Properties built before 2000 likely contain asbestos. Survey costs £250-500, removal £1,500-8,000 depending on type. Artex ceilings, floor tiles, cement roofs most common. HSE licensed contractor required.
Risk Properties: Built or extended before 2000 (asbestos banned 1999)
Survey Cost: £250-500 for typical 2-3 bed house (refurbishment survey)
Removal Cost: £1,500-3,500 typical, up to £8,000 for extensive work
Most Common: Artex ceilings (pre-1985 highest risk), floor tiles, cement roofing
Legal Requirement: HSE licensed contractor for most removals (Control of Asbestos Regulations 2012)
Timeline Impact: +1-2 weeks for survey and removal before extension work starts
If your London property was built or extended before 2000, there's a high probability it contains asbestos-containing materials (ACMs). When you build an extension, you'll be disturbing walls, removing roofs, potentially knocking through internal walls - all activities that can release dangerous asbestos fibres if ACMs are present.
According to Oracle Asbestos industry data, any building constructed or modified before 2000 may contain asbestos. In London, with extensive Victorian, Edwardian, and mid-20th century housing stock, this affects the majority of properties.
Building Control and your builder's insurance will require an asbestos survey for pre-2000 properties. But more importantly:
Asbestos was extensively used in UK construction from the 1950s to 1999 ban. These are the materials you're most likely to encounter when extending a London property:
Where Found: Ceilings and walls throughout house, especially bedrooms and living rooms
Risk Period: Pre-1985 Artex almost always contains asbestos. 1985-1999 lower risk but test required
Removal Cost: £800-1,500 per ceiling (scraping + disposal)
Extension Impact: If knocking through to create open-plan, need to remove Artex from existing rooms to access ceiling joists
Where Found: Garage roofs, outbuilding roofs, occasionally existing rear extensions
Risk Period: Pre-2000 cement roofing sheets
Removal Cost: £50-80/m² (higher than other UK regions due to London disposal fees)
Extension Impact: Must remove existing garage/outbuilding roof before building over or adjacent to structure
Where Found: Kitchen, bathroom, hallway floors in properties extended pre-2000
Risk Period: 1950s-1980s vinyl floor tiles frequently contained asbestos
Removal Cost: £35-50/m² (lower risk than Artex but requires careful removal)
Extension Impact: Must remove existing floor if extending kitchen, affects floor level transitions
Where Found: Behind fires, in meter cupboards, soffit boards, loft hatches
Risk Period: 1960s-1980s high-rise and local authority housing
Removal Cost: £1,000-2,500 (high risk material, requires licensed removal)
Extension Impact: If knocking through walls, may discover AIB panels behind existing structure
Where Found: Around hot water pipes, boiler cupboards, especially older heating systems
Risk Period: Pre-1970s very common, declining 1970s-1999
Removal Cost: £500-1,500 depending on extent
Extension Impact: Heating system often relocated/upgraded during extension, triggers removal
According to Checkatrade's 2025 cost guide, there are two types of asbestos surveys. For extensions, you need the second type.
| Survey Type | Purpose | Cost (2-3 Bed House) | For Extensions? |
|---|---|---|---|
| Management Survey | Identifies presence of asbestos in occupied buildings for management | £150-350 | ❌ Not sufficient |
| Refurbishment & Demolition Survey | Intrusive survey before major works, identifies all ACMs in work area | £300-500 | ✅ Required |
Timeline: Book survey 2-3 weeks in advance (demand high in London). Allow 1-2 weeks from survey visit to receiving report.
According to Oracle Asbestos removal cost data, London costs run 15-25% higher than UK average due to:
| Material Type | Typical Quantity | London Cost | License Required |
|---|---|---|---|
| Artex ceiling (one room) | 12-15m² | £800-1,200 | ✅ Yes |
| Artex whole ground floor | 40-50m² | £2,500-3,500 | ✅ Yes |
| AC roof sheets (garage) | 20-25m² | £1,200-1,800 | ❌ No (if intact) |
| Floor tiles (kitchen) | 15-20m² | £600-1,000 | ❌ No |
| AIB panels (behind walls) | 5-8m² | £1,500-2,500 | ✅ Yes |
| Pipe lagging | 10-15m run | £800-1,500 | ✅ Yes |
Asbestos disposal in UK costs £0.55-0.80 per kilogram. For typical extension asbestos removal:
According to Control of Asbestos Regulations 2012, some asbestos work requires HSE licensed contractors, some doesn't.
Verify License: Check HSE website for valid license number. Licensed contractors hold BOHS P402 qualification minimum.
Important: "Competent person" means someone with asbestos awareness training, not just any builder. Most builders subcontract all asbestos work to avoid liability.
