How Long Does a Commercial Rooflight Programme Take?
A straightforward in-plane rooflight replacement runs at roughly a bay a day for a two-team operation once mobilised, so a typical warehouse of 40 to 80 rooflight sheets is often a one to two week job, plus a four to eight week lead time on materials beforehand. Access equipment, weather and restricted working windows all extend that, and a discontinued profile adds to the lead time rather than the install.
This answer sits under our commercial skylight installation service. The honest version is that duration is set by your building, not by an average, so the figures below are for planning and the survey gives the real programme.
Indicative durations
| Scope | Material lead time | Time on site |
|---|---|---|
| Small roof, up to 20 in-plane sheets | 4 to 6 weeks | 2 to 5 days |
| Typical warehouse, 40 to 80 sheets | 4 to 8 weeks | 1 to 2 weeks |
| Large roof, 150 sheets plus, single phase | 6 to 8 weeks | 3 to 5 weeks |
| Barrel vault or continuous run | 8 to 12 weeks | Depends on run length and kerb work |
| AOV smoke vent units | 8 to 12 weeks | Adds commissioning time per unit |
Time on site is for reasonable access, normal hours and standard profiles. The variables below move all of these.
What extends the programme
Access equipment
How the roof is reached often affects the timescale more than the sheet count. A low roof with a safe internal route lets work start quickly. A high roof needing a mobile elevating work platform or a crane adds set-up and repositioning time, and repositioning access around a large building can add days across a programme.
Weather
Because we open only what we can close and make weather-tight the same day, a wet or windy spell slows the work rather than risking the building below. This is a feature, not a fault: it is what keeps your stock dry. A settled week moves quickly, a wet one does not, and the programme carries a sensible weather contingency rather than a best-case promise.
Restricted working windows
Out-of-hours and shutdown working changes the arithmetic. Night shifts are shorter productive windows than full days, so the same roof takes more calendar time even though the total work is the same. A school or public building worked only in holidays is paced by the holiday calendar. These windows are planned from the start, and our replacing rooflights in an occupied building page covers how they are worked.
Profile availability
A discontinued profile needing a moulded-to-match sheet extends the lead time, not the install. Tooling and a minimum order add weeks before material arrives. The time on the roof is unchanged once it does. This is common on older Ipswich stock and it is established at survey.
Lead time and site time are separate. Most of the elapsed time on a rooflight job is the material lead time before anyone is on the roof, not the install. Nothing on the roof is opened before the material is on site, so a four to eight week lead time on a one to two week install is normal. Planning around the lead time, rather than the site time, is what keeps a programme realistic.
What it means around Ipswich
Distribution and logistics sites around the port and the A14 corridor frequently run late, so night working is often the only clear window, which lengthens the calendar programme even where the work is straightforward. On the coastal belt near Felixstowe and Harwich, weather exposure means a larger contingency in the wetter months. Inland, around Colchester and the Suffolk towns, daytime working on accessible roofs tends to run closest to the indicative figures.
How long to replace a typical warehouse roof of rooflights?
For a typical warehouse of 40 to 80 in-plane sheets, plan on a four to eight week material lead time and one to two weeks on site, for reasonable access and normal hours. Night working, difficult access, a discontinued profile or a wet spell all extend it. The survey converts your roof into a firm programme.
Does night working take longer than day working?
In calendar terms usually yes, because a night shift is a shorter productive window than a full day, so the same total work spreads over more nights. It also costs more, for the labour premium and task lighting. Where a building can only be worked out of hours it is planned that way from the start, with both the timescale and the cost set out openly.
Get a real programme for your roof
The figures here are for planning. A survey turns them into a dated programme built from your building’s access, your operating pattern and the actual profile on the roof.
Request a survey. Read across to how a phased programme is planned, what warehouse rooflight replacement costs, and the occupied building method.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.