Answered · Skylight & Rooflight Installation & Replacement Chelmsford

Can you replace a rooflight from inside the room?

The short answer

Almost never, and the reason is the covering rather than the glass. A rooflight is weathered by tiles, slates or a membrane that lap over the outside of the frame, and every one of those laps is formed from above. Taking a unit out from below means leaving the weathering intact around a hole, which is not physically possible on any of the systems used on British roofs.

There is a short list of genuine exceptions and