Builder Costs in Harrow
London | Prices updated for 2026 | All estimates include labour and materials
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Estimated cost in Harrow
£18,340 - £49,780
Single Storey Extension (medium (15-25 sqm))
Typical duration: 6-12 weeks
Builder Prices in Harrow
Single Storey Extension
£18,340 - £49,780Labour
£10,480 - £26,200
Materials
£7,860 - £23,580
Typical duration: 6-12 weeks
Garage Conversion
£8,515 - £19,650Labour
£5,240 - £11,790
Materials
£3,275 - £7,860
Typical duration: 2-4 weeks
Internal Wall Removal
£917 - £3,013Labour
£655 - £1,965
Materials
£262 - £1,048
Typical duration: 1-3 days
Patio Construction
£1,703 - £5,895Labour
£1,048 - £3,275
Materials
£655 - £2,620
Typical duration: 2-5 days
How Harrow Compares
More expensive
Trade prices in Harrow are typically 31% above the national average. This reflects local labour rates and the cost of living in London.
Seasonal Demand for Builder Work
Peak demand is typically in Jul, with the quietest period around Jan. You may find lower prices and better availability during off-peak months.
What Affects the Price
Single Storey Extension
- Extension size (square metres)
- Foundation type required by ground conditions
- Roof design (flat, pitched, or lean-to)
- Level of internal finish and specification
- Planning permission or permitted development status
Garage Conversion
- Garage size and structural condition
- Level of insulation and damp proofing needed
- Whether plumbing or electrics are required
- Quality of internal finish
Internal Wall Removal
- Whether the wall is load-bearing
- Steel beam size and specification
- Services (pipes, wires) running through the wall
- Making good to floor, ceiling, and adjacent walls
Patio Construction
- Patio area (square metres)
- Material choice (concrete slabs, natural stone, porcelain)
- Ground preparation and levelling
- Drainage and edging requirements
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Frequently Asked Questions
How much does a builder cost in Harrow?
Builder prices in Harrow typically range from £917 for internal wall removal to £49,780 for single storey extension. Prices include both labour and materials.
What is the average cost of single storey extension in Harrow?
Single Storey Extension in Harrow costs between £18,340 and £49,780 on average, depending on the scope of work and materials chosen.
When is the cheapest time to hire a builder in Harrow?
Demand for builder work in Harrow is typically lowest in January. Booking during quieter months may mean better availability and competitive pricing.
Are builder prices in Harrow above or below the national average?
Builder prices in Harrow are around 31% above the national average, reflecting higher local labour rates and cost of living.
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