When: Before architect finalizes designs
Why: May affect design (e.g., can't knock through walls with AIB without expensive removal)
Cost: £300-500
Timeline: 1-2 weeks from survey visit
Action: Get removal quotes if ACMs found (2-3 contractors)
Budget: Add £2,000-8,000 to extension cost (typical range)
Timeline: Add 1-2 weeks for asbestos removal before builder starts
Include removal cost in funding/loan applications
Timeline: 3-5 days typical removal + 2-3 days for air testing clearance
You Must: Vacate property during licensed removal work
After: Contractor provides waste consignment notes + air test certificate
Requirement: Builder needs copy of asbestos survey + removal certificates
Building Control will ask for these documents at first inspection
According to Tradesmen Costs analysis, encapsulation (sealing asbestos in place) can be cheaper alternative at £8/m², but rarely suitable for extensions.
| Factor | Encapsulation | Removal |
|---|---|---|
| Cost | £8/m² (much cheaper) | £35-225/m² depending on type |
| When Suitable | Asbestos not being disturbed Material in good condition Not in work area | Any situation Permanent solution Required when material disturbed |
| For Extensions? | ❌ Rarely appropriate (work disturbs ACMs) | ✅ Standard approach |
| Future Issues | Asbestos still present Must declare when selling Future work requires removal | Problem permanently eliminated No disclosure required No future issues |
Extension Verdict: Encapsulation only works if ACM is far from extension work area and won't be disturbed. For example, Artex in first floor bedrooms when building single-storey rear extension. Even then, removal is cleaner long-term solution.
Get 2-3 quotes from licensed contractors. Provide asbestos survey report for accurate pricing. Ask for:
While technically legal for homeowners to remove some asbestos types from their own property, it's dangerous and impractical for extension projects:
Verdict: The £1,500-3,500 professional cost is money well spent for safety and compliance.
You can't tell by looking. Any building built or extended before 2000 may contain asbestos. Properties from 1950s-1980s have highest probability. The only way to confirm is through a refurbishment & demolition survey by a qualified surveyor (£300-500). Don't rely on previous owners saying "no asbestos" - they may not know about hidden ACMs.
No. Control of Asbestos Regulations 2012 require duty-holders (you as homeowner) to identify asbestos before any refurbishment work. Building Control will ask for survey evidence. Your builder's insurance requires it. More importantly, you're legally responsible for protecting workers from asbestos exposure - failing to survey before work is a criminal offence with fines up to £20,000.
Work must stop immediately. Seal the area and evacuate. Call HSE incident line (0300 790 6787) if workers may have been exposed. Commission emergency asbestos survey (£500-800 for fast-track). Have material removed by licensed contractor. Work can only resume after air clearance testing. This scenario adds £3,000-5,000 to costs and 2-3 weeks to timeline - why pre-work surveys are cheaper and faster.
Structural warranty providers (NHBC, Premier Guarantee, etc) require evidence of proper asbestos management. You'll need to provide: (1) refurbishment survey report showing no asbestos found, or (2) licensed removal certificates + air test clearance if asbestos was present. Failing to declare known asbestos could void your warranty. Insurance premiums aren't affected if properly removed.
Depends on scope of work. Small-scale non-licensed work (like removing intact garage roof): you can stay if work area sealed off. Licensed removal (Artex, AIB, etc): best practice is to vacate for 3-5 days. Licensed contractors must create sealed enclosure with negative air pressure. While theoretically safe to remain, most London families choose to stay with relatives during work. Contractors prefer unoccupied properties (easier access, no contamination concerns).
No - removal increases value. Properties with asbestos must be declared when selling (Material Information under Consumer Protection Regulations 2008). Undisclosed asbestos can lead to sale fall-through or legal claims. Once properly removed with certificates, you can honestly state "no asbestos present" on property forms. Buyers see proper removal as a positive (one less concern). The £2-8k removal cost is far less than losing a buyer over asbestos fears.
Risk Level: Pre-2000 London properties have 70-80% chance of containing some asbestos materials. Victorian/Edwardian terraces with multiple past extensions highest risk.
Survey Cost: £300-500 for refurbishment & demolition survey (required before extension work). Book 2-3 weeks ahead, allow 1-2 weeks for report.
Removal Cost: £1,500-3,500 typical for common scenarios (Artex ceiling + floor tiles). Up to £8,000 for extensive work. London costs 15-25% higher than UK average.
Timeline Impact: Add 1-2 weeks before builder starts main work. Extension timeline delay is unavoidable but manageable with planning.
Bottom Line: Asbestos is an unwelcome budget addition (£2-8k including survey and removal), but it's non-negotiable for legal and safety reasons. Factor it into your extension budget from the start. The good news: once properly removed, it's permanently solved and actually increases property value by removing a major buyer concern.
The real costs builders don't quote. Party wall £1-3k, asbestos £2-8k, drainage £3-15k, CIL charges. Add 15-25% to builder quotes.
Complete guide to building regs for extensions. Structural, fire safety, insulation, ventilation requirements. Costs and inspection stages.
Complete extension timeline from design to completion. 6-12 months typical. Planning, building regs, party wall, construction stages.