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RooflightInstallers.co.uk
Portishead · BS20 · Somerset

New rooflight in an existing roof in Portishead

New rooflight in an existing roof in Portishead comes down to what happens around the glass. A good unit sat on a poor upstand, or with the membrane or flashing cut short at the corners, will still let water in. We fit each rooflight to the maker's instructions for fixings, packers and sealant, for homes and businesses across Portishead and the rest of Somerset. That covers supply and fit, fit-only for a unit you already own, and swapping out a tired one. Every job starts with a written quote, so the price and scope are clear before anyone climbs a ladder.

Guide price from £2,295 · Supply & fit, including structure and making good; building control or warrant fees extra

What the job costs in Portishead

Small fixed unit

£2,295 – £3,345including VAT at 20%

Opening cut, joists trimmed, upstand built, roof covering made good, plasterboard reveals ready for decoration

Medium fixed unit

£3,345 – £4,795including VAT at 20%

As the small unit, with a larger opening up to about 1 × 2 m and additional trimming

Large or opening unit

£4,795 – £7,795including VAT at 20%

Bigger structural work or an electric opening unit

Guide ranges for supply & fit, including structure and making good; building control or warrant fees extra. Your price is fixed in a written quote after we have seen photos or surveyed. Scaffold, access towers or a crane are priced separately if the job needs them, and building control fees, where a job needs them, are shown as their own line.

Coverage in and around Portishead

Covering Portishead means covering the people who live and work there, not a single postcode. We take on domestic and commercial jobs in BS20, BS48 and BS21, and are happy to quote further out in Nailsea and Clevedon. If your address sits between towns, tell us and we will confirm whether it falls in our normal area or needs travel set out separately on the quote.

Already bought your unit?

Your unit or ours, the fitting standard is the same. For supply and fit we choose a new rooflight to suit the roof and price it with the installation. For fit-only we work with what you have, after confirming it arrived undamaged, that it matches the builder's opening, and that the upstand will sit at the height the maker asks for. Report any transit damage to the seller, as the product cover is theirs and the maker's. Our written guarantee applies to the fitting itself.

What we do on the day

  • Opening marked out, covering stripped back and the deck cut cleanly
  • Insulated upstand built square, level and to the maker's height
  • Survey of joist direction, roof build-up, ceiling void and access
  • Planning for your roof — We check whether the new rooflight falls within permitted development for your house and nation.
  • Upstand energy performance — We build the upstand to meet the energy limit for site-built upstands, not just to hold the rooflight up.

What happens on the day

Arrive and agree the plan. Sheet the floor and furniture. Set up the ladder, tower or scaffold. Check the opening, the upstand or flashing, and the unit against the paperwork. Fix and pack a new rooflight level. Seal it into the roof. Line the reveal or fit the ceiling trim. Clean the glass, clear the waste, and talk you through it. That is the shape of most fitting days, and for this type of job it usually takes two to three days.

Do you need permission in Portishead?

England's rules in short: permitted development usually covers a rooflight on a house roof provided it doesn't stick out more than 0.15 m or rise above the ridge, though a listed building always needs consent and some streets have Article 4 directions. Building regulations apply to new openings, and replacements go through building control; as we are not registered with a competent person scheme, we use a building notice and show the fee on the quote. The energy limit for rooflights in existing homes is 2.2 W/m²K, and the 2026 Approved Document L, in force from 24 March 2027, keeps that figure.

Details that speed up your quote

What we cannot see, we have to guess, and guesses make quotes wider. So the more you send, the tighter the price. Useful: shots from the roof or garden, shots from the room underneath, a rough width and length, the roof finish, any access problems, and the product page if you have already ordered. Add the property postcode around BS20 and we will come back with a quote or a survey date.

Common questions in Portishead

Will my new rooflight leak?

A correctly fitted unit should not. Leaks usually trace back to the detail around the frame: an upstand that is too low, a membrane or flashing that is not dressed properly, sealant applied to a damp surface, or water ponding against the kerb. We fit to the maker's instructions and check each of those points. The fitting carries a written workmanship guarantee, with its terms set out on your quote.

Do I need planning permission for a rooflight in Portishead?

Often not. Many rooflights fall under permitted development, provided they do not project beyond the national limit and meet the other conditions that apply in England. Conservation areas, listed buildings and some flats are different and may need consent. Because the rules depend on the property, we confirm what is likely to apply at your address and point you to the planning authority where an application is needed.

What is included in the price?

The written quote lists it line by line. Typically that covers fitting labour, fixings, sealants, membrane or flashing materials, any upstand work, internal finishing if agreed, and taking away the waste. For supply and fit, the unit itself is included too. Scaffold, lifting gear and any third-party fees, where needed, are shown separately so you can see what each part of the job costs.

Planning a new rooflight in Portishead? Tell us about the roof and we will come back with a clear price in writing.

Rear extension at dusk with lit rooflights and a roof lantern
Ready when you are

New openings in Portishead

Send photos and rough sizes, or ask for a survey for install work. One fixed written price before anything starts.

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