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 are planning a loft conversion anywhere in Dorset, including Bournemouth, Poole, Weymouth and Christchurch, we can visit, measure up and talk through the options. The planning and building regulations we work to are those for England, and we check them for your address before quoting. Prices remain guide figures for the South West, at £30,500–£66,000 including VAT, until the survey is done.
- 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
- 4
- Survey
- Free, with a written quote
How much does a loft conversion cost in Dorset?
Every figure below is a guide for a loft conversion in Dorset, inclusive of VAT. Regional pricing for the South West works out about 2% above the national guide, and the overall span is £30,500–£66,000. The survey costs you nothing, and after it we commit to a firm price for your specification in writing.
| Type of job | What it usually involves | Guide in Dorset |
|---|---|---|
| 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 |
What moves the price up or down:
- Conversion type: rooflight, dormer, hip-to-gable or mansard
- Floor area, existing head height and roof structure
- Adding a shower room or en-suite in the roof
- Staircase layout, fire doors and the level of finishes
Scope of the work
- Structural calculations and steel beams where needed
- Dormer, hip-to-gable or rooflight structure as agreed
- Staircase designed to fit your landing and meet regulations
- 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
Homes in Dorset
Dorset's older villages use Purbeck and Portland stone, chalk and flint, and thatch on cob or brick cottages. Bournemouth and Poole have Victorian and Edwardian villas, large interwar suburbs and plenty of bungalows and flats, while Weymouth, Dorchester and Bridport mix Georgian and Victorian streets with newer estates.
Stone and thatched cottages may need lime repairs and conservation-area window choices. Bungalows around Bournemouth and Poole commonly suit loft conversions, and coastal homes often need roofline, rendering and window renewal.
Salt spray and south-westerly winds affect coastal homes, so external finishes and fixings need to cope with marine exposure.
Do you need permission in Dorset?
As Dorset 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.
How does the job run?
Free site survey
We arrange a free site survey on a date convenient to you. We measure up, look at the existing structure and access, and discuss your plans for a loft conversion so the price reflects your home.
Price and scope agreed
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a loft conversion.
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.
On site to finish
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
How we work
Questions about a loft conversion in Dorset
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.
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.
What fire safety measures does a loft conversion need?
A loft conversion needs a safe way out in a fire, because the new room is high above the ground. This usually means a protected stair route down to an exit, with fire doors onto the stairway, mains-linked smoke alarms on each floor and sometimes an escape window. The exact approach depends on your house layout. Building control checks these measures before signing off the work.
Do I need planning permission in Dorset?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. Dorset is in England, so England's rules apply. Many smaller jobs need no planning application, but some still need building control approval. We check what applies to your address before quoting.
Is the price fixed?
Yes, for the specification we agree. Your written quote sets out exactly what is included at a fixed price. It only changes if you ask for something different, or if a problem the survey could not reasonably reveal later needs extra work. In either case we explain the change and confirm it in writing before going ahead.
Towns in Dorset
These are the towns in Dorset where you can book a free survey for a loft conversion. Each has its own page with guide prices and coverage details.