Mansard loft conversions in Horsham

Covering Horsham

Horsham is about 7 miles south-west of Crawley. We also cover Crawley (7 miles to the north-east), Horley and Haywards Heath.

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.

Structural design and party wall process
Roof removal and new mansard frame
Staircase, insulation and fit-out

What will a mansard loft conversion cost?

Use these ranges to budget for mansard loft conversions; the survey turns them into a fixed price for the agreed specification.

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

Do you need permission for a mansard loft conversion in Horsham?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it 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 can affect a mansard loft conversion?

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.

How does the project run?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
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.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Mansard loft conversions: common questions

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.

Can you visit a house in Horsham to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Mansard loft conversions near Horsham

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