Question answered
How long does it take to fit a roof window?
The short answer
A roof window swapped for one of the same size is the quickest job, because the opening is already framed. A new opening takes longer: the covering is stripped, rafters are cut and trimmed, the frame is flashed, and the room is lined and finished inside. Weather decides when the roof can be open, and scaffold notice can set the start date. We give the plan after the survey, with the written quote.
How long a roof window takes depends mostly on whether the opening already exists. Swapping like for like is a short job, a new opening in a tiled or slate roof has more stages, and the weather has the final say.
Swapping one window for another
When an old roof window comes out and a new one of the same size goes in, the structural work has already been done. The opening is framed, the rafters are trimmed, and the covering is cut to suit. The job is to remove the old sash and frame, check the timbers and battens around it, fit the new frame, and renew the flashing, the metal or lead sections that seal it to the roof.
Even then, it is not just a quick swap. Old flashing is often tied into the slates or tiles in ways that only show when it comes away, and the lining inside may need making good once the new frame is in. Our answer on replacing an old roof window covers what to expect.
A like-for-like swap can usually be planned around a single dry spell. So we want to inspect the existing window, and the loft behind it, before giving any timing.
A new opening has more stages
Cutting a new opening takes the job through several stages, and each one depends on the last. The covering is stripped around the position, the battens are cut, and any rafter in the way is cut and the load carried round by trimmers. The frame is fixed to the timbers, the flashing kit is layered in step with each course of tile or slate, and the covering is then made good.
Inside, the reveal is lined, insulation is fitted to close the gap around the frame, and plastering and decorating follow. These finishing trades come on separate visits, and fresh plaster has to dry out before any paint goes on.
A new opening in a loft room may also need building control involvement where the structure is altered, because the Planning Portal lists structural alterations among the things that need approval. If we handle the notification, that is a lead time to allow for before the first day on site.
Weather decides when the roof can be open
A roof window job is the one time a section of your roof is deliberately opened up, so the forecast matters more than the calendar. Work is planned so that the opening is made weathertight before the day ends, either by the finished window or a temporary covering fixed over it.
On this coast, a settled-looking day can change fast, and sea gales are not the time to have a hole in a slope. A postponed start costs less than a flashing done in a hurry. Expect the programme to be agreed as a window of days and confirmed nearer the time, not a promise made weeks ahead.
The same caution applies to the room below. Furniture, bedding and floors under the opening should be covered or moved, and a sheet is usually hung inside the loft at the position of the new window before anything is removed.
Access and scaffolding can set the start date
Where the job needs a scaffold on the roadside, the scaffold firm has to apply for a highway licence under section 169 of the Highways Act 1980. West Sussex County Council states 10 working days as the least notice it needs between application and the day the scaffold is erected. That wait has nothing to do with how fast the window itself is fitted.
Not every job needs scaffold. Some low roofs can be worked from a hooked roof ladder, and some of the work is done mostly from inside, as we explain in our answer on fitting a roof window from inside. Whether a given roof allows that is decided at the survey, on the day, from the real access and the height of the eaves.
Inside the city boundary, Brighton & Hove City Council licenses scaffolds itself, on a different notice period from the county.
What affects the timetable, and what to ask
The things that move the timetable are the opening (new or existing), the covering (slate is slower than tile), the pitch, the access, whether the window is electric, and the finishing inside. See also the points on minimum pitch, flashing kits and walk-on rooflights, which have their own fitting needs.
Ask any roofer how many visits the job needs, who does the lining and plastering, what happens if rain is forecast on the day, and whether the quote includes scaffold and VAT. Each of those gets answered during our visit, and photographs arrive with the written quote. The neighbouring pages to read are our skylights and roof windows page.
One more practical point is the state of the loft. Boxes, stored furniture and wiring near the window position slow the job, so clearing a path and a working space beforehand saves time on the day. Tell us about any water tank, cable run or loft boarding near the planned position, since moving those adds a visit.
Roof window timing: two more questions
Can a roof window be fitted in the rain?
It can be started on a dry day and made weathertight before the rain comes, but the roof is not opened up in wet weather. If the forecast turns, the opening is covered and the job waits. That is a normal part of this work, not a sign something has gone wrong.
How soon can I use the room after the window is in?
Usually once the window is fitted and the reveal is lined, but plaster and paint need time to dry. A like-for-like swap can leave the room usable straight away, a new opening takes longer, and we explain which applies when we survey.
Tell us about your roof
Describe what is happening and we will call you back to arrange a visit.
- Photographs of what we find
- A written quote with one total price
- Or call 01903 299063
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