Extension Cost Per Square Metre 2026: What to Expect in New Forest
Cost per square metre is the standard way to compare extension quotes. But the figure varies dramatically depending on specification, region, complexity, and what is included. Here is what New Forest homeowners should expect to pay.
Local cost range — New Forest
£2,000–£3,000/m²
What affects costs in New Forest
New Forest rates are among the highest in the area due to premium material requirements in the National Park and limited local builder capacity.
Cost estimator
Rates for New Forest
6m × 4m = 24m²
Estimated cost in New Forest
Excl. VAT (£11477 – £17480)
Local insight: New Forest properties — especially those inside the National Park — require premium natural materials to comply with NFNPA design guidelines. Expect 10–20% higher build costs than the Dorset average.
Cost breakdown
2026 rates by specification
Basic specification (standard bricks, flat roof, basic windows): £1,500–£2,000/m². Standard specification (quality bricks, bi-fold doors, underfloor heating): £2,000–£2,800/m². Premium specification (bespoke materials, structural glazing, high-end finishes): £2,800–£3,500/m². These are Dorset rates.
What affects the rate
Foundation depth (clay soil or trees nearby = deeper = more expensive), access difficulty (narrow lanes or terraced properties), specification level, bathroom inclusion (wet rooms cost more per m²), and the builder's current availability. A busy builder quotes higher.
| Region | Standard | High Spec |
|---|---|---|
| Dorset | £1,800–£2,200 | £2,500–£3,200 |
| London | £2,500–£3,500 | £3,500–£5,000 |
| South East | £2,000–£2,800 | £2,800–£3,800 |
| Midlands | £1,600–£2,200 | £2,200–£3,000 |
| North | £1,400–£2,000 | £2,000–£2,800 |
National guide figures. Local rates in New Forest: £2,000–£3,000/m².
Frequently asked questions
National guide
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Useful links for New Forest homeowners
External resources we recommend. Links open in a new tab.
Local Authority
- New Forest District Council PlanningNFDC planning guidance and application forms
- New Forest National Park Authority PlanningNFNPA planning portal — separate from district council
- NFDC Conservation AreasMaps and appraisals for district conservation areas
- Check long-term flood riskEnvironment Agency service — enter your postcode