How long does a rooflight installation take?
A day for a straightforward one. The wait beforehand is manufacturing.
Part of our Replacing a Failed or Misted Rooflight guide
The fitting is short. The lead time before it is usually the longer part.
On site
Like for like replacement, same size: one day.
Replacement with the opening adapted: one to two days.
New opening in a pitched roof: two to three days, including forming the opening, structure, fitting, and the internal reveal.
New opening in a flat roof: two to three days, including building the kerb and making the covering good.
Roof lantern onto an existing kerb: one to two days.
Sun tunnel: half a day to a day.
Lead times before that
Stock size roof windows: often days.
Made to measure rooflights: two to four weeks.
Roof lanterns: three to five weeks.
On flat roof work the unit is ordered from a measured kerb rather than a drawing, so the sequence is survey, build or measure kerb, order, wait, fit.
Where a steel is involved
Add the engineer’s design time before anything is ordered, because the steel position sets the kerb position and the kerb sets the unit size.
What can extend it
Soft timber found when the old unit comes out, which is flagged as a possibility at quotation. And weather, where we reschedule rather than work through it badly.
Internal finishing
Plastering and decorating the reveal is separate and usually happens a few days later once everything has settled.
Typical durations
A like for like replacement into a sound opening: one day. Strip out, frame in, weathering, insulation collar, lining made good, handover.
Two or three replacements in one visit: two to three days. Not three times one day, because the access is shared and the second and third go faster than the first.
A new opening in a pitched roof: three to four days. The extra time is structure and making good rather than the window itself. Where plastering is involved there is also drying time before decoration.
A flat roof rooflight where the kerb already exists and is sound: one to two days. Where a kerb has to be formed and insulated, two to three.
A roof lantern on an existing extension: usually a week, including the structural work to trim the opening.
A sun tunnel: half a day for a short run in a bungalow, a full day for a longer route through a loft and a first floor void.
What actually delays a job
Almost never the fitting. Three things lengthen a programme and all of them happen before anybody arrives.
Lead time on the unit. Stock sizes are quick. Made to measure units, conservation rooflights and lanterns are manufactured to your dimensions and run to several weeks, sometimes longer for a large or unusual configuration.
Permission. Where planning permission or listed building consent is needed, that is measured in months rather than weeks. It comes first, before the order, because ordering a unit that may not be consented is how money gets wasted.
Structural input. Where a trussed roof means a designed trimmer, the engineer’s drawing has to come before the order rather than alongside it.
The sensible sequence is survey, permission where needed, structural check where needed, order, then book the fitting to the delivery date. Booking the fitting first and hoping the unit arrives is how jobs slip.
Weather
We work through the winter, and the rule is that an opening is never left uncovered overnight and a strip out does not start if the forecast will not allow the roof to be closed the same day.
In this part of the country that occasionally costs a day. It has never cost a customer a ceiling, and we would rather move a date than take a risk with an open roof.
Disruption inside
Most of the work is inside rather than on the roof, which surprises people. Floors are covered, furniture moved or sheeted, and a dust barrier goes at the door before anything else happens, because the making good is where the mess comes from.
Booking with a builder
Where the rooflight is part of a larger project, tell us the builder’s programme early. The kerb detail on an extension and the capped cable to a rooflight position in a loft conversion both need to happen at a particular moment, and both cost almost nothing then and a great deal afterwards.
Ask us
Send a photograph of the roof and one looking up inside the loft and we will give you a realistic programme along with the price, including the lead time on the unit rather than an optimistic guess.
What we confirm before booking
A confirmed delivery date for the unit rather than an estimate, any structural design where a trimmer is needed, and any consent where one applies. We book the fitting to those rather than to a hopeful date, because a date you can plan around is worth more than one that moves twice.
One last point
Drying time is not working time. Where making good involves plastering, the room is finished but not decorated at the end of the job, and in a cold house that gap is longer. We say so at booking rather than leaving it as a surprise.
The visit itself
A single unit into an existing pitched roof, accessible, with sound timber: most of a day for a competent pair. That covers stripping the covering back, forming and trimming the opening, setting the unit, the insulation collar, the underlay collar, the flashing, and reinstating the covering.
A flat roof unit onto a new kerb is similar once the kerb exists, and considerably longer if the kerb has to be built and the waterproofing formed.
Cutting a rafter, or a change of size, adds time. Timber repair adds time and cannot be scoped until the old unit is out.
The parts either side
Access goes up before and comes down after, which adds days at each end even though nobody is on the roof.
Plastering follows the fitting, and fresh plaster has to dry before decoration. The room is usable but not finished on the day.
And the lead time before any of it: days for a stock size, weeks for made to measure, months where consent is needed.
More on Replacing a Failed or Misted Rooflight
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