After conducting thousands of building surveys across Hammersmith, Fulham, Ealing, Chiswick, and Richmond, we've identified patterns in property defects specific to West London. At West London Surveyors, our RICS chartered surveyors have inspected everything from grand Victorian villas to modern apartment blocks, and we know exactly what issues affect properties in this area.
This comprehensive guide reveals the 10 most common defects we encounter, complete with photos, typical repair costs, warning signs, and prevention strategies. Understanding these issues before you buy can save you tens of thousands of pounds.
Of West London properties surveyed have at least one defect requiring attention
Average cost of repairs for properties with multiple defects
Average savings achieved through price negotiation after survey
1. Subsidence and Structural Movement
Frequency: Found in approximately 15% of properties surveyed, particularly Victorian and Edwardian properties built on London clay.
What Causes Subsidence in West London?
West London sits on London clay, which shrinks when dry and expands when wet. This seasonal movement causes foundations to shift. The main triggers include:
- Tree root activity - Mature trees (especially poplars, oaks, willows) extracting moisture from clay soil
- Drainage leaks - Water washing away soil beneath foundations
- Shallow foundations - Victorian properties often built on foundations only 2-3 feet deep
- Clay soil shrinkage - Hot, dry summers causing significant ground movement
- Vegetation removal - Removing large trees or hedges allowing soil to re-hydrate and heave
Warning Signs:
- Diagonal cracks wider than 5mm, especially near corners
- Cracks wider at top than bottom (or vice versa)
- Bay windows pulling away from main walls
- Doors and windows sticking or not closing properly
- Visible step pattern cracks following brick courses
- Rippling or sloping floors
Repair Costs
Minor monitoring: £500-£1,000 per year
Underpinning (small area): £10,000-£15,000
Underpinning (whole terrace front): £25,000-£40,000
Structural repairs + decoration: Add 20-30%
Prevention & Management:
Maintain trees at safe distances (minimum 1.5x mature height from property). Ensure good drainage around foundations. Regular monitoring of existing cracks. Install crack monitoring strips (£50-£100 per strip). Act quickly if movement is progressive.
2. Rising and Penetrating Damp
Frequency: Present in 40% of Victorian/Edwardian properties, making it the most common defect we encounter.
Types of Damp in West London Properties:
Rising Damp
Ground moisture rising through walls without proper damp proof courses (DPC). Victorian properties were built without DPCs, and many retrofitted DPCs have failed.
Signs: Tide marks up to 1 meter high, peeling paint/wallpaper at low level, salt deposits (efflorescence), musty smell, damaged skirting boards.
Costs: Chemical DPC injection: £1,500-£4,000 depending on wall length. Replastering affected walls: £1,500-£3,000. Total typical cost: £3,000-£7,000.
Penetrating Damp
Water entering through walls, especially around bay windows, parapet walls, and failed pointing.
Signs: Damp patches on walls after rain, staining around windows, mould growth, peeling external render.
Costs: Repointing walls: £40-£60 per m². Bay window repairs: £2,000-£5,000. Render repairs: £3,000-£8,000.
Condensation
Water vapor condensing on cold surfaces due to poor ventilation, especially common in solid-walled Victorian properties.
Signs: Black mould on walls/ceilings, condensation on windows, damp smell without tide marks.
Costs: Ventilation improvements: £500-£2,000. Insulation: £4,000-£12,000 for external wall insulation.
Common Misdiagnosis
Many damp specialists misdiagnose condensation as rising damp and sell unnecessary DPC treatments. Always get a surveyor's opinion before committing to damp work. West London Surveyors uses moisture meters and thermal imaging to accurately identify damp sources.
3. Roof Problems
Frequency: 35% of properties have some level of roof defect, from minor repairs to complete replacement needed.
Common Roof Issues:
| Defect | Typical Cost | Urgency |
|---|---|---|
| Slipped/missing slates (5-10) | £500-£1,200 | Medium |
| Failed valley gutters | £2,000-£4,000 | High |
| Chimney stack repairs | £1,500-£4,000 | Medium-High |
| Lead flashing replacement | £1,000-£2,500 | Medium |
| Full slate roof replacement | £15,000-£25,000 | Medium (if no leaks) |
| Flat roof replacement (rear extension) | £3,000-£6,000 | High if leaking |
Warning Signs from Ground Level:
- Slipped or missing tiles/slates visible from street
- Sagging roofline or ridge
- Vegetation growing from gutters or tiles
- Cracked or leaning chimney stacks
- Water stains on ceilings inside
- Daylight visible through roof from loft
Roof Lifespan in West London
Welsh slate (original): 100-150 years
Clay tiles: 60-100 years
Concrete tiles: 40-50 years
Felt flat roofs: 10-20 years
Modern GRP flat roofs: 25-30 years
Most Victorian properties in West London are 120-150 years old, meaning original roofs are at end of life even if not actively leaking.
