Flat rooflights for Llantwit Major: the essentials
Flat rooflights in Llantwit Major means fixed double or triple glazed rooflights for flat roofs and extensions. We cover the CF61 district and the rest of South Glamorgan, with a survey before any price is fixed.
Welsh planning rules exclude rooflights from permitted development in conservation areas and National Parks, so we check the designation before quoting. In Llantwit Major, as anywhere, flat rooflights are the usual choice for landings, bathrooms and rear extensions with flat roofs.
From Llantwit Major to Cowbridge, Bridgend and Barry, the same survey-first process applies: measure, specify, fix the price, then fit.
Specification options
- Double or triple glazing
- Rain sensor if paired with an opening unit
- Square, rectangular or long-format sizes
- Plastered or lined internal reveal
- Insulated kerb or timber upstand built to suit
- Inner pane laminated for safety overhead
- Fixed units are simple, quiet and low-maintenance
Things we check at survey
- The roof membrane must be dressed up the upstand before the unit goes on
- New openings in an existing roof need a structural check on joists
Do you need permission in Llantwit Major?
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. A side-facing rooflight within 10.5 m of the boundary must be obscure-glazed, and non-opening unless the opening part is more than 1.7 m above the floor.
Welsh Building Regulations expect new or replacement rooflights to reach 2.2 W/m²K and roof windows 1.4 W/m²K or a Band B rating. A revised Welsh Approved Document L takes effect on 4 March 2027; rooflights in new dwellings stay at 2.2 W/m²K.
See our building regulations guide for U-values, glazing limits and self-certification.
Flat rooflights prices in Llantwit Major
Guide prices for flat rooflights in Llantwit Major 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.
- Survey. We measure the opening, check the roof build-up and agree the options.
- Written price. You receive a fixed price listing the unit, the work and the lead time.
- Fit and make good. We fit, seal, test and finish the reveal, then hand over the paperwork.
Nearby towns
Related work in Llantwit Major
Questions about flat rooflights in Llantwit Major
Double or triple glazing?
Double glazing suits most domestic jobs. Triple glazing improves thermal performance and cuts noise from rain, which is worth it over bedrooms or where the energy calculation is tight.
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.
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 I need planning permission in Llantwit Major?
In Wales a rooflight on a house is usually permitted development if it stands no more than 15 cm proud of the roof, except on protected land such as conservation areas and National Parks, where permission is needed.
Is the survey in Llantwit Major free?
Yes for new installations. Repair visits are charged, and we tell you the price before we book.
