A property survey can throw up a long list of defects — but most of what surveyors find falls into the same ten categories. Understanding what each one means, how serious it is, and what it typically costs to fix helps you respond to a survey report with confidence, not panic.
This guide covers the ten most common defects flagged in Level 2 and Level 3 surveys — and what you should do when your surveyor flags one.
1. Damp and moisture problems
Severity: Moderate to serious depending on cause and extent
Damp is the most frequently flagged defect in UK property surveys. It appears in three main forms: rising damp (moisture travelling up from the ground through masonry), penetrating damp (water getting in through the roof, walls, or around windows), and condensation damp (poor ventilation causing moisture to build up internally).
Signs include tide marks on lower walls, peeling paint, mould growth, or a persistently musty smell. A surveyor will rate the severity, identify the likely source, and advise on treatment.
Typical 2026 repair cost: £300–£5,000+ depending on cause and extent. Condensation issues can be resolved cheaply; rising damp requiring a new DPC and replastering is at the higher end.
What to do: Get a specialist damp survey before committing. Identify the cause precisely — damp treatment applied to the wrong type of damp is money wasted.
2. Cracks in walls
Severity: Cosmetic to structural — the width, pattern, and location determine which
Most properties have some cracks, and most are harmless. Hairline cracks in plaster are almost always cosmetic settling. The cracks that matter are wider than 5mm, diagonal, pass through brickwork rather than just plaster, or are associated with sticking doors and sloping floors.
A surveyor will classify cracks on a scale from 1 (cosmetic) to 5 (very severe structural damage). Cracks rated 3 and above typically indicate active movement and warrant investigation by a structural engineer.
Typical 2026 repair cost: £200–£500 for cosmetic; £5,000–£50,000+ for underpinning if subsidence is confirmed.
What to do: Don’t dismiss crack ratings. Read our guide to structural damage warning signs to understand what distinguishes minor movement from something more serious.
3. Roof defects
Severity: Moderate to serious — roof problems worsen quickly if unaddressed
Roof defects are among the most expensive findings on older properties. A surveyor will inspect from the loft space (where accessible) and externally. Common findings include slipped, cracked, or missing tiles; failed ridge pointing; defective flashings at chimneys and valleys; sagging roof structure; and inadequate or absent insulation.
Even a minor leak, if left, leads to saturated roof timbers, rot, and eventually structural damage to the rafters and joists.
Typical 2026 repair cost: £200–£1,500 for isolated tile repairs and repointing; £8,000–£25,000+ for partial or full re-roof.
What to do: Obtain a quote from a roofing contractor before exchange. A written quote gives you solid grounds to renegotiate the purchase price.
4. Faulty drainage
Severity: Moderate — often hidden until it causes damp or foundation issues
Blocked, cracked, or misaligned drains are common in older properties and are often invisible without a CCTV drain survey. Surveyors will note evidence of drainage problems such as wet ground near the house, damp to lower walls, or visible defects to gullies and inspection chambers — but they won’t camera the drains themselves.
Typical 2026 repair cost: £150–£600 for jetting and minor repairs; £2,000–£10,000+ for excavation and pipe replacement.
What to do: If your surveyor flags drainage concerns, commission a CCTV drain survey (typically £100–£300) before exchange. It’s one of the highest-value additional checks you can do.
5. Defective windows and doors
Severity: Low to moderate — important for energy efficiency and security
Surveyors frequently flag failed double-glazing seals (showing as misting between the panes), rotting timber frames, ill-fitting doors and windows (which can indicate structural movement), and single-glazed windows in otherwise modernised properties. While rarely critical to the purchase, these defects add up in repair cost and affect energy performance.
Typical 2026 repair cost: £75–£200 per sealed unit replacement; £300–£800 per window for full replacement; £5,000–£15,000 for whole-house double glazing.
What to do: Count the affected units and get a trade quote. Use the total as a price reduction request rather than a reason to pull out.
6. Electrical deficiencies
Severity: Serious where wiring is dated — a safety and insurance issue
Surveyors are not electricians and cannot test circuits, but they will flag visible signs of outdated or unsafe electrical installations — rubber-insulated wiring, old-style fuse boards without RCDs, sockets that don’t meet current standards, or evidence of DIY electrical work. An EICR (Electrical Installation Condition Report) from a certified electrician gives the full picture.
Typical 2026 repair cost: £300–£600 for a consumer unit upgrade; £3,000–£8,000+ for a full rewire depending on property size.
What to do: Commission an EICR before exchange if the surveyor flags any electrical concerns. Some mortgage lenders and insurers require a satisfactory EICR on older properties.
7. Plumbing defects
Severity: Moderate — older systems can hide significant costs
Common survey findings include lead pipework (present in many pre-1970 properties), old-style tanks in loft spaces, evidence of past leaks (staining to ceilings or floors), low water pressure, and boilers that are at or beyond end of life. As with electrics, surveyors identify visible concerns but recommend specialist inspection for detailed assessment.
Typical 2026 repair cost: £150–£400 for minor pipe repairs; £2,500–£5,000 for a new boiler and controls; £4,000–£12,000 for a full replumb.
What to do: Check the boiler age and service history. A boiler over 10–12 years old is approaching end of life — factor replacement into your offer.
8. Poor insulation
Severity: Low — but financially significant over time
Many homes built before the 1990s have little or no loft insulation, and solid-walled properties have no cavity to insulate without external or internal wall insulation. Surveyors will note the visible insulation provision and flag gaps. EPC ratings are increasingly relevant to mortgage lending, making this a growing issue for older stock.
Typical 2026 improvement cost: £300–£600 for loft insulation; £8,000–£20,000 for solid wall insulation (external or internal).
What to do: Check the current EPC rating and what measures are recommended. Government grants are available for some insulation upgrades — check current Ofgem and local authority schemes.
9. Structural movement
Severity: Potentially serious — requires specialist assessment before proceeding
Structural movement covers a range of conditions including subsidence (downward movement of foundations), heave (upward movement, often caused by clay soils drying or wetting), differential settlement, and lateral movement. Signs include stepped diagonal cracks at window and door openings, gaps between the building and extensions, and floors or ceilings that slope noticeably.
A Level 3 Building Survey is strongly recommended where structural movement is suspected — a Level 2 will flag the issue but won’t provide the depth of analysis needed to assess cause or remedy.
Typical 2026 repair cost: £500–£2,000 for monitoring; £5,000–£50,000+ for underpinning; costs vary widely based on soil type, extent, and access.
What to do: Do not exchange on a property with active structural movement without a structural engineer’s report and a clear understanding of the proposed remedy and its warranty.
10. Timber defects — rot and woodworm
Severity: Moderate to serious depending on location and extent
Timber defects are split into two categories: fungal decay (wet rot and dry rot) and insect attack (most commonly woodworm). Wet rot is localised and typically follows a moisture source — fix the leak and treat the timber. Dry rot is more serious: it spreads behind plaster and through masonry, and eradication requires removing all affected timber and treating surrounding masonry.
Woodworm (active flight holes in roof timbers, floor joists, or staircase timbers) is common and treatable, but structural timbers with significant attack need assessment by a structural engineer.
Typical 2026 repair cost: £500–£2,000 for wet rot treatment and localised replacement; £3,000–£30,000+ for dry rot eradication in an older property.
What to do: Get a specialist timber and damp survey if your surveyor flags active dry rot. Obtain a guarantee for any treatment carried out — this is transferable to you as the new owner.
What to do when your survey flags a defect
Finding defects in a survey doesn’t mean you should walk away — it means you have information your surveyor’s report gives you the basis to act on. Most buyers use survey findings in one or more of three ways:
- Price renegotiation: Obtain repair quotes and ask the vendor to reduce the asking price accordingly. A written quote carries far more weight than an informal estimate.
- Remedial work as a condition: Ask the vendor to carry out specific repairs before exchange, with evidence of completion and any relevant guarantees.
- Informed decision to withdraw: For serious structural issues without a clear and costed remedy, the report gives you the professional basis to withdraw before exchange.
Understanding which survey level is right for your property determines how much detail you’ll have available to negotiate with.
Frequently asked questions
What is the most common defect found in a house survey?
Damp is the most frequently flagged defect in UK property surveys, appearing in some form in the majority of older properties. It ranges from minor condensation that can be resolved with better ventilation, to rising or penetrating damp requiring professional treatment and replastering.
Do most houses fail a survey?
Surveys don’t pass or fail properties — they report on condition. Almost every property survey will note some defects. What matters is the severity rating and the estimated cost to remedy. Most findings are manageable and can be addressed through price negotiation or vendor repairs.
How much does it cost to fix defects found in a house survey?
Total repair costs vary enormously depending on the type and extent of defects. Minor issues such as failed window seals, cosmetic cracks, and insulation gaps might total £500–£3,000. Significant structural movement, dry rot, or a full roof replacement could reach £20,000–£50,000+. Your surveyor’s report will indicate urgency and recommend specialist assessment where costs are uncertain.
Should I pull out if a house survey finds problems?
Not necessarily. The vast majority of survey findings are negotiating tools, not reasons to withdraw. Use the report to request a price reduction or vendor repairs before exchange. Only defects with no clear and affordable remedy — such as confirmed active subsidence or widespread dry rot in a listed building — typically justify withdrawal.
Will a Level 2 survey pick up all these defects?
A Level 2 survey will identify and rate visible defects but does not investigate causes in depth or provide detailed structural analysis. For older properties, non-standard construction, or where the Level 2 flags significant concerns, a Level 3 Building Survey gives you the full picture.
How we can help
At Lyman Marshall Chartered Surveyors, we carry out Level 2 and Level 3 Building Surveys across Lincolnshire, Nottinghamshire, Humber, and South Yorkshire. Explore our full range of survey services to see how we can help. Our reports are written in plain English, rated clearly by severity, and tailored to the specific property — not a generic template.
- RICS Chartered Surveyors
- Fixed fees quoted upfront
- Reports within 3–5 working days
- Local team covering the East Midlands, Lincolnshire & Humber
Book your survey:
- Call: 01522 438989
- Email: hello@lmsurveyors.co.uk
- Online: Request a quote
