Can you replace rooflights on an occupied building?

Unit by unit, not roof by roof

The instinct with a run of twenty tired domes is to strip them and get the new ones in behind. On an occupied building that is the wrong shape of job. We take one unit out, form or make good the kerb, set the new unit, complete the flashing, and only then move to the next. At any moment there is one live opening on the roof and one protected area underneath it.

It is slower per unit and quicker overall, because nothing has to be watched, tented or guarded while it waits. It also means the disruption underneath travels across the building in a predictable line, so a department knows it has Tuesday and is clear by Wednesday.

Nothing stays open past the end of the day

An opening formed at nine is closed by four. If the weather turns, or a kerb is found to be in worse condition than the survey suggested, we close the opening down with the existing covering or a temporary weathering detail and come back to it. The alternative, a sheeted hole over an occupied floor overnight, is not something we offer on any building.

That rule shapes how much we start. Late in the afternoon, with a unit that is going to be awkward, the honest call is to leave it until the next morning rather than begin something that will still be open at six.

Getting men and materials up without crossing the floor

Access is the part that decides whether an occupied job is straightforward or painful. External access is always the aim: a stair tower or scaffold in a service yard, a mobile tower or a mast climber on a hard standing, or a tracked platform where the ground takes it. Where an external route is available, the operational side of the building never sees us.

Internal access is workable but costlier in disruption. It means protected routes, floor coverings, a lift booking or a stair kept clear, and a delivery window agreed with whoever runs the building. On retail and hospitality premises that usually pushes the work outside trading hours, which is covered on our page about working out of hours on a commercial building.

Weather dictates the order of the day

On an occupied building we make the weather call in the morning, not the week before. Steady rain means we do not open anything and we get on with kerb preparation, deliveries and setting out. High wind is the harder one: a large glazed unit on a slinging point or on a platform becomes unmanageable well below the wind speed that stops other roof work, and a unit that has to be abandoned mid-lift is a serious problem over a live floor.

We would rather lose a morning than open a roof over occupied space in the wrong conditions. It is one of the reasons a commercial programme carries float in it, and why we talk in ranges for dates rather than promising an exact finish for a run of units.

Inductions, permits and your site rules

Larger sites run permit systems, and we work inside them rather than around them. Roof access permits, hot works permits where another trade needs them, isolation permits where a rooflight sits near a smoke detector head or a sprinkler line, and site inductions before day one. We need the paperwork requirements at quotation stage, because a job that needs three permits a day runs at a different rate to one that does not.

The practical things matter as much as the forms. Where the keys are, who opens up, whether the alarm is off, where the welfare is, who to ring at seven in the morning when nobody is on the gate. A survey visit settles all of it in half an hour.

Noise, and where it lands in the working day

Rooflight replacement is not a quiet trade. Cutting back a covering, fixing a kerb down into a deck, and screwing a frame home all transmit into the space below, and on a metal deck the whole roof acts as a drum. In an office the complaint is not the noise itself but the noise arriving during a meeting nobody warned about.

So the noisy operations get scheduled. Fixing down happens in a block rather than in dribs across the day, and where a floor plate has a fixed pattern of meetings or a call area, we move the sequence to suit it. That costs nothing to arrange if it is discussed at survey.

Deliveries, waste and the ground-level footprint

A commercial unit arrives crated and it is not something two people carry across a car park. We need a delivery slot, a place to set the crate down that will not block a fire route or a loading bay, and a lifting arrangement. Old units go the other way, and a stripped GRP dome takes more space than people expect once it is off the roof.

Where a yard is tight, the answer is usually to phase the deliveries with the work so there is never more than a day’s material on the ground. That approach across a bigger roof is set out on our page about programme and phasing on a commercial roof.

What we need from you before the first unit comes out

A short list, and it is nearly always available. What is directly under each rooflight, including anything that cannot be moved. Whether the ceiling below is a suspended grid, a plasterboard soffit or open deck. Who owns the roof, if you are a tenant. Any period the building genuinely cannot be disturbed, such as an exam week, a stocktake or a trading peak. And the access constraints in the yard.

The protection arrangements below each opening are a subject of their own, and we set them out on our page about how we protect a working space below. Everything else is settled at survey.

How we price an occupied job

Two figures, as on every job. A range by email once we know the number of units, the sizes, the roof build-up and the access position. A fixed price after a survey, by which point we have stood on the roof, looked at the ceiling below and understood what your building can and cannot tolerate.

We install and replace rooflights only, which keeps the scope on a live building narrow and predictable. Our workmanship carries a ten-year guarantee, and we have been doing this for fifteen years across Oxford and twenty-five miles by road. Call 01865 704245 or email info@heritageskylightsoxford.co.uk.