Skylight costs
What is the average cost of skylights in the UK?
The short answer
There is no single average cost of a skylight in the UK that will hold for your roof, because the price follows the job, not the window. Swapping a unit in an opening that already exists is a lighter job than cutting a new one through the rafters, and access, the roof covering and VAT move the total again. We give one written total after a survey.
What pushes the price of a skylight job up or down, which typical figures are worth knowing, and how to compare two quotes fairly.
Swap or new opening: the biggest split in price
The unit itself is the smaller part of most skylight bills. What separates a lighter job from a heavier one is the work around the glass. Replacing an old roof window in the opening it already fills means lifting out the unit, setting the new one in the same position and renewing the flashing, the metal or moulded kit that keeps rain out around the frame. A new opening is another job altogether. The covering is stripped back, rafters are cut and trimmed with new timbers, the opening is lined and insulated, and the room below needs finishing.
The type of unit moves the figure too. A fixed pane is simpler than one that opens. An electric opening unit costs more than a manual one. On a flat roof, a rooflight or lantern is carried on a built upstand where a pitched roof would take a flashing kit. Size counts as well, because a larger unit means longer cuts, heavier framing and an extra pair of hands on the roof. Our guide to fitting a Velux roof window and what it costs sets a swap beside a new opening so you can see where the work differs.
Access and scaffold can outweigh the glass
Where the window goes decides how the roof is reached. A rear slope over a single-storey extension may be reachable with a roof ladder and a low platform. A front slope on a two-storey house normally needs scaffold, which is paid for whatever glass goes in. Checkatrade's scaffolding costs, in a table dated October 2026, are around £875 for a month on a semi with two storeys, £800 on a terrace, £1,000 on a detached bungalow and £1,200 on a detached house.
Those are typical UK figures, not a price for your street. Scaffold that blocks a public footway is licensed by whoever runs the roads. For West Sussex the minimum notice is 10 working days. Around Havant, Hampshire expects two full working weeks between the application and the start. When two roofers give you two totals, check whether scaffold sits inside each one before deciding which is the better price.
Roofer time and the covering you have
Labour is the third driver. In Checkatrade's roof repair figures, from a table dated June 2026, roofers are put at around £35 to £45 an hour, or £280 to £360 a day. A swap can be quick. A new opening is slower, since the rafters are cut, trimmed and sealed against the weather before anyone leaves the roof. Our answer on how long a roof window takes to fit goes through the stages.
The covering matters because the flashing must suit it. Plain tiles, interlocking tiles and slate each need a different flashing kit, and a slate roof is slower to cut around because every slate disturbed has to be reinstated neatly. A roof in poor condition adds its own question: if the tiles around the opening are tired, it is sensible to say so before the hole is cut. We look at the surrounding covering during the survey and tell you whether a repair around the window is enough.
VAT, approvals and the extras that surprise people
Per gov.uk, VAT is charged at a standard rate of 20 per cent. Some cost guides publish figures that leave it out. Checkatrade says under its repair figures that VAT is left out and has to be added, so a range copied from a website may sit well under what lands on your invoice. Ask every roofer whether the total includes VAT.
Approvals can add time and sometimes cost. A new opening is a structural alteration, which brings in building control, and a new or replacement roof window must also reach the heat-loss limits set by Approved Document L. Planning permission is usually not needed for a roof window on a house, but flats, listed buildings, side slopes and some conservation-area directions change that, as our guide to planning permission for a skylight explains. Choosing a unit that meets the thermal limit from the start avoids paying twice, and your building control body will ask for the rating on the data sheet either way.
Getting a total you can rely on
A good price starts with good information. Send photographs of the roof slope and of the room below, the size of the existing opening if there is one, and the covering if you know it. Our survey photographs each slope, and our written quote shows a single total price. The survey is what lets us put a firm figure on paper.
With two quotes laid next to each other, ask the same short questions of each. Is VAT in the total? Does it include scaffold, if the slope needs it? Does it cover finishing the inside of the opening, or only the roof? Is the flashing kit matched to your covering? An answer to those four questions tells you more than the headline figure. If a total looks far below the rest, the gap usually lies in one of them. The skylights and roof windows page sets out how we approach the whole job.
Related questions
Skylight price questions
Is a fixed skylight cheaper than one that opens?
The fixed unit has less to it than one with hinges and a mechanism, so the unit alone is usually the smaller price. The gap can be smaller than what scaffold or new framing adds. An opening unit gives ventilation, which suits a bathroom or a loft bedroom, so choose by the room first.
Does the price include plastering and decorating inside?
It depends on what the roofer has quoted for. Some totals stop at the roof, and others include lining the opening. Ask before you accept, and check that the written quote says which it is, so the finishing is not left for you to arrange.