Covering New Malden
Our coverage around New Malden (KT3) also includes Surbiton, Morden and Wimbledon.
Homes in London
Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.
What is a mansard loft conversion?
A mansard loft conversion replaces one or both slopes of a roof with a near-vertical wall, typically at 70 degrees, with small dormer windows set into it. It creates almost a full extra storey and is common on terraced houses in towns and cities, particularly in London.
- Planning application to local design guidance
- Structural design and party wall process
- Staircase, insulation and fit-out
How much does a mansard loft conversion cost in New Malden?
Guide prices for mansard loft conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.
| Mansard loft conversions | Guide price incl. VAT |
|---|---|
| Rear mansard | £65,000 to £85,000 |
| Front and rear (double) mansard | £80,000 to £110,000 |
What approvals does a mansard loft conversion need in England?
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.
What are the steps?
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
What people ask before starting
How long does a mansard take?
Around 10 to 14 weeks on site after planning approval.
Will I need party wall agreements?
Very likely, as the work affects the walls shared with both neighbours on a terrace.
Do you work in New Malden?
Yes. New Malden is within our coverage for mansard loft conversions, along with nearby Surbiton and Morden.
Mansard loft conversions in nearby towns
- Mansard loft conversions in Surbiton
- Mansard loft conversions in Morden
- Mansard loft conversions in Wimbledon
- Mansard loft conversions in Ewell
Learn more about mansard loft conversions, or see every project we cover in New Malden.

