Mansard loft conversions in Portsmouth

Covering Portsmouth

Portsmouth is about 15 miles south-east of Southampton. We also cover Gosport (2 miles to the west), Fareham and Ryde.

Homes in the South East

Many South East homes are inter-war or post-war semis and detached houses with room for rear and side extensions, while historic town centres and villages bring conservation area and listed building controls.

What do you get with a mansard loft conversion?

Mansards are a bigger structural job than other conversions because the roof is largely rebuilt. They normally need planning permission, and many councils have design guides setting the angle, materials and window style. We prepare the design to those guides and build in slate, lead and timber or approved alternatives.

Planning application to local design guidance
Roof removal and new mansard frame
En-suite, electrics and fire safety

What is the guide price for a mansard loft conversion in Portsmouth?

Indicative costs for mansard loft conversions. London and the South East usually sit towards the top of each range.

Mansard loft conversions	Guide price incl. VAT
Rear mansard	£65,000 to £85,000
Front and rear (double) mansard	£80,000 to £110,000

How is a mansard loft conversion approved in Portsmouth?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.

Mansard conversions change the shape of the roof significantly, so they usually need planning permission in England. Many councils publish guidance on mansard design.

What should Portsmouth homeowners check first?

A mansard nearly always involves party walls on both sides of a terrace.
The roof is open for longer than with a dormer, so weather protection matters.

What are the steps?

Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Questions about a mansard loft conversion in Portsmouth

How much does a mansard loft conversion cost?

Typically £65,000 to £110,000 including VAT, depending on whether one or both roof slopes are rebuilt.

Why choose a mansard over a dormer?

A mansard gives more usable space and often fits a street better where neighbours already have one.

Do you work in Portsmouth?

Yes. Portsmouth is within our coverage for mansard loft conversions, along with nearby Gosport and Fareham.

Mansard loft conversions in nearby towns

Learn more about mansard loft conversions, or see every project we cover in Portsmouth.