What do flat rooflights in Portsmouth involve?
Our flat rooflights service in Portsmouth 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.
Many South East homes have been extended more than once, and an old dome over an earlier extension is often due for replacement. Flat rooflights suit kitchen extensions, side returns and flat-roofed back rooms.
Portsmouth sits about 3 km from Gosport and 9 km from Fareham, and we cover the whole PO1 postcode district and the roads in between.
Options we can specify in Portsmouth
- Plastered or lined internal reveal
- Frame colours: anthracite, black, white or RAL
- Double or triple glazing
- Square, rectangular or long-format sizes
- Rain sensor if paired with an opening unit
- Pairs with an opening unit where you also need ventilation
- Even, top-down daylight across the whole room
Things we check at survey
- Rooflights count toward glazing in an extension, which matters for Building Regulations energy and overheating rules
- The roof membrane must be dressed up the upstand before the unit goes on
Planning and building rules for Portsmouth
In England a rooflight on a house is usually permitted development under Class C if it projects no more than 150 mm beyond the roof slope and sits no higher than the ridge. 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.
Building Regulations Approved Document L sets a limiting U-value of 2.2 W/m²K for new or replacement rooflights in existing homes, measured in the horizontal plane; roof windows need 1.4 W/m²K or a Band B energy rating. In an extension, glazing including rooflights is normally limited to 25% of the new floor area plus any windows or doors the extension covers, unless a whole-house calculation shows otherwise.
See our building regulations guide for U-values, glazing limits and self-certification.
Guide prices for Portsmouth
Guide prices for flat rooflights in Portsmouth 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 |
What happens next
- Tell us what you have. Send the PO1 postcode, a rough size and a couple of photos.
- Free site visit. For new installs we survey free, measure and confirm the roof detail.
- Agree the quote. You approve the specification and price before anything is ordered.
- Installation day. Usually one day into a prepared opening, longer for new openings.
Nearby towns
Other services in Portsmouth
Flat rooflights in Portsmouth: questions
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.
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.
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.
How do I book a survey in Portsmouth?
Send your postcode and, if you can, a photo of the roof and the room. We offer a survey date when we reply.
Is the survey in Portsmouth free?
Yes for new installations. Repair visits are charged, and we tell you the price before we book.
