The biggest issues that are flagged on a house survey
Buying a property can be exciting, but getting a house survey back can feel a bit overwhelming, especially when it highlights problems you might not have expected. It can make you feel like you’ve spent money for no reason, but remember, the survey has helped you protect a much larger portion of your investment.
So, if you’ve had a survey back and want to know what you should actually worry about, here are the most common red flags, what they mean and the action you should take.
Quick answer overview:
Common house survey red flags include:
- Structural movement or subsidence
- Damp and water ingress
- Roof defects
- Electrical problems
- Unapproved alterations
- Japanese knotweed
- Drainage issues
- Asbestos
Understanding what is meant by a red flag
Level 2 and Level 3 surveys are graded using a traffic light system. They work as follows:
- Condition Rating 3 (red) = serious and/or urgent defects
- Condition Rating 2 (amber) = needs repairing or replacing, but not serious or urgent
- Condition Rating 1 (green) = no repair currently needed
The biggest red flags are those rated as Condition Rating 3.
Breaking down the red flags
| Issue | What the Survey Might Show | Risk Level | Why It Matters |
|---|---|---|---|
| Structural movement / subsidence | Cracks (often diagonal), uneven floors, and sticking doors/windows | High | Can indicate serious structural instability, expensive underpinning, and potential mortgage issues |
| Damp and water ingress | Rising damp, penetrating damp, leaks, mould | Medium–High | Can damage walls, timber, and plaster; may signal hidden leaks or ventilation problems |
| Roof problems | Missing/slipped tiles, sagging roof structure, poor repairs | High | Risk of major water ingress leading to widespread internal damage |
| Electrical issues | Old wiring, outdated fuse boards, unsafe DIY electrics | Medium–High | Fire risk and likely need for full or partial rewiring |
| Unapproved alterations | Missing building regs, removed load-bearing walls, and loft conversions without certification | High | Legal and safety risk may affect resale and mortgage approval |
| Japanese knotweed | Presence near or within the boundary | High | Can damage foundations and is difficult/expensive to remove; mortgage lenders may refuse to lend |
| Tree-related subsidence risk | Large trees close to the property, evidence of root impact | Medium–High | Roots can affect soil stability and cause structural movement over time |
| Drainage problems | Blocked drains, slow runoff, and damaged underground pipes | Medium | Can lead to flooding, damp issues, and costly excavation/repairs |
| Asbestos (older properties) | Found in ceilings, insulation, and garage roofs | Medium | Health risk if disturbed; removal requires specialist contractors and can be costly |
| General poor maintenance | Multiple small defects, neglected upkeep, and ageing systems | Medium | Indicates higher ongoing repair costs and potential hidden deeper issues |
Actions to take if red flags appear
First things first, don’t panic, but don’t ignore them. You’ve got a few options: get a specialist report, such as one from a structural engineer or a damp survey; renegotiate the price if you still wish to proceed; ask the seller to address and fix the issues; or simply walk away if the risks are too high.
Buying in Surrey or London? Request a survey quote from Westville Associates.
A £1,000 problem is very different to a £30,000 one.
Sometimes, red flags are deal breakers, such as structural issues or subsidence. But they’re not always necessarily worth walking away from. Many older properties will have issues. The key is understanding the severity, the cost to fix and the impact on value and safety. It’s understanding the difference.
So, while it might not mean “don’t buy,” it does mean to look closely before you commit.
For a Level 2 or Level 3 survey in Surrey or London, contact Westville Associates.
