Extension Builder Cost in Greenwich

Extension building is a significant investment for Greenwich homeowners, with costs varying dramatically based on project scope, materials, and local labour rates. Greater London extension costs typically run 25–35% above the national average due to high demand, skilled tradespeople, and stricter building regulations. Whether you're planning a single-storey rear extension, two-storey addition, or full kitchen extension, understanding the factors driving price is essential. BizHub365 connects Greenwich homeowners with vetted local extension builders who provide transparent quotes and reliable project management.

Extension Builder Prices in Greenwich

Service	Typical Cost	Unit
Single-storey rear extension (3×4m)	£8500 – £15000	per project
Two-storey rear extension (4×5m)	£22000 – £38000	per project
Kitchen extension with utilities	£15000 – £28000	per project
Loft conversion (basic)	£18000 – £32000	per project
Extension structural design & planning	£800 – £2500	per project
Brickwork & masonry labour	£150 – £220	per day
Roofing (tiling & membranes)	£85 – £140	per m²
Installation of windows & doors	£300 – £600	per unit fitted

Prices are indicative averages for Greenwich. Actual quotes will vary based on job specifics.

What Affects the Cost?

Extension costs in Greenwich are shaped by several critical factors: ground conditions and site accessibility (Greenwich's mixed geology requires appropriate foundations), local authority planning approval timescales, and compliance with Building Regulations. Material choices—from standard cavity brick to premium finishes—significantly impact budgets. Labour rates in Greater London are substantially higher than the national average. Project complexity, structural requirements (Party Wall Act considerations), and whether utilities (plumbing, electrics) need extending also influence pricing. Seasonal demand and contractor availability in this competitive London market further affect costs.

Money-Saving Tips

Obtain 3–4 detailed quotes from local Greenwich builders to compare pricing transparently. Consider phasing your extension project or choosing standard finishes over premium options. Bundle extensions with loft conversions for contractor efficiency discounts. Plan extensions outside peak summer season (May–August) when demand and labour costs peak in Greater London.

Frequently Asked Questions

What's the typical cost per square metre for an extension in Greenwich?

Single-storey extensions in Greenwich typically cost £1,400–£2,200 per m², whilst two-storey additions range from £2,800–£4,500 per m². These rates include structural work, materials, and labour, but exclude professional fees, planning costs, and contingencies. Prices vary with finish quality and site complexity.

Do I need planning permission for a rear extension in Greenwich?

Most single-storey rear extensions up to 3m depth (or 4m for detached homes) qualify for Permitted Development and don't require full planning permission. However, Greenwich Council planning pre-approval checks are recommended. Two-storey extensions and larger projects require formal planning consent, adding 8–12 weeks and £200–£500 to timescales and costs.

What's included in extension builder quotes for Greenwich?

Standard quotes typically cover demolition, foundations, structural frame, walls, roofing, windows, and basic finishes. They usually exclude: professional design fees (£800–£2,500), planning/Building Control approval costs (£300–£800), utilities relocation, and contingency reserves (10–15% of budget). Always clarify inclusions and ask about Party Wall Act costs if applicable.

How long does an extension project take in Greenwich?

Single-storey extensions typically take 12–16 weeks from start to finish, including planning approval (if required) and Building Control inspections. Two-storey projects run 18–24 weeks. Delays can occur due to site conditions, weather, or building control issues. Your Greenwich builder should provide a detailed timeline at quotation stage.

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