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Common Property Defects Found During Building Surveys

January 2025 14 min read
Structural crack in property
68%
Properties Have Damp
85%
Have Some Defects
£8,500
Average Repair Cost
Top 10
Most Common Issues

During thousands of building surveys conducted across Milton KeynesGrowing city with diverse property stock from 1970s new towns to Victorian villages, Bedford, Northampton, and Buckinghamshire, our RICS chartered surveyors regularly identify defects that would have gone completely unnoticed by property buyers during viewings. Understanding common property defects helps you appreciate why professional surveys are essential and what to watch for when buying property.

This comprehensive guide from Milton Keynes Surveyors covers the most frequent defects we encounter, their causes, implications, repair costs, and how to negotiate with sellers when problems are identified.

Survey Statistics: 85% of properties surveyed have at least one defect requiring attention. 68% have damp issues. Average repair costs identified: £5,000-£15,000. Don't skip your survey!

Interactive Defect Severity Assessment Tool

Assess Your Property Defect's Severity

Use this tool to understand how serious a defect might be based on symptoms you've observed or survey findings. Answer questions about what you've seen:

1. Damp and Moisture Problems

Damp is consistently the most common defect identified during building surveys throughout the region. Our chartered surveyors use moisture meters, thermal imaging cameras, and visual inspection to detect damp issues that aren't obvious to untrained eyes.

Rising Damp

Rising damp occurs when groundwater rises through masonry due to absent, damaged, or bridged damp-proof courses (DPC). Common in older properties across Milton Keynes and Bedford built before modern DPC standards.

Signs to Look For
  • Tide marks on walls - Horizontal staining up to 1 meter high
  • Salt deposits - White crystalline deposits on wall surfaces
  • Peeling paint and wallpaper - Particularly at skirting level
  • Rotting skirting boards - Timber decay at floor level
  • Damp musty smell - Especially noticeable in ground floor rooms
  • Black mold - On lower portions of walls
Common Causes
  • No DPC: Pre-1875 properties often have no damp proof course
  • Failed DPC: Physical DPCs can deteriorate after 100+ years
  • External ground levels raised above DPC: Paving or soil bridging the barrier
  • Bridging by render: External render extending below DPC
  • Internal floor levels: Concrete floors cast above DPC level
Solutions: Chemical DPC injection (£30-50 per meter), replastering with salt-resistant plaster, lowering external ground levels, removing bridging.
£1,500
Minimum Cost
£4,000
Typical Cost

Penetrating Damp

Water penetrating through walls, roofs, or windows due to defects in the building fabric. More common after heavy rain.

Key Indicator: Penetrating damp is usually worse after rainy weather and in specific locations (unlike rising damp which is consistent at low level).

Signs: Damp patches on walls (often worse after rain), mold growth, water stains, decaying timber, damp penetrating from specific points

Common Causes:

  • Defective roof coverings or flashing - Missing tiles, failed valleys
  • Blocked or damaged gutters and downpipes - Overflowing onto walls
  • Failed pointing or rendering - Allowing rain penetration
  • Cracked or porous brickwork - Particularly on exposed elevations
  • Defective windows or door frames - Failed seals, rotting timber

Solutions: Depends on cause - roof repairs, gutter cleaning/replacement, repointing, render repairs, window replacement

£500
Minor Repairs
£5,000+
Extensive Work

Condensation

The most common form of damp, particularly in modern properties with inadequate ventilation. Often misdiagnosed as rising or penetrating damp.

Signs:

  • Mold on walls and ceilings (especially corners and behind furniture)
  • Water droplets on windows in morning
  • Musty smell throughout property
  • Black mold in bathrooms and kitchens
  • Damp clothing and soft furnishings
Understanding Condensation: Warm, moist air hitting cold surfaces forms water droplets. Common in properties with poor ventilation, inadequate heating, and lifestyle factors (cooking, drying clothes indoors).

Solutions:

  • Improved ventilation - trickle vents, extractor fans
  • Better heating - maintain consistent temperatures
  • Dehumidifiers for problem areas
  • Anti-condensation paint
  • Lifestyle changes - open windows, dry clothes outside

Typical Cost: £500-2,000 for ventilation improvements

Damp and moisture meter

2. Structural Movement and Subsidence

Structural movement is one of the most serious defects identified during surveys. Our RICS surveyors carefully assess cracks to determine whether they indicate historic settled movement or ongoing subsidence.

