What is a mansard loft conversion?
A mansard loft conversion rebuilds the roof with a nearly vertical slope (about 72 degrees) and a flat top, effectively adding a new storey. Small dormer windows sit within the steep slope. Mansards are common on period terraces in towns and cities.
How much does a mansard loft conversion cost in Bournemouth?
In Bournemouth, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Bournemouth reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £66,500–£97,000 |
| Higher specification | £97,000–£121,000 |
What moves the price most:
- Roof covering: natural slate costs more
- Party wall surveyor fees
- Bathrooms and finishes
- Front, rear or both
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a mansard loft conversion in Bournemouth?
Before anything is built in Bournemouth, we confirm which approvals apply in England. In England a mansard almost always needs planning permission because it changes the roof shape. Many councils publish design guidance for mansards on terraced streets, and some streets are more likely to be approved where neighbours already have one.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most mansard loft conversions:
- Building control sign-off
- New roof structure, slate or tile covering and lead work
- Staircase and fire-safe escape route
- Insulation, electrics, plumbing and plastering
- Dormer windows
- Planning drawings and application
How long does it take?
Allow 9 to 12 weeks on site, after planning approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Bournemouth
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
We work across Bournemouth and neighbouring areas such as Christchurch, Poole and New Milton. Postcodes we cover in Bournemouth include BH1, BH2, BH7 and BH10.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about mansard loft conversions in Bournemouth
Do you build mansard loft conversions in Bournemouth?
Yes. We build mansard loft conversions across Bournemouth, including postcodes BH1, BH2, BH7 and BH10. Every project starts with a free home visit.
How much does a mansard loft conversion cost in Bournemouth?
In Bournemouth, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
Why choose a mansard over a dormer?
A mansard gives more usable floor space and a neater appearance from the street, but costs more and needs planning permission.