Velux & Rooflight
Velux and Rooflight Loft Conversions in Bromley
The lowest-cost loft conversion, because nothing about the shape of the roof changes.
The Conversion That Leaves the Roof Alone
A rooflight conversion, usually called a Velux conversion after the best-known brand of roof window, is what you build when the roof is already tall enough. No dormer, no gable, no change to the outline of the house from the street. The work happens inside: strengthening the floor, insulating, plastering, putting in a staircase, and cutting in roof windows that sit flush with the tiles.
Because there is no structural alteration to the roof, it is dramatically cheaper than everything else on this site, and dramatically less disruptive. If your loft already has the head height, this is the conversion to ask about first.
Do You Have Enough Head Height?
The rough test is whether you can stand comfortably along a decent width of the loft, not just at the ridge.
Here is the honest version of a rule you will see stated as law everywhere: there is no minimum loft head height in the building regulations. The figure people quote, 2.2 metres, is an industry rule of thumb, not a legal threshold. What the regulations do set is a headroom requirement over the staircase: normally 2 metres, and specifically for loft conversions, a reduced 1.9 metres at the centre of the stair and 1.8 metres at the side where there is not enough space for the full 2 metres.
So the real question is not "do I have 2.2 metres" but "is there enough height, in the right places, for a room and a compliant staircase". That is a survey question, and a good surveyor will tell you in ten minutes.
Can you do a loft conversion for £20,000? Not in Bromley, and this is the type people are usually thinking of when they ask. The entry point here is around £28,000. Anyone quoting materially under that is either not including the staircase, not including building control, or not doing what you think they are doing.
What the Work Involves
Floor Strengthening
New joists on steels or on the existing walls, so the floor carries a room rather than boxes.
Insulation
Between and over the rafters, to current standards. This is a bigger part of the job than people expect.
Roof Windows
Cut in flush with the tiles, with proper flashing kits. No change to the roof outline.
Staircase
The main structural intervention in this type, and the thing that decides whether it works.
Fire Safety
Doors, alarms and a protected escape route, required whether or not the roof shape changes.
Plaster, Electrics, Heating
And building control sign-off.
Velux & Rooflight Costs in Bromley
| Conversion type | Estimated cost in Bromley |
|---|---|
| Velux / rooflight | £28,000 – £38,000 |
Figures are estimates for guidance only, based on published 2026 ranges and prices advertised locally. Every loft is different. The only accurate number is a quote from a surveyor who has been up in yours.
Planning Permission for a Rooflight Conversion
Rooflights fall under Class C, not Class B, and this is the single most useful distinction in loft-conversion planning: Class C carries no conservation-area exclusion. Class B roof extensions are switched off entirely on designated land. Rooflights are not, so in most of Bromley's 47 conservation areas, a flush rooflight conversion can still be permitted development where a dormer would need a full application.
With two named exceptions in this borough. The Article 4 direction of 19 July 2022 removes Class C in the Chislehurst Road Conservation Area, and removes both Class B and Class C in the Petts Wood Area of Special Residential Character. In those two places, rooflights need permission.
That is the kind of detail a national guide will get wrong about your address. Check yours before you plan around it.
This is general information, not planning advice. Permitted development rights depend on your specific property, what has already been built, and whether the address falls in a conservation area or under an Article 4 direction. Check your address on Bromley Council's own map, and take professional advice before committing to anything.
Why Start Here
We are Not Quoting You
We do not carry out the work, so we gain nothing from talking you into a bigger conversion than your roof needs. A building company quoting you is in a different position.
Specialists Who Cover Your Postcode
Your enquiry goes to loft conversion companies actually working in your part of the borough and currently taking work, not a national list.
Bromley Rules, Not National Boilerplate
Forty-seven conservation areas and an Article 4 direction that removes rights most guides assume you have. We cover what applies here.
Nothing Owed, Nothing Booked
Quotes are free and there is no obligation at any point. On a job this size, take two or three of them.
Find Out What Your Loft Conversion Would Cost
Tell us about your house and what you want the loft for. We will pass it to loft specialists covering your area, and they will come back to you with a quote. No obligation, no pressure.
Areas We Cover for Velux & Rooflight Conversions
Rooflight conversions depend on the height you already have rather than the shape of the house, so they come up right across the borough.
Other Conversion Types
Not sure this is the right conversion for your house? The other types are below, and the types of loft conversion guide compares them properly, including the lofts that cannot be converted at all.