Not all building work pays for itself. Some projects add significantly more value than they cost; others barely break even. This guide shows the real value uplift for common projects, by London zone and UK region, based on Land Registry and market data.
Value Impact by Project Type
| Project | Typical Cost (Standard) | Value Added (London) | Value Added (UK avg) |
|---|---|---|---|
| Loft conversion (dormer) | £45,000–£60,000 | +£75,000–£100,000 | +£30,000–£45,000 |
| Rear extension (single storey) | £55,000–£75,000 | +£85,000–£115,000 | +£35,000–£50,000 |
| Kitchen renovation | £25,000–£35,000 | +£20,000–£30,000 | +£10,000–£18,000 |
| Bathroom renovation | £12,000–£18,000 | +£8,000–£12,000 | +£5,000–£8,000 |
| Heat pump installation | £10,000–£16,000 | +£5,000–£10,000 (EPC uplift) | +£3,000–£6,000 |
Why London Sees Bigger Returns
Higher base property values mean the same percentage uplift translates to a larger absolute number. A loft conversion adding 10% to a £1.2m London property adds more in cash terms than the same 10% on a £280,000 UK-average home.
Get a Value Impact Estimate for Your Project
These are typical ranges. For your specific postcode and project, use the free calculator on our Home page.
Disclaimer:
All figures are indicative estimates only, based on general market data. Actual property value impact depends on local market conditions, comparable sales, structural survey results, and finish quality. FairBuildCost.co.uk does not provide property valuations.