Flat rooflights in St Austell: what is involved?
Flat rooflights in St Austell means fixed double or triple glazed rooflights for flat roofs and extensions. We cover the PL25 district and the rest of Cornwall, with a survey before any price is fixed.
Many South West towns mix Georgian and Victorian terraces with modern estates, so the right product differs street by street. Flat rooflights suit landings, bathrooms and rear extensions with flat roofs.
From St Austell to Bodmin, Truro and Newquay, the same survey-first process applies: measure, specify, fix the price, then fit.
Options we can specify in St Austell
- Square, rectangular or long-format sizes
- Plastered or lined internal reveal
- Insulated kerb or timber upstand built to suit
- Rain sensor if paired with an opening unit
- Integral or fitted blinds
- Inner pane laminated for safety overhead
- Double or triple glazed with a warm-edge spacer
Things we check at survey
- New openings in an existing roof need a structural check on joists
- Needs a properly formed upstand — usually at least 150 mm above the finished roof surface (check the manufacturer's figure)
Consents for flat rooflights in St Austell
Most rooflights on English houses do not need planning permission, provided they keep within 150 mm of the roof surface and below the ridge line. A rooflight on a side-facing slope must be obscure-glazed, and fixed shut unless the opening part is more than 1.7 m above the floor.
Under Approved Document L, a rooflight added to an English home must achieve at least 2.2 W/m²K (horizontal plane), and a roof window 1.4 W/m²K or Window Energy Rating Band B. The Future Homes and Buildings Standards, published in March 2026, apply from 24 March 2027 and keep the 2.2 W/m²K limit for rooflights.
See our building regulations guide for U-values, glazing limits and self-certification.
What do flat rooflights cost in St Austell?
The ranges below are typical for straightforward jobs; your fixed price follows a survey of your roof.
| 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 |
The process, step by step
- Get in touch. Use the form, WhatsApp or the guide-price tool with your St Austell address.
- Measure and check. A surveyor visits St Austell, measures and checks structure and access.
- Fixed quote. Product, work and price in writing — nothing is ordered until you agree.
- Fit and make good. We fit, seal, test and finish the reveal, then hand over the paperwork.
Flat rooflights near St Austell
Other services in St Austell
Common questions
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.
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.
Can you fit into my existing flat roof?
Yes. We form a new opening, trim the joists, build and waterproof an upstand and make good the ceiling. A survey confirms the joist direction and roof build-up first.
How do I book a survey in St Austell?
Send your postcode and, if you can, a photo of the roof and the room. We offer a survey date when we reply.
Do I need to be at home for the survey in St Austell?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
