Covering Barnes
Alongside Barnes, we also cover Chiswick, Putney (2 miles to the south-east) and Fulham.
Homes in London
London projects often mean working on period terraces with neighbours on both sides, tight access through the house and conservation area controls, so careful planning and party wall work matter as much as the build.
What goes into a loft conversion?
A loft conversion turns an unused roof space into habitable rooms, usually a bedroom with an en-suite, by strengthening the floor, adding a staircase, insulating the roof and putting in windows. The type you need depends on the roof: rooflight, dormer, hip-to-gable or mansard.
- Design drawings and structural calculations
- New floor joists, steels and staircase
- En-suite, electrics, heating and fire safety upgrades
What is the guide price for a loft conversion in Barnes?
Indicative costs for loft conversions. London and the South East usually sit towards the top of each range.
| Loft conversions | Guide price incl. VAT |
|---|---|
| Rooflight conversion | £30,000 to £45,000 |
| Dormer conversion | £50,000 to £90,000 |
| Hip-to-gable with dormer | £60,000 to £95,000 |
| Mansard conversion | £65,000 to £110,000 |
What approvals does a loft conversion need in England?
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.
In England many loft conversions are permitted development: the extra roof volume must stay within 40 m³ on a terraced house or 50 m³ on a semi or detached house, nothing can sit higher than the existing ridge, no dormer can face a road on the main elevation, and side windows must be obscure-glazed and non-opening below 1.7 m.
What can change the price or programme?
- The new staircase usually takes space from the landing or a bedroom below.
- Party wall notices are often needed for steels bearing on a shared wall.
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.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- 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 loft conversion in Barnes
How long does a loft conversion take?
Usually 6 to 14 weeks on site depending on the type.
Do I need fire doors?
Often yes. Building regulations require a protected escape route from the new floor, which usually means fire doors on to the stairs and linked smoke alarms.
Can you visit a house in Barnes 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.
Loft conversions near Barnes
- Loft conversions in Chiswick
- Loft conversions in Putney
- Loft conversions in Fulham
- Loft conversions in Shepherd's Bush
Learn more about loft conversions, or see every project we cover in Barnes.

