Survey Red Flags: 15 Findings Ranked by Real Repair Cost

Your surveyor's job is to rate the condition of each part of the house, and a good survey flags clearly what needs attention. Pricing the repairs isn't part of that job, so a £180 gutter repair and a full re-roof can both get a red Condition Rating 3. That's where a builder can add practical repair costs and next steps.

I'm Ben Murrell, a builder with nearly 30 years on site. Below are 15 findings that come up again and again in RICS surveys, ranked from the most expensive to the least, using the same typical ranges as our other cost guides.

Please read these as typical ranges, not quotes. Real costs depend on the size, age and construction of the house, access, and where you are. In London and the South East, expect to be towards the top of a range. The only way to get a firm number is a contractor's quote or a specialist's report.

A list can't tell you which repair your house needs. In a £59 independent survey review, I'll read the actual findings and any specialist reports, put realistic ranges against the work described and explain what needs investigating first. You get a personal email from me and a call within 24 hours. See the example review.

The 15 red flags, most expensive first

Smaller items that often appear alongside these: chimney repointing and flashings (£900 to £3,500), an old boiler with no service record (£2,400 to £4,200) and a consumer unit with no RCD protection (£700 to £1,500).

For a rough starting budget, use the survey repair cost calculator. To see how I turn findings into costs and next steps for a client, read what my survey review emails look like.

What each one usually means

1. Subsidence needing underpinning. The big one, though confirmed subsidence is uncommon and many movement notes turn out to be old, stable settlement. If the surveyor recommends an engineer, get that report before exchange; it often costs £500 to £1,200 and turns the surveyor's recommendation into a clear decision. See underpinning costs.

2. Dry rot. Serious because it spreads through masonry as well as timber. The range is wide because you don't know how far it goes until floors and plaster come off. Wet rot vs dry rot.

3. Rotten windows. One or two rotten sills can be spliced; a whole house of failed sashes is a big bill. Repair or replace?

4. Roof covering. "Nearing the end of its serviceable life" means plan for it, not that it leaks tomorrow. Ask a roofer whether repairs buy a few years. Ageing roof coverings.

5. Rewire. Old rubber or fabric cable is a real flag. A rewire is much easier before you move in. Ask the seller for an EICR.

6. Japanese knotweed. Mostly a mortgage and management issue. You need a specialist's plan, and often an insurance-backed guarantee. Knotweed guide.

7. Wall tie failure. Horizontal cracks in the mortar every few courses on cavity walls are the tell-tale sign. It's fixable, but needs a specialist survey.

8. Rising damp. Where the surveyor flags damp, the next step is finding the cause. It is often high ground levels, bridged DPCs, leaks or condensation. Find the cause before anyone sells you an injected DPC. Rising vs penetrating damp.

9. Drains. A CCTV drain survey (typically £200 to £400) is one of the best-value checks before exchange.

10. Repointing. Cost depends on scaffolding and on using the right mortar. Hard cement pointing on soft old brick is a common cause of damp in older houses.

11. Flat roofs. Extensions and dormers. Felt has a shorter life than modern membranes. Flat roof findings.

12. No building regs sign-off. The cost is anything from a regularisation application to opening up work for inspection. Talk to your solicitor before contacting the council. Missing sign-off.

13. Chimney stack rebuild. Leaning or badly eroded stacks. Scaffolding is a big part of the cost. Chimney stacks and flashings.

14. Penetrating damp. Usually a gutter, downpipe, render or pointing problem. Fix the cause and the damp goes.

15. Lintels. Cracks rising from window corners. Usually one opening, sometimes several. Lintel problems.

How to use this list

This page compares defects; it doesn't decide their urgency on your house. For the order to tackle the report, use what to do after your survey.

1. Sort first. Separate what you knew at the viewing from what you didn't. Only the second group is fair negotiation material.
2. Price the urgent items. Use the ranges above as a sense check, then get quotes or specialist reports where the number is big.
3. Don't use the top of every range. A schedule that assumes the worst on everything isn't credible.
4. Then decide: proceed, renegotiate, or walk. See how much you can negotiate off after a survey and, if the seller says no, your five options.