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.
If you live in Trowbridge and are weighing up a loft conversion, the starting point is a visit to measure up and talk through what you want, which costs nothing. We cover homes across BA14, and a typical project of this kind in the South West lands somewhere in the £30,500–£66,000 bracket, including VAT. The exact figure depends on size, access and the finish you choose.
- Guide price
- £30,500–£66,000 inc VAT
- Time on site
- 6–10 weeks on site
- Postcodes
- BA14
- Planning rules
- England
- Local area
- Wiltshire
- Survey
- Free, with a written quote
Loft conversions prices in Trowbridge
Use the table to gauge the cost of a loft conversion in Trowbridge 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 Trowbridge |
|---|---|---|
| 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 |
Expect these to shape the final quote:
- Floor area, existing head height and roof structure
- 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’s included?
- New floor joists strong enough for a habitable room
- Dormer, hip-to-gable or rooflight structure as agreed
- Insulation to walls, roof slope and floor
- 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
What are homes like around Trowbridge?
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.
Knowing the typical building types in Wiltshire helps, but a survey of your own home in Trowbridge is what decides the right approach to a loft conversion.
Permissions for a loft conversion in Trowbridge
As Trowbridge is in England, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
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.
What happens after you get in touch?
Survey and measure
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.
Price and scope agreed
After the survey we send a quote for a loft conversion that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Booking the work
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Trowbridge property.
The work itself
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.
How we work
Questions about a loft conversion in Trowbridge
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.
Can I put a bathroom in my loft?
A bathroom or shower room can usually be added in a loft conversion if waste pipes can reach the soil stack with enough fall, or a pumped system can be used. Dormers make this easier because they give standing height for a shower. Water pressure, extraction and the position of the boiler also matter. We plan the bathroom layout at the design stage so pipes are hidden in the structure.
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.
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.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a loft conversion, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
Also covering areas around Trowbridge
Coverage for Trowbridge spans BA14. Close by, Melksham, Bath and Frome are covered too, and the rest of our UK-wide area follows the same survey-then-quote process from start to finish.