Portsmouth, Hampshire
Double Storey Extension in Portsmouth
A double storey extension adds significant space on two levels, making it cost-effective per square metre compared to two separate single storey extensions.
Estimated Cost
£55,200 – £87,400
Based on 40m² at local rates
12–20 weeks typical duration
Planning permission: Usually required
Cost Breakdown for Double Storey Extension
Estimated costs for a typical 40m² double storey project, adjusted for local labour and material rates.
| Category | Low Estimate | High Estimate |
|---|---|---|
| Foundations & Groundworks | £6,624 | £10,488 |
| Structural Walls | £8,280 | £13,110 |
| Roof Structure & Covering | £5,520 | £8,740 |
| Windows & Doors | £4,416 | £6,992 |
| Plumbing & Drainage | £4,416 | £6,992 |
| Electrical Installation | £3,312 | £5,244 |
| Plastering & Rendering | £3,312 | £5,244 |
| Flooring | £2,760 | £4,370 |
| Kitchen/Bathroom Fitting | £5,520 | £8,740 |
| Decoration & Finishing | £2,760 | £4,370 |
| Professional Fees | £5,520 | £8,740 |
| Contingency (10%) | £2,760 | £4,370 |
| Total Estimated Cost | £55,200 | £87,400 |
* Costs are estimates based on regional averages and may vary depending on specification, access, and site conditions. Prices include VAT at 20%.
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