Loft Conversion Cost: Complete Breakdown 2026 in Ferndown
A loft conversion is one of the best-value home improvements — it adds a bedroom and bathroom without losing garden space. Costs range from £30,000 for a simple Velux conversion to £90,000 for a full mansard, depending on the type and specification. Here is what Ferndown homeowners should expect to pay.
Local cost range — Ferndown
£40,000–£70,000
What affects costs in Ferndown
Ferndown's bungalows are particularly suited to dormer and hip-to-gable conversions, effectively adding a full upper floor at a fraction of the cost of building upwards.
Cost estimator
Rates for Ferndown
6m × 4m = 24m²
Estimated cost in Ferndown
Excl. VAT (£9821 – £14168)
Local insight: Ferndown's generous plot sizes and good access make it one of the most straightforward (and cost-effective) areas to extend in Dorset. Bungalow conversions are particularly popular here.
Cost breakdown
Cost by conversion type
Velux/rooflight: £30,000–£45,000 (simplest, no structural roof changes). Rear dormer: £40,000–£60,000 (most popular, adds headroom). L-shaped dormer: £50,000–£70,000 (two dormers meeting at a corner). Hip-to-gable + dormer: £55,000–£75,000 (maximises space on hipped roofs). Mansard: £65,000–£90,000 (most complex, most space).
What drives the cost
The main cost factors are: (1) type of conversion (dormer/mansard cost more than Velux); (2) size (one room or two); (3) en-suite bathroom (adds £5,000–£10,000); (4) staircase complexity (over the existing stair is cheapest); (5) access difficulty (scaffolding costs vary).
Professional fees for loft conversions
Design starts with the Layout Ideas Pack, done remotely or in person (subject to coverage). Structural calculations (always needed for floor joists and any roof steels), the planning application, and Building Regulations drawings are priced after that. The council also charges a planning application fee if one is required, set nationally and revised each year — the Planning Portal lists the current fees. Building control fees are separate.
| Type | Build Cost | Estimated Total |
|---|---|---|
| Velux/rooflight | £30,000–£45,000 | £35,000–£55,000 |
| Rear dormer | £40,000–£60,000 | £48,000–£72,000 |
| L-shaped dormer | £50,000–£70,000 | £58,000–£82,000 |
| Hip-to-gable + dormer | £55,000–£75,000 | £63,000–£88,000 |
| Mansard | £65,000–£90,000 | £75,000–£105,000 |
National guide figures. Local rates in Ferndown: £40,000–£70,000.
Frequently asked questions
National guide
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