Covering Feltham
Feltham sits 13 miles west of London, with Hanworth 2 miles to the south-east and Ashford 2 miles to the south-west.
Homes in London
Much of London’s housing is Victorian and Edwardian terraces, which is why side return extensions, rear dormers and mansards are so common. Many streets are in conservation areas, and several boroughs use Article 4 directions that remove some permitted development rights.
What is included in a mansard loft conversion in Feltham?
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
- Structural design and party wall process
- Staircase, insulation and fit-out
How much should I budget for a mansard loft conversion?
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 |
Planning and building rules in Feltham
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?
- Council design guides often require natural slate and lead.
- Scaffolding and a temporary roof are usually needed.
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.
- 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.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Questions about a mansard loft conversion in Feltham
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.
How long does a mansard take?
Around 10 to 14 weeks on site after planning approval.
Do you work in Feltham?
Yes. Feltham is within our coverage for mansard loft conversions, along with nearby Hanworth and Ashford.
Mansard loft conversions near Feltham
- Mansard loft conversions in Hanworth
- Mansard loft conversions in Ashford
- Mansard loft conversions in Hounslow
- Mansard loft conversions in Sunbury-on-Thames
Learn more about mansard loft conversions, or see every project we cover in Feltham.