4. Electrical Installation Issues
Frequency: 45% of properties have outdated electrical systems requiring full or partial rewiring.
Common Electrical Problems:
- Old fuse boxes - Ceramic rewireable fuses instead of modern consumer units with RCDs
- Fabric-covered wiring - Pre-1960s rubber-insulated cables that degrade and become dangerous
- Inadequate earthing - Poor or missing earth connections risking electric shock
- Insufficient sockets - Leading to dangerous overuse of extension leads
- DIY alterations - Non-compliant work not certified to Building Regulations
- Aluminum wiring - 1960s-70s wiring that's now considered hazardous
Costs:
EICR test (Electrical Installation Condition Report): £150-£300
Full rewire (3-bed Victorian terrace): £6,000-£10,000
Consumer unit upgrade only: £600-£1,200
Partial rewire (high-risk circuits): £2,500-£4,500
Electrical Safety
Mortgage lenders increasingly require EICRs for older properties. An EICR should be conducted every 10 years (or 5 years for rental properties). "Unsatisfactory" ratings can delay or prevent mortgage approval.
5. Timber Decay and Insect Infestation
Frequency: 25% of older properties show evidence of past or present timber problems.
Types of Timber Issues:
Wet Rot
Fungal decay affecting timber with moisture content above 20%. Common in ground floor joists, window frames, and roof timbers.
Treatment cost: £1,500-£4,000 including affected timber replacement and cause resolution.
Dry Rot
Serious fungal attack (Serpula lacrymans) that spreads through masonry. Less common but devastating when present.
Treatment cost: £3,000-£15,000+ depending on extent. Can require extensive timber removal and sterilization.
Woodworm (Common Furniture Beetle)
Small beetles boring through timber leaving 2mm holes. Usually old, inactive infestations but active cases require treatment.
Treatment cost: £500-£1,500 for spray treatment of accessible timbers.
Death Watch Beetle
Found in old hardwood timbers, especially in listed buildings. Creates larger 3mm holes.
Treatment cost: £2,000-£8,000 for specialist treatment.
Warning Signs:
- Musty, mushroom-like smell
- Soft, spongy timber when pressed
- Small round holes in exposed woodwork
- Fine dust (frass) beneath timber
- Fungal growth or cotton wool-like strands
- Cracking or cubing of timber surface
6. Defective Gutters and Drainage
Frequency: 30% of properties have gutter or drainage issues contributing to damp and foundation problems.
Common Issues:
- Blocked gutters - Overflowing water damaging walls (cleaning: £80-£150)
- Leaking joints - Cast iron or plastic gutters with failed seals (repair: £300-£800)
- Inadequate capacity - Original gutters too small for today's heavy rainfall (replacement: £1,200-£2,500)
- Broken downpipes - Water cascading down walls (repair: £200-£500)
- Failed drainage - Blocked or collapsed underground drains (CCTV survey + repair: £500-£3,000)
Prevention Saves Thousands
Annual gutter cleaning (£80-£150) prevents expensive damp problems costing thousands. In West London's tree-lined streets, gutters should be cleared at least twice yearly - autumn and spring.
7. Window and Door Failures
Frequency: 40% of Victorian properties have original or deteriorating windows requiring repair or replacement.
Common Window Problems:
| Issue | Repair Cost | Replacement Cost |
|---|---|---|
| Rotten sash window sills | £150-£300 per window | £800-£1,500 full replacement |
| Broken sash cords | £80-£150 per window | N/A |
| Failed double glazing units | £150-£300 per unit | £500-£800 full window |
| Rotten timber casements | £200-£400 per window | £600-£1,200 |
| Entire set (8 windows) | £2,000-£4,000 | £8,000-£15,000 |
Important Considerations:
In conservation areas (common in West London), replacement windows must match originals in style, material, and proportions. Planning permission may be required. Restoring original sash windows is often preferable to replacement and maintains property value.
8. Defective Pointing and Brickwork
Frequency: 50% of Victorian properties need repointing work within 5-10 years.