Subsidence Impact: Active subsidence can make properties unmortgageable, uninsurable, and cost £15,000-£50,000+ to repair. Always investigate suspicious cracks.

Subsidence: Warning Signs

Downward movement of foundations due to soil shrinkage, commonly affecting clay soils prevalent across parts of Milton Keynes, Bedford, and Buckinghamshire.

Warning Signs:

  • Cracks wider than 5mm - Particularly if tapering (wider at top)
  • Diagonal cracks - Around windows and doors, in corners
  • Visible both internally and externally - Through-wall cracking
  • New or expanding cracks - Recently appeared or getting worse
  • Doors and windows sticking - Frames distorted by movement
  • Rippling in wallpaper - Where walls have moved
  • Cracks near extensions - Differential movement
Crack Width Severity Guide
Width Severity Typical Cause Action Required
<1mm Minor Normal settlement, shrinkage Monitor only
1-5mm Moderate Settlement, thermal movement Monitor, possible minor repairs
5-15mm Serious Possible subsidence Structural engineer investigation
>15mm Severe Likely subsidence/heave Urgent structural engineer, possible underpinning

Common Causes of Subsidence

  • Tree roots extracting moisture - Clay soils shrink when dry, particularly problematic with large trees near properties
  • Leaking drains - Water washing away supporting soil beneath foundations
  • Ground heave - Clay soils expanding after trees removed
  • Poor original construction - Inadequate foundations
  • Mining subsidence - Relevant in some areas
  • Soil type changes - Made ground, infilled land

Solutions & Costs

  • Monitoring: £300-500 - Tell-tales or crack monitoring over 12 months
  • Tree management: £500-2,000 - Pruning, pollarding, or removal
  • Drainage repairs: £1,000-5,000 - Fix leaking drains
  • Underpinning: £5,000-15,000 per wall - Mass concrete underpinning
  • Piling: £10,000-30,000+ - For severe cases
Mortgage & Insurance Impact: Active subsidence may make property unmortgageable until repaired. Buildings insurance may be affected. Always disclose subsidence when selling.

Settlement vs Subsidence

Settlement is normal - New buildings settle as they adjust to loading. Historic settlement in older properties is common and not usually problematic if movement has ceased.

Subsidence is ongoing movement requiring investigation and potential treatment. Our chartered surveyors assess crack patterns, monitor existing cracks for progression, and recommend whether specialist structural engineer investigation is warranted.

How We Assess: Surveyors look at crack width, pattern, location, whether visible inside and outside, age of property, soil type, nearby trees, and evidence of recent movement to determine severity.

3. Roof Defects

Roof problems are among the most expensive defects to remedy, commonly identified during building surveys across the region.

Tile and Slate Issues

Common problems:

  • Slipped, cracked, or missing tiles/slates
  • Deteriorating nail fixings (tiles sliding)
  • Delaminating slates (splitting into layers)
  • Ridge tiles loose or missing
  • Aging roofing felt visible in roof space
  • Inadequate roof insulation
£50-100
Per Tile/Slate
£3k-8k
General Overhaul
£5k-15k+
Full Re-roof

Flat Roof Deterioration

Felt flat roofs typically last 15-25 years. Many properties across Milton Keynes have aging flat roofs approaching or exceeding their life expectancy.

Signs of Failure:

  • Blistering of felt surface
  • Cracking and splitting
  • Ponding water (inadequate falls)
  • Felt separating from substrate
  • Internal water stains/leaks
  • Moss and vegetation growth
Modern Solutions: Flat roof replacement using modern materials like EPDM rubber, GRP (fiberglass), or high-performance felt provides 20-30 year lifespan.

Typical Costs: £800-1,500 per 10m² depending on material and access

Flashing Defects

Lead flashing around chimneys, valleys, and abutments deteriorates or was poorly installed originally.

Problem Areas:

  • Chimney flashing cracked or pulled away
  • Valley lead split or holed
  • Abutment flashings failed
  • Apron flashings around dormers

Solutions: Flashing repair/replacement: £300-1,000 depending on extent and accessibility

Surveyor inspecting roof

4. Timber Defects

Timber problems affect roof timbers, floor joists, and structural elements throughout properties across Milton Keynes and surrounding areas.

