A loft conversion turns unused roof space into a habitable room such as a bedroom, bathroom or office, with a proper staircase, insulation, fire protection and natural light from rooflights or a dormer.
Whether you live in one of the larger towns, such as Swindon, Salisbury, Trowbridge and Chippenham, or somewhere quieter in Wiltshire, the way we handle a loft conversion is identical. We survey, agree the specification with you, and confirm a fixed price on paper. Everything is planned under the regulations in force in England, and guide costs in the South West sit at £30,500–£66,000 with VAT.
- Guide price
- £30,500–£66,000 inc VAT
- Time on site
- 6–10 weeks on site
- Planning rules
- England
- Price level
- About 2% above the national guide
- Towns listed
- 5
- Survey
- Free, with a written quote
Loft conversions prices in Wiltshire
Use the table to gauge the cost of a loft conversion in Wiltshire before we visit. Figures include VAT and are scaled for the South West, coming out about 2% above the national guide, which gives £30,500–£66,000 overall. After a free survey, you receive a fixed written price.
| Type of job | What it usually involves | Guide in Wiltshire |
|---|---|---|
| Rooflight conversion | Rooflights in the existing slope, a new floor, staircase and insulation, where head height already works. | £20,500–£35,500 |
| Dormer conversion | A rear dormer adding headroom and floor space, often with a bedroom and shower room. | £32,500–£61,000 |
| Hip-to-gable or mansard | Larger structural changes to the roof for the maximum usable space. | £51,000–£87,000 |
The main things that change the figure:
- Conversion type: rooflight, dormer, hip-to-gable or mansard
- Steelwork and any strengthening of walls below
- Adding a shower room or en-suite in the roof
- Staircase layout, fire doors and the level of finishes
What do you get?
- Structural calculations and steel beams where needed
- New floor joists strong enough for a habitable room
- Dormer, hip-to-gable or rooflight structure as agreed
- Fire doors, mains-linked smoke alarms and a protected escape route
- Electrics, heating and plumbing by qualified trades, with certificates
- Plastering, internal doors and building control sign-off
Homes in Wiltshire
Salisbury has medieval and Georgian streets, the north-west around Corsham and Bradford on Avon uses Bath stone, and chalk and flint appear on the downland. Swindon has railway-village terraces and very large post-war and modern estates, and many Wiltshire villages have thatched cottages, some with chalk cob walls.
Cob and Bath stone walls need breathable, lime-based repairs, and thatched cottages may need careful roof work. Swindon's railway terraces suit loft rooms and rear extensions, while its large estates often add garage conversions, driveways and landscaping.
Salisbury Plain and the downs are exposed to wind and frost, while river valleys around Salisbury and the Avon can flood.
Planning and building rules in Wiltshire
Homes in Wiltshire come under the regulations for England, summarised below. We don't rely on general rules alone: we confirm the position for your address with the council before a quote goes out.
In England, many loft conversions are permitted development: up to 40 m³ of extra roof space on a terraced house and 50 m³ on a semi-detached or detached house, no dormer on the front roof slope facing a road, nothing higher than the existing roof, and similar-looking materials. Conservation areas, listed buildings and flats need planning permission.
Building Regulations approval is always needed for a loft conversion: floor strength, a proper staircase, insulation, fire-protected escape route and smoke alarms. The Party Wall etc. Act 1996 usually applies on attached houses.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
We look at the job
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Quote in writing
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Booking the work
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Build and hand over
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
What you can expect from us
Questions about a loft conversion in Wiltshire
How much will a loft conversion cost in Wiltshire?
As a guide, expect to pay £30,500–£66,000 including VAT for a loft conversion in Wiltshire. That range is adjusted for the South West, which runs about 2% above the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Can we stay at home during a loft conversion?
Most people stay at home during a loft conversion, because much of the work happens from scaffolding outside and the roof is opened up from above. The most disruptive point is near the end, when we break through the ceiling to fit the new staircase, which usually takes a few days. We put up dust screens on the landing and plan noisy work for reasonable hours.
How long will a loft conversion take?
On a typical home, allow 6–10 weeks on site. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Where will the new staircase go?
The new staircase usually sits above the existing stairs, rising from the landing so it uses space that is already circulation. Sometimes it needs to come from a small bedroom or box room, which reduces that room's size. Building regulations set rules on headroom, step size and handrails, with some flexibility for lofts. We look at options at the survey and show you how each affects the floor below.
Do I need planning permission for a loft conversion?
Whether a loft conversion needs planning permission depends on its size and design, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. In England, many conversions fall under permitted development if the added volume is within 40m³ for terraced houses or 50m³ for other houses and nothing extends beyond the front roof slope. We check what applies before quoting.
Towns in Wiltshire
We offer a loft conversion in each of the towns below, all within Wiltshire. Select yours for guide prices, postcodes covered and nearby places.