Ask five people what a roof window costs and you will hear five different numbers, all of them honest. A basic replacement in the same opening, with easy access, is a modest job. A new window in an untouched roof, with structural trimming, a larger size, electric opening and scaffold is another thing entirely. This guide sets out the published ranges we can point to, explains what makes up the price, and gives you a checklist for comparing quotes. It does not give a Beacon price list, because we do not have one: a roof window is priced after we have seen the roof.
The published figures
Two sources are worth knowing about, and they are not measuring the same thing. A trade-facing cost guide reports that a standard centre-pivot roof window, supplied and fitted, usually lands somewhere from £680 up to £1,300. A manufacturer's consumer cost article gives indicative figures of £1,623 to replace an existing roof window and £1,906 for a new opening, VAT included. Both are national figures, so neither reflects Basingstoke prices or the details of your roof. The gap between them says something useful: the cost depends on what is included and on whose labour and margins are in the number.
Treat these as orientation. They tell you the order of magnitude and show that a quote of a few hundred pounds probably leaves something out, while a quote of several thousand for a single standard window needs explaining. The quote you receive after the survey is fixed and written down, so every item is listed.
What is in the price
A fitted roof window quote normally bundles several things:
- The window itself: frame, sash, glazing and hardware, in a given size, finish and glazing type.
- The flashing kit, matched to the covering, including the underlay collar and, ideally, an insulation collar. Roof window flashing kits explained describes them.
- Labour for removing the old window or forming the opening, fitting the new frame and re-laying tiles or slates around it.
- Structural work: trimmers, doubled rafters and any support for a wider opening.
- Internal finishing: the lining, the plasterboard reveals, and decorating, or a lining kit supplied with the window.
- Access: scaffold or a tower, if the work cannot be done from the loft side or a ladder.
- Waste: taking away the old window, tiles and debris.
- Building control, where notification or a fee is needed.
What pushes the price up
Size. A bigger window costs more for the unit, uses larger trimmers and needs more tiling around it. The step from a standard size to a large one is more than the glass.
Glazing. Standard double glazing is the base. Noise-reducing, solar control, toughened or laminated glass, and triple glazing each add cost. Laminated inner panes are needed above stairs, where safety glass is expected.
Opening style and operation. A top-hung window or a combination of a window and a balcony system costs more than a centre-pivot. Electric or solar-powered operation adds the motor, the wiring and sometimes a rain sensor. Our answer on whether electric roof windows are worth it goes through the trade-off.
Finish. White-painted, polyurethane-coated and clear-lacquered pine have different prices, and so do aluminium and conservation-style frames. A metal-framed conservation unit costs more than a standard window. See conservation rooflights and roof window types for the options.
Roof covering. Plain clay tiles and natural slate take longer to cut and fit around a frame than concrete interlocking tiles, and lead flashing is slower than an aluminium kit, though it can be the better answer on a period roof.
Access and height. A window in a bungalow roof can be reached from a ladder. One on the third storey needs scaffold, which is a significant item. One cost guide gives roofline scaffold hire a typical UK range of £200 to £2,600 depending on the house, so sharing a scaffold with other roofing work saves money.
The number of windows. A second window fitted in the same visit costs less than the first, because the travel, the set-up and the scaffold are shared. Fitting several at once is the cheaper way to do a loft conversion's roof lights.
Replace or add: why the cost differs
Replacing a window in the same opening is the cheaper job, because the hole already exists, the trimmers are in place, and the lining is there. The labour is mostly removing, refitting and re-flashing. Adding a window means opening the roof: stripping tiles, cutting rafters, fitting trimmers, forming the opening, and making good inside, and then the same fitting and flashing work. Building control is also involved in a new opening in a way that it often is not for a like-for-like swap. The manufacturer's two figures reflect that difference. Our guide to replacing an old roof window and our answer on whether you can put a roof window in any roof cover each case.
Hidden costs to ask about
Some items are easy to leave out of a headline price, and it pays to ask about them before you accept a quote. Is scaffold included? Is the lining supplied and fitted, or left for you to finish? Who decorates? Is the building control fee included, or is it extra? What happens if the rafters are found to be rotten when the roof is opened? Does the price cover a new flashing kit or only the window? Will the old window and the waste be taken away? Do blinds, which are made for a specific window model and fitted inside, come with it? We list all of these in our fixed written quote, so that the number is the number.
Regulations and permissions that affect cost
A new opening needs Building Regulations approval, which brings the structural work, the energy standard and any escape requirement. The energy table in Part L 2021 sets out what an existing home's replacement roof window has to achieve, and a mainstream modern double-glazed unit normally clears it. A loft room that relies on a roof window as an escape may need a bigger window and a lower sill than a standard one, and a house of more than one storey above ground may need a stair instead. Planning permission is normally not needed for a window in an ordinary house, but conservation areas and listed buildings can change that. Our pages on roof windows and Building Regulations and planning permission for a skylight explain both.
Timing and how the work affects the bill
The time the job takes drives labour cost, and the time depends on the weather as much as on the window. A fitter will not open a roof in rain, so a booked day can slip, and a scaffold on hire during the delay costs more. Planning a window for a settled spell, and letting us choose the day within a range, usually keeps the cost down. Combining the window with other roof work is the best saving of all. If the roof covering is due to be renewed, fitting the window during the re-roof avoids cutting into a roof you are about to strip, and the flashing is laid with the new battens and underlay as one continuous job. Our guide on when to replace a roof helps you decide whether that applies to you.
The state of the structure can change the bill too. If a rafter or a trimmer is rotten when the covering comes off, it has to be repaired before the window goes in, and that is an extra we flag in writing when it happens. The same goes for a damp lining or poor insulation around the opening. These are the surprises a survey reduces but cannot always remove, which is why a good quote states how any such extra will be handled before you sign.
Cheap, mid and expensive: what you get
A low quote usually means a standard-size window in a straightforward roof, a basic glazing option, and no extras. It is a fair price for a simple job and there is nothing wrong with it as long as the flashing, underlay collar and insulation collar are all included. A mid-range quote has a larger window, better glazing, a lined opening finished to a decorated standard and some scaffold. A high quote covers electric operation, a bespoke finish, a conservation-style unit, a bank of windows with a combined flashing, or a new opening on a tall house. The worth of each is in how it matches your need. A bedroom window you will open every day deserves good hardware, and a window over a landing needs only light.
There is also the cost of getting it wrong. A window fitted with the wrong flashing or without an underlay collar can leak within a few seasons, and the repair will cost more than the saving. Our guide to leaking roof windows shows how often it is the fitting, not the glass, at fault. A price that is much lower than the rest may leave out the details that keep water out.
Paying for it
Windows are usually paid for in stages: a deposit to order the unit, which is made to size or held in stock, and the balance on completion once you have checked the work. We prefer to agree the stages in writing with the quote, so there is no argument later. Be cautious about any firm that asks for the whole sum up front, and about cash-only deals that come with no paperwork, because you will want the written guarantee and any building control certificate when you come to sell. If you are financing the work as part of a larger home improvement, tell us early, as the lender may want a breakdown of the costs.
How to compare quotes
Ask each firm to quote the same specification: the make and model, the size, the glazing, the flashing kit, the structural work and the finish. Check that scaffold, waste, building control and decorating are either included or clearly excluded. Ask what guarantee covers the installation, and what it covers in writing. Ours is a 10-year workmanship guarantee, put in writing. Be sceptical of a price given over the phone with no survey. Our guide to roof window types helps you decide on the specification first, so the quotes are comparable.
When you want a number for your own roof, ring 01256 213956 to book a survey, or see our roof windows page for everything we fit and repair.