Woodworm (Furniture Beetle)

Small exit holes (1-2mm) in timber indicate historic or active woodworm infestation.

Assessment: Fresh boring dust (frass) indicates active infestation requiring treatment. Old, inactive infestation is common in roof timbers and not problematic if timber remains structurally sound.

How to Tell if Active: Fresh, light-colored boring dust below holes = active. Old holes with no dust = historic infestation that's ceased.

Treatment: Chemical treatment £500-2,000 depending on extent. Severely affected structural timber requires replacement.

Wet Rot

Fungal decay of damp timber, common where timber has been persistently wet (moisture content >20%).

Common Locations:

  • Window frames and cills
  • External door frames
  • Embedded wall plates in damp walls
  • Roof timbers near leaks
  • Floor joists in damp subfloors

Identification: Darkened timber, cracking along grain, soft spongy texture, fungal growth

Solutions: Remove and replace affected timber, address source of moisture

Cost: Window replacement £300-800 each, structural timber repairs £1,000-5,000+

Dry Rot (Serpula Lacrymans)

More serious fungal decay that can spread through masonry to attack dry timber. Less common but more dangerous than wet rot.

Highly Destructive: Dry rot can spread rapidly through properties, attacking structural timber. Requires specialist treatment including sterilization of masonry.

Signs:

  • Mushroom-like fruiting bodies (pancake shaped, orange/brown)
  • Cuboidal cracking in timber (shrinks and cracks in cube pattern)
  • Fine white mycelium strands (cotton wool-like)
  • Damp musty smell
  • Timber crumbles when probed

Treatment: Specialist dry rot treatment £2,000-10,000+ including timber replacement, sterilization of masonry, replastering, and addressing moisture source

5. Electrical Installation Issues

Outdated or defective electrical installations are common in older properties throughout the Milton Keynes area.

Safety Critical: Electrical defects cause thousands of house fires annually in the UK. Outdated wiring is a serious safety risk requiring professional attention.

Common Issues Identified

  • Old rubber or fabric insulated wiring - Pre-1950s, seriously unsafe
  • Aluminum wiring - 1960s-1970s, fire risk, needs replacement
  • Inadequate earthing - Risk of electric shock
  • Missing RCD protection - No protection against electrocution
  • Overloaded circuits - Dangerous heat buildup
  • DIY alterations - Non-compliant, unsafe work
  • Old fuse boxes - Should be modern consumer units
  • No electrical certificate - Installation over 25 years old

Our Recommendations

Our surveyors recommend electrical testing (EICR - Electrical Installation Condition Report) for:

  • Installations over 25 years old
  • Properties with visible concerns
  • No recent electrical certificate available
  • Evidence of DIY work
  • Old wiring systems

EICR Cost: £150-300 from registered electrician (NICEIC, NAPIT, or ECA)

£500-1k
Consumer Unit Upgrade
£3k-6k
Full Rewire (Average House)

Other Common Defects

6. Drainage Problems

Drainage defects affect many properties but aren't always obvious during surveys as drains are underground.

Warning Signs: Cracked/broken inspection covers, slow draining, foul smells, damp patches near drains, rodent problems

Investigation: CCTV drainage survey £150-400

Solutions: Drain repairs £500-2,000, major drainage works £5,000-15,000+

7. Window and Door Issues

Common Problems: Rotting timber frames, failed putty, failed double-glazing units (condensation between panes), poorly fitted replacements, missing/damaged glazing

Solutions: Window repairs £100-300 each, full replacement £300-800 per window

8. Chimney and Flue Defects

Issues: Leaning/unsafe stacks, deteriorating pointing, missing chimney pots, unsupported removed breasts, uncapped chimneys

Solutions: Repointing £500-1,500, stack rebuilding £1,500-4,000, chimney capping £200-500

9. Pointing and Masonry Issues

Deteriorating pointing (mortar between bricks) is common in properties over 50 years old.

