Total Estimated Cost: £0
Excavation: £0
Foundations: £0
Drainage: £0
Materials & Labour: £0
Contingency (10%): £0
Per m²: £0 (based on 2025 UK rates)
How to Use
Enter project details like area and depth, select options for soil and access, then click the button for instant breakdown. Adjust values live for updates. Figures include VAT-exclusive labour, materials and plant hire.
Cost Principles
Estimates factor excavation volume (area x depth x £100/m³ average), foundation rates by type, drainage at £75/m linear, plus 40% for labour/plant and regional multipliers. Soil adjusts difficulty: rock needs blasting. Access adds transport fees. Contingency covers surprises like wet ground.
Frequently Asked Questions
What does this cover? Site clearance, digging, concrete pours, pipes and backfill for typical builds.
Are VAT and permits included? Core costs exclude VAT (add 20%) and planning fees (£200-£500).
How accurate for my site? Within 15-20% of quotes; get pro survey for ground probes.
Why higher in London? Labour £4500-£6500/project average, plus material delivery premiums.
UK Regional Comparisons
| Region | Avg per m² | 3-Bed House Example |
|---|---|---|
| London | £250-£350 | £35,000-£50,000 |
| Midlands | £200-£280 | £28,000-£40,000 |
| South West | £210-£290 | £29,000-£41,000 |
| North/Wales | £180-£260 | £25,000-£36,000 |
Foundation Type Comparisons
| Type | Cost per Unit | Best For |
|---|---|---|
| Strip | £100-£200/m³ | Light loads, good soil |
| Trench | £150-£400/m | Deeper support |
| Raft | £250-£350/m³ | Poor soil, even spread |
| Pad | £200-£350/pad | Columns/frames |
Common Pitfalls
- Overlooking soil tests: Clay swells; add £5,000 for stabilisation on 100m².
- Ignoring access: Remote sites double haulage to £10/m³ from £5.
- Fixed quotes early: Ground reveals boulders; budget 10-20% extra.
- Skipping drainage: Flood risk adds £15,000 rectification later.
- Regional mismatch: Use local rates; London 20% over national.
References
- RICS. (2018). Cost analysis and benchmarking (2nd ed.). Royal Institution of Chartered Surveyors.
- Build Partner. (2025). Average building costs per sq m for 2025 – A UK guide. https://buildpartner.com/average-building-costs-per-sq-m-for-2025-a-uk-guide/
- A&M Groundworks. (2025). How much does groundwork cost? https://aandmgroundworks.co.uk/blog/how-much-does-groundwork-cost
- MyBuilder. (2024). Foundation digging cost guide. https://www.mybuilder.com/groundwork-foundations/price-guides/foundation-digging-cost
- Dart & Co. (2023). Foundations cost calculator. https://dartandco.co.uk/foundations-cost-calculator/