How we approach flat rooflights in Cardiff
Our flat rooflights service in Cardiff covers fixed double or triple glazed rooflights for flat roofs and extensions. Every job starts with a survey of the opening, the roof covering and the room below, and a fixed written price.
Welsh planning rules exclude rooflights from permitted development in conservation areas and National Parks, so we check the designation before quoting. Flat rooflights suit kitchen extensions, side returns and flat-roofed back rooms.
We cover all of Cardiff and the CF10 district, and nearby Penarth and Dinas Powys.
Choices for your Cardiff project
- Square, rectangular or long-format sizes
- Insulated kerb or timber upstand built to suit
- Integral or fitted blinds
- Solar-control or self-cleaning outer pane
- Rain sensor if paired with an opening unit
- Double or triple glazed with a warm-edge spacer
- Even, top-down daylight across the whole room
Before you order: points to check
- New openings in an existing roof need a structural check on joists
- The roof membrane must be dressed up the upstand before the unit goes on
Planning and building rules for Cardiff
Welsh householder permitted development (Class C) allows rooflights that project no more than 15 cm and sit no higher than the existing roof — but not in conservation areas, National Parks, AONBs or World Heritage Sites. Listed buildings need listed building consent from the council, and flats have no householder permitted development rights.
Approved Document L in Wales (2022 edition) sets 2.2 W/m²K for rooflights, measured horizontally, and 1.4 W/m²K or Band B for roof windows in existing homes. A revised Welsh Approved Document L takes effect on 4 March 2027; rooflights in new dwellings stay at 2.2 W/m²K.
Read the planning permission guide before you commit to a design.
Guide prices for Cardiff
Guide prices for flat rooflights in Cardiff are the same as anywhere we work — what changes the price is the job: access, structure, scaffold and finishing.
| Option | Guide price inc VAT | Ex VAT |
|---|---|---|
| Large or triple glazed (1500 × 2500 mm and up) | £2,395 – £4,195 | £1,995 – £3,495 |
| Mid-size double glazed (1000 × 2000 mm) Typical | £1,675 – £2,395 | £1,395 – £1,995 |
| Small double glazed (up to 1000 × 1000 mm) | £1,195 – £1,795 | £995 – £1,495 |
How the job runs
- Send the details. Postcode, rough size and a photo of the roof and room.
- Free site visit. For new installs we survey free, measure and confirm the roof detail.
- Fixed quote. Product, work and price in writing — nothing is ordered until you agree.
- Installation day. Usually one day into a prepared opening, longer for new openings.
Neighbouring towns
Other services in Cardiff
Common questions
Can a flat rooflight be walked on?
Not unless it is designed as a walk-on unit with structural laminated glass. A standard flat rooflight is for light only — if the roof is used as a terrace, choose a walk-on rooflight instead.
Do flat rooflights leak?
A well-fitted flat rooflight should not leak. Leaks almost always come from the upstand or membrane detailing, not the glass unit, which is why the upstand height and the way the roof covering is dressed up and under the frame matter more than the brand.
Will it make the room too hot?
A big unglazed-to-sky area can add solar gain in summer. Solar-control glass, a blind, or pairing a fixed unit with an opening one keeps it comfortable.
Is the survey in Cardiff free?
Yes for new installations. Repair visits are charged, and we tell you the price before we book.
How do I book a survey in Cardiff?
Send your postcode and, if you can, a photo of the roof and the room. We offer a survey date when we reply.
