Roof window installation cost: fitting, electric models and scaffold

MyBuilder's guide gives installation at £350 to £600 for standard jobs, and says that figure includes both labour and fitting. Beside it, the guide puts a standard centre-pivot unit at £305 and electric models at £420 to £590, and gives approximately £500 for scaffolding. Read together, they describe a plain replacement or a straightforward new opening on a normal pitched roof, not a complicated one.

These numbers map the territory; they do not price your roof. Add the parts that apply to you and a small job lands at a very different total from a large or awkward one. When our quote reaches you it is one total covering everything, with a plain explanation of what shaped it.

Is the window price part of the fitting price?

The guide describes its fitting range as covering labour and fitting, and lists the window unit separately, so treat the two as distinct parts that a quote may or may not combine. When a total arrives, ask what it includes: the unit, the flashing kit, the lining inside and the clearing away afterwards are all things that can sit inside one figure or outside another.

The published ranges show electric models starting well above the standard centre-pivot price, at £420 to £590 against £305. What the extra pays for is a motor and the means of controlling it: a remote or wall control, sometimes a rain sensor, and a power supply to the frame. Some electric windows are solar-powered, which avoids running a cable but means the unit depends on the light that reaches it.

The motor matters most where the window is out of reach, such as above a stairwell, a high landing or a double-height space. A manual window there needs a pole, and a pole is a nuisance to use day after day. Over a bed, within arm's reach, a manual window usually does the job and costs less to buy and less to wire.

Does an electric window need an electrician?

If a mains cable is involved, the connection is electrical work, and the wiring route from the nearest circuit to the frame becomes part of the job. The route can be short in a loft with power close by, or fiddly where the ceiling below is already finished and the cable has to be chased in or hidden behind new boarding. Our answer on whether electric roof windows are worth it goes into that decision.

A middle course exists for a window that is only slightly out of reach: a manual unit with a control bar, which keeps the price near the standard range. We look at reach and ceiling height during the survey so the choice rests on the actual room and ceiling, and not on a catalogue picture.

On most pitched roofs it is a real cost. MyBuilder's roof window guide puts scaffolding for the job at approximately £500. Its wider scaffolding guide quotes around £850 to £1,200 for the standard setup on a two-storey house, with weekly domestic hire at £300 to £900, and Checkatrade's roof replacement guide gives £700 to £1,300 for scaffold on a re-roof. A single window sits at the low end because a tower or a short run of scaffold may be enough, while a full elevation costs more.

Those are three sources with three scopes, so do not mix them up. The window-specific figure is the nearest guide to a one-window job. The larger numbers apply to scaffold across a whole elevation or a full re-roof, and they would overstate a single opening.

Can the scaffold be shared with other work?

It can, and that is one of the few genuine ways to lower the cost of each job. If a window, some chimney repointing and a gutter repair are all due, a single scaffold visit can serve all three. A tower that goes up for a window and comes down again is poor value if the guttering will need access within the year. We say at survey when a second job could use the same access, and what it would involve.

Size comes first. A wide window costs more than a narrow one, a better glazing spec costs more again, and both feed through to the labour of lifting the unit onto the roof and fixing it. The next factor is access: a low rear roof reached from a flat garden is a different job from a third-floor loft above a terrace with a shared yard.

The covering matters because it decides the flashing kit. Slate, plain tile and deep interlocking tile each need a different one, and our guide to roof window flashing kits sets out the options. Swapping a unit within its existing opening is usually simpler than cutting a fresh one, where rafters need trimming and the ceiling below needs lining and plastering. Height also counts, since every extra storey makes the scaffold taller and the lift to the roof longer.

Which glazing options raise the cost?

Laminated safety glass, acoustic panes that dull the sound of rain, solar-control coatings for south-facing rooms and larger sizes all add to the unit price. They earn their place in the right room: a bedroom on a busy road is a different case from a landing at the back of the house. In a quiet room a lower-spec pane is often enough.

Do several windows at once save money?

They can, because scaffold, delivery and set-up are shared between them. How much depends on the roof and the layout. Two windows on one slope are cheaper to access than two on opposite sides of a hipped roof, and the survey is where that difference becomes a figure.

A replacement into an existing opening is the cheaper job in most cases. The old unit and its flashing come out, the new window and a new flashing kit go in, and the lining inside is touched up. Most of the cost is the window, the kit, a day or less of labour and the access.

A new opening adds a chain of work. The covering is stripped back, the opening is marked out from inside, rafters are cut and trimmed with new timber, the window is installed and flashed, and the ceiling is lined and finished below. It may be notifiable under the Building Regulations, and our page on roof window building regulations sets out when. It may also need planning permission, or it may not; that depends on where the window goes, and the guide to roof window planning permission works through it.

Is the internal finish included in a roof window price?

Not always. The plasterboard, skim and paint around the window are sometimes the homeowner's decorator's job and sometimes the roofer's. A good quote states which, and asking early avoids a bare plaster surround in a finished bedroom.

If you are wondering whether a window is the right answer at all, a sun tunnel is a different way to bring light into a landing or bathroom, and its own guide explains where it fits.

Quotes from different roofers often look far apart when their scope is the only real difference. One includes scaffold and VAT; another leaves both for later. One supplies a flashing kit and a lining; another prices the window and nothing else. Before you compare totals, compare what each total covers.

Ask which window is quoted, by model and size. Ask which flashing kit suits your covering. Ask if the total takes in scaffold and VAT, who clears the site afterwards, and which guarantee applies and for how many years. If the answer to any of those is vague, the price is not yet comparable with another.

What does a Skyline quote look like?

We start by photographing your roof, then send a written quote as one total. Our prices are good and fair. The job we propose is the smallest one that cures the fault, and for a roof window that can mean a straight swap and no bigger opening. A written 10-year guarantee covers the workmanship, and we tidy the site and carry off the waste.

Where do the guides on this site fit in?

Treat the ranges here as a rough guide, and let the survey of your own roof set the real number. If you are choosing between a window and a skylight in the wider sense, the answer on roof window or skylight clears up the terms, and our skylights and roof windows page lists every guide in this set.