Problems: Eroded pointing allowing water penetration, incorrect hard cement pointing causing brick damage (should be lime mortar in older properties), cracked or spalling bricks

Solutions: Repointing £40-60 per m², full house £2,000-6,000

10. Heating System Defects

Common Issues: Boilers over 15 years old approaching end of life, old inefficient systems, corroded radiators/pipework, lack of controls/thermostats, unserviced systems

Solutions: New combi boiler £1,500-3,000, system upgrade £3,000-6,000

How Survey Reports Present Defects

Understanding survey condition ratings helps you prioritize defects identified:

RICS Level 2 Survey Traffic Light System

Rating Meaning Urgency Examples
Condition 1
(Green)
No repair currently needed Normal maintenance only Property in good condition, routine upkeep required
Condition 2
(Amber)
Defects needing repair or replacement Not urgent but plan repairs Aging roof, deteriorating pointing, window repairs needed
Condition 3
(Red)
Serious defects requiring urgent attention Immediate action needed Active subsidence, serious damp, electrical hazards, structural issues
Level 3 Building Surveys provide even more detail with comprehensive technical descriptions of all defects, extensive photographs throughout, repair cost estimates, and detailed maintenance guidance.

What To Do When Defects Are Identified

When your survey identifies defects, you have several options. Choose based on the severity and your circumstances:

Option 1: Proceed As Planned

When appropriate: If defects are minor, you're comfortable addressing them after purchase, and total repair costs are manageable.

Benefits:

  • Purchase proceeds smoothly without delays
  • You maintain good relationship with seller
  • You can manage repairs on your own timeline
  • You know exactly what needs doing (from survey)

Best for: Properties with only Condition 2 (amber) defects, routine maintenance issues, or minor problems you can afford to fix.

Option 2: Renegotiate Price

When appropriate: Significant defects identified that will cost substantial amounts to repair.

How to renegotiate:

  1. Get repair quotes from contractors
  2. Calculate total repair costs
  3. Request price reduction (typically 50-80% of repair costs)
  4. Present survey findings and quotes professionally
  5. Be prepared to negotiate/compromise
Negotiation Tips: Be reasonable - don't try to renegotiate based on routine maintenance. Focus on significant Condition 2 and all Condition 3 items. Most sellers expect some negotiation after surveys.

Option 3: Request Repairs

When appropriate: Urgent issues, safety concerns, or problems affecting mortgage availability.

Best for:

  • Electrical safety issues
  • Urgent roof leaks
  • Defects affecting mortgage approval
  • Work better done while property empty
Important: Request written confirmation of completed work, contractor invoices, and any guarantees. Consider having your surveyor re-inspect before completion to verify work quality.

Option 4: Walk Away

When appropriate: Serious structural problems, prohibitive repair costs, or defects making property unsuitable.

Walk away if you discover:

  • Active subsidence requiring £15,000-£50,000+ underpinning
  • Widespread structural issues affecting safety/habitability
  • Japanese knotweed (mortgage-blocking, very expensive treatment)
  • Major defects making property unmortgageable
  • Total repair costs exceeding your budget by £20,000+
  • Serious undisclosed issues suggesting seller dishonesty
Remember: This is WHY you get a survey - to identify deal-breaker issues before you're legally committed. Better to lose survey costs (£400-£700) and legal fees (£500-£1,000) than be stuck with a property requiring tens of thousands in repairs.

Conclusion: Knowledge is Protection

Understanding common property defects helps you appreciate why professional RICS building surveys are essential when buying property in Milton Keynes, Bedford, Northampton, and surrounding areas. The defects discussed in this guide are regularly identified by our chartered surveyors, often in properties that looked perfect during viewings.

A professional survey provides detailed information about your property's condition, helping you:

  • Make informed decisions based on facts, not assumptions
  • Negotiate fairly with sellers when defects are found
  • Budget realistically for repairs and maintenance
  • Avoid financial disasters from hidden problems
  • Plan future work with clear priorities
1000s
Surveys Completed
£5k-15k
Average Issues Found
100%
Professional Protection

Milton Keynes Surveyors' RICS chartered surveyors provide comprehensive Level 2 and Level 3 building surveys across the region, identifying defects and providing clear guidance on their implications, urgency, and estimated repair costs.

Don't risk buying a property with hidden defects. Contact Milton Keynes Surveyors today for expert surveying services throughout Milton Keynes, Bedford, Northampton, Luton, and Buckinghamshire.

Need a Building Survey?

Our RICS chartered surveyors identify property defects across Milton Keynes and the surrounding area, providing detailed reports that help you make informed decisions.

What we identify:

  • All types of damp and moisture problems
  • Structural movement and subsidence
  • Roof defects and deterioration
  • Timber problems (woodworm, rot)
  • Electrical installation issues
  • Drainage problems
  • And much more...
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