How long does it take to fit a VELUX window?

What the fitting day covers

On the day, the work is a sequence. The roof covering around the opening is lifted, the old window or the timber frame is dealt with, the new VELUX window is set into place and fixed, and the flashing that sheds water around it is laid into the tiles or slates. Then the weather side is closed up, so that the roof is sound again before anyone leaves the site.

A window going into an opening that already exists, or into one the builder has framed to our written sizes, is the quick case. Everything the window needs is in place and the work is mostly fixing and weathering. That is why the brief version of the answer is a day or less for one unit. The word usually matters: it describes a straightforward roof with clear access, and it is the quote that fixes the time for your address.

The lining is the part that waits. The inner lining kit and any insulation around the frame can sometimes be fitted on the same visit, but the plastered finish to the reveals comes later, once the window is in and the plasterer is booked.

Cutting a new opening takes longer

If there is no opening yet, the job begins with the structure. In a traditional cut roof, one or two rafters are trimmed and new timbers, usually called trimmers, take the load round the opening. That has to be done accurately before the window can be set, and it is why a new opening is a bigger day than a swap.

Trussed roofs are a different matter. A truss cannot just be cut, so the window either fits between the existing members or an engineer designs the change first. We check this on the survey, because it decides whether the work is a day on the roof or something to plan ahead.

Where the roof is being built new, such as an extension or a loft conversion, the carpenter can frame the opening to the size we have sent in writing. The window then goes in as part of the programme rather than as an interruption to it. Our page on VELUX sizes and codes explains how the width and height are read, which is what the builder needs to frame to.

More than one window

Two or three windows in one roof are not simply the same job twice, but they are close to it. The setting up, the access and the clearing away happen once, and each window then takes its own run of lifting, fixing and flashing. The total grows with the number of units, though not in a straight line.

Windows that are combined side by side, or stacked one above another, need more care than separate ones. They share flashing and have to line up, so they take longer than the same number fitted apart. The quote says whether the units are separate or combined and what that does to the time.

It also helps to settle the sizes before the day. The windows arrive together, so a wrong code is found on the roof rather than at the order stage. That is the reason every code is confirmed in writing with the homeowner and the builder first.

What changes the time on the day

• Roof covering. Plain tiles and slate take longer to lift and relay than large concrete tiles, because there are more pieces to handle and fix.
• Access. A bungalow can be reached with a tower. A tall house may need scaffolding, which is put up before the fitting day.
• Pitch and condition. A shallow pitch may call for extra underlay detail, and timbers that have decayed around an old opening have to be made good first.
• Weather. Wind and rain can hold the work, since the roof must not be left open. Moving a day is better than exposing your loft.
• Blinds or electric operation. These need cable runs or fixings planned before the lining goes in.

Most of these are visible from the survey. The ones that are not are the reason we ask the builder what lies under the covering wherever they can tell us.

Fitting inside a larger build

If the roof belongs to a project with other trades, the length of the fitting day is only part of the picture. What matters more is where it falls in the sequence. The roofer lays the covering up to the opening, we set the window, and the roofer closes the flashing. The electrician then runs any cables for blinds or lighting, and the plasterer finishes the reveals.

That order stops the work being done twice. The window is ordered to land on site as the roof reaches that stage, and once the delivery date is confirmed both the homeowner and the builder are told, so the roof does not stand open waiting for glass. How long the windows take to arrive comes from the maker, and the quote states it.

If you are replacing a window rather than adding one, our guide to replacing an old VELUX covers what changes. If you want a blind at the same time, choosing blinds at fitting explains why it is easier before the lining goes on.

Getting a time you can plan around

Book a survey and the roof, its pitch, the covering and the access are all inspected. The written quote that follows states the window, the expected fitting time and what the builder must provide. For the full picture of what we install, see our VELUX windows page, and for what moves the price see what the fitting cost depends on.

Should the work be part of a bigger programme, tell us when the roof is expected to be finished. We place the order by counting back from that day, so the fitting lands when the roof is ready.

Related questions

Do I have to stay at home during the fitting?

Someone needs to give access to the loft or room below at the start and end of the day, and to agree where dust sheets and the ladder go. Staying in the room is not necessary. If the house is empty during a build, the builder can arrange access with us.