyor see underpinning underground?
Not directly in a standard, non-intrusive survey, because the underpinning is beneath the foundations. What a surveyor sees are the above-ground signs of past movement and repair — patched cracks, replaced brickwork, fresh render and distortion — which prompt them to flag a likely movement history and recommend further investigation.
Which survey is most likely to detect underpinning?
A RICS Level 3 (Building) Survey is the most detailed standard survey and is the most likely to identify and comment on signs of movement or underpinning. A Level 2 Homebuyer survey may still note obvious signs but is less thorough. Where movement is suspected, a structural engineer's inspection gives the clearest picture.
Will the seller have to tell me about underpinning?
Yes. In England and Wales the seller must answer the TA6 Property Information Form truthfully, which asks about structural movement, subsidence and related works. Combined with building-control records and insurance enquiries, this means underpinning is normally disclosed and verifiable during conveyancing.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.