Chelmsford, Essex
Double Storey Extension in Chelmsford
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
£56,640 – £89,680
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 | £6,797 | £10,762 |
| Structural Walls | £8,496 | £13,452 |
| Roof Structure & Covering | £5,664 | £8,968 |
| Windows & Doors | £4,531 | £7,174 |
| Plumbing & Drainage | £4,531 | £7,174 |
| Electrical Installation | £3,398 | £5,381 |
| Plastering & Rendering | £3,398 | £5,381 |
| Flooring | £2,832 | £4,484 |
| Kitchen/Bathroom Fitting | £5,664 | £8,968 |
| Decoration & Finishing | £2,832 | £4,484 |
| Professional Fees | £5,664 | £8,968 |
| Contingency (10%) | £2,832 | £4,484 |
| Total Estimated Cost | £56,640 | £89,680 |
* 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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