What is a rooflight loft conversion?

A rooflight loft conversion (sometimes called a roof window conversion) keeps the existing roof shape and adds roof windows that sit flush with the slope. The floor is strengthened, a staircase is added and the space is insulated and finished.
How much does a rooflight loft conversion cost in Bexleyheath?
In Bexleyheath, a rooflight loft conversion typically costs £39,000–£58,500 for a typical rooflight conversion, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for London, where labour and materials are typically about 30% above average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £39,000–£58,500 |
| Higher specification | £58,500–£73,000 |
The biggest cost drivers are:
- Bathroom or not
- Storage and finishes
- Fire safety upgrades
- Staircase position
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a rooflight loft conversion in Bexleyheath?
Whether you need planning permission depends on your house and its location in England. In England roof windows are permitted development if they project no more than 15 centimetres from the roof slope and side-facing windows are obscure-glazed. Listed buildings need consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Floor joists and any steel beams
- Drawings and structural calculations
- Building control sign-off
- Insulation between and under rafters
- Roof windows installed
- Head-height survey
How long does it take?
Expect 4 to 6 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Bexleyheath
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
We work across Bexleyheath and neighbouring areas such as Welling, Erith and Sidcup. Postcodes we cover in Bexleyheath include DA6 and DA7.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about rooflight loft conversions in Bexleyheath
Who approves a rooflight loft conversion in Bexleyheath?
Planning matters in Bexleyheath go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
How much does a rooflight loft conversion cost in Bexleyheath?
In Bexleyheath, a rooflight loft conversion typically costs £39,000–£58,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