Why West London Properties Need Repointing:
Original lime mortar breaks down over 100+ years. Many properties were repointed with hard cement mortar (incorrect for old bricks), causing brick face damage. Weather exposure accelerates deterioration.
Signs of Pointing Failure:
- Crumbling mortar that can be scraped out easily
- Mortar recessed more than 10mm behind brick face
- Cracks in mortar joints
- Damp penetration at mortar joints
- Loose or spalling bricks
Costs:
Repointing (lime mortar): £40-£60 per m²
Full front elevation (typical terrace): £3,000-£5,000 including scaffold
Whole house exterior: £8,000-£15,000
Brick replacement (if needed): Add £20-£30 per brick
Lime vs Cement Mortar
Victorian bricks MUST be repointed with lime mortar, not modern cement. Cement mortar is harder than bricks, trapping moisture and causing brick faces to spall and crack. Lime mortar is breathable and flexible, protecting brickwork for another 100 years. Insist on lime mortar (NHL 3.5) for period properties.
9. Heating System Problems
Frequency: 30% of properties have boilers over 15 years old or inefficient heating systems.
Common Issues:
- Old boilers - 15+ years old, inefficient, parts unavailable (replacement: £2,500-£4,000)
- No central heating - Some Victorian conversions still lack CH (full installation: £7,000-£12,000)
- Single-pipe systems - Inefficient 1970s systems (upgrade: £3,000-£6,000)
- Lack of thermostatic controls - Wasting energy (upgrade: £800-£1,500)
- Corroded radiators - Internal corrosion reducing efficiency (powerflush: £400-£600; replacement: £150-£300 per radiator)
Modern Requirements:
New boilers must be condensing type (A-rated, 90%+ efficiency). Smart controls now standard (thermostat, TRVs, timer). Heat pump conversion becoming popular: £10,000-£18,000 including government grants.
10. Poorly Executed Alterations and Extensions
Frequency: 35% of properties have some form of undocumented or non-compliant building work.
Common Problematic Alterations:
1. Removed Chimney Breasts Without Support
Chimney breast removed from ground floor without supporting upper floor breast. Creates massive structural risk.
Remedy cost: £3,000-£8,000 for steel beam installation, building control retrospective approval, making good.
2. Knocked-Through Walls Without Adequate Support
Load-bearing walls removed or opened up without proper structural calculations or beams.
Remedy cost: £4,000-£12,000 depending on span and load.
3. Loft Conversions Without Building Regulations
Undocumented loft conversions lacking fire safety, structural integrity, or stair compliance.
Impact: Affects saleability, mortgage approval, insurance. Retrospective approval: £2,000-£5,000 if possible; removal/rebuild: £20,000-£40,000.
4. Poor Quality Extensions
Rear or side extensions with inadequate foundations, improper wall ties, or poor weatherproofing.
Remedy cost: £5,000-£20,000+ depending on severity.
5. DIY Electrical Work
Non-certified electrical alterations not complying with Part P Building Regulations.
Remedy: EICR identifies issues; remedial work £500-£3,000.
Building Regulations Compliance
Essential checks when buying:
- Request Building Regulations certificates for all extensions/conversions (post-2000)
- Ask for electrical installation certificates for work done since 2005
- Check planning permission was obtained if required (conservation areas, extensions over certain sizes)
- Verify party wall procedures were followed for relevant works
Missing documentation significantly affects property value and mortgage ability.
Area-Specific Patterns in West London
Different West London areas show distinct defect patterns based on property types and ages:
Hammersmith & Fulham
- High incidence of basement damp (properties near Thames)
- Subsidence from mature street trees
- Poorly executed loft conversions (very popular area for these)
Chiswick
- Tree root subsidence (leafy area with many mature trees)
- Original sash windows requiring replacement
- Roof issues on larger Victorian properties
Ealing
- Wide variety of building ages = varied defects
- 1930s properties: cavity wall tie corrosion, metal window failures
- Victorian properties: full range of period property issues
Richmond
- Higher-end properties with complex roof structures
- Flood risk concerns near river
- Listed building challenges requiring specialist repairs
Prevention Strategy: The 5-Year Maintenance Plan
Smart homeowners in West London budget proactively for property maintenance:
Year 1: Essential Services
Budget: £1,500-£3,000
Electrical condition report. Gas safety certificate. Boiler service. Gutter cleaning. Drainage check. Address any red-rated survey issues.
