Extension Cost Per Square Metre 2026: What to Expect in Weymouth
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 Weymouth homeowners should expect to pay.
Local cost range — Weymouth
£1,700–£2,500/m²
What affects costs in Weymouth
Weymouth build rates are slightly below the Dorset average, making it an affordable area to extend. Seafront properties are the exception due to marine exposure requirements.
Cost estimator
Rates for Weymouth
6m × 4m = 24m²
Estimated cost in Weymouth
Excl. VAT (£9821 – £14720)
Local insight: Weymouth offers some of the most affordable build rates in the area. Seafront properties are the exception — salt air exposure requires marine-grade materials.
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 Weymouth: £1,700–£2,500/m².
Frequently asked questions
National guide
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