Covering Swanley
Our coverage around Swanley (BR8) also includes Bexley, Dartford and Welling.
Homes in the South East
The South East has a lot of 1930s and post-war semi-detached housing, well suited to rear extensions and hip-to-gable loft conversions, alongside period properties in conservation areas that need a more careful design.
What is included in a mansard loft conversion in Swanley?
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
- Staircase, insulation and fit-out
- En-suite, electrics and fire safety
How much does a mansard loft conversion cost in Swanley?
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 |
Planning and building rules in Swanley
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 should I think about before starting?
- The roof is open for longer than with a dormer, so weather protection matters.
- Scaffolding and a temporary roof are usually needed.
What happens after I enquire?
- 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.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- 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.
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 Swanley?
Yes. Swanley is within our coverage for mansard loft conversions, along with nearby Bexley and Dartford.
Mansard loft conversions near Swanley
- Mansard loft conversions in Bexley
- Mansard loft conversions in Dartford
- Mansard loft conversions in Welling
- Mansard loft conversions in Eltham
Learn more about mansard loft conversions, or see every project we cover in Swanley.