Year 2: Exterior Maintenance
Budget: £2,000-£5,000
Roof repairs identified in survey. External decoration (if needed). Repointing urgent areas. Window repairs. Gutter maintenance.
Year 3: Damp Treatment
Budget: £3,000-£7,000
DPC installation/renewal. Replastering affected walls. Improved ventilation. Drainage improvements. Gutter maintenance.
Year 4: Major Systems
Budget: £4,000-£10,000
Boiler replacement if over 15 years. Heating system upgrades. Major plumbing works. Electrical upgrades. Gutter maintenance.
Year 5: Roof & Windows
Budget: £5,000-£15,000+
Roof replacement if needed. Window restoration/replacement program. External decoration. Structural monitoring follow-up. Gutter maintenance.
Total 5-year budget: £15,500-£40,000 (£3,000-£8,000 per year)
Maintenance Reserve Fund
Set aside 1-2% of property value annually for maintenance. For a £750,000 West London property, that's £7,500-£15,000 per year. This covers routine maintenance plus allows for major projects as needed.
How Surveys Identify These Defects
Professional RICS surveys use various tools and techniques to detect defects:
- Moisture meters - Detect hidden damp in walls and timbers
- Thermal imaging - Reveals insulation gaps, air leaks, hidden moisture
- Borescopes - Inspect hidden cavities and voids
- Spirit levels - Detect sloping floors and walls
- Crack monitoring gauges - Determine if movement is historic or ongoing
- Drainage testing equipment - Check underground drains
- Electrical testing devices - Assess earthing and circuit safety
When to Get Specialist Reports
Your building survey may recommend additional specialist investigations:
| Specialist Report | When Needed | Typical Cost |
|---|---|---|
| Structural Engineer | Serious structural movement, major alterations, complex issues | £800-£2,000 |
| Electrical (EICR) | Properties over 30 years old, visible old wiring | £150-£300 |
| Drainage Survey (CCTV) | Suspected drainage problems, old clay pipes | £200-£400 |
| Timber & Damp Specialist | Evidence of rot, extensive damp, beetle infestation | £200-£500 |
| Asbestos Survey | Properties built 1950-1999, pre-renovation | £250-£500 |
Red Flags That Should Stop a Purchase
Some defects are so serious that proceeding is ill-advised:
- Active, progressive structural movement with repair costs exceeding 15% of property value
- Extensive dry rot affecting multiple floors and requiring £30,000+ remediation
- Illegal structural alterations impossible to certify retrospectively
- Severe subsidence with ongoing tree-related issues and no insurance
- Properties requiring £50,000+ in immediate essential repairs
- Dangerous electrical installations throughout with inadequate earth
- Major undisclosed building regulation breaches affecting saleability
When to Walk Away
If repair costs exceed 20% of the purchase price, or if the seller refuses to negotiate despite serious defects, seriously consider withdrawing. The money lost on surveys and legal fees (typically £1,500-£2,500) is insignificant compared to buying a property with £40,000+ of problems.
Using Defect Information to Negotiate
Survey findings are powerful negotiating tools. Present evidence professionally:
- Obtain contractor quotes for all major defects
- Calculate total repair costs with 10-15% contingency
- Request realistic price reduction (typically 50-70% of repair costs)
- Alternative: request specific repairs completed before exchange
- Consider retention schemes where funds held back pending work completion
Key Takeaways
- 78% of West London properties have at least one defect requiring attention
- Subsidence, damp, and roof issues are the most expensive defects to remedy
- Most defects are manageable if budgeted for and addressed systematically
- Professional surveys using specialist equipment identify hidden problems
- Budget 1-2% of property value annually for ongoing maintenance
- Use survey findings to negotiate price reductions averaging £4,200
- Walk away from properties requiring £50,000+ immediate essential repairs
- Prevention (£100s) is cheaper than cure (£1000s)
Get a Professional Survey from West London Specialists
West London Surveyors has inspected thousands of properties across Hammersmith, Fulham, Ealing, Chiswick, and Richmond. We know exactly what defects to look for in each property type and age, and our comprehensive reports detail every issue with photographic evidence and realistic repair costs.
Our RICS chartered surveyors use thermal imaging, moisture meters, and decades of local experience to identify problems others miss. We've saved our clients hundreds of thousands of pounds by identifying serious defects before purchase, enabling informed negotiations or timely withdrawals.
Don't buy blind - get a comprehensive building survey that reveals the true condition of your prospective West London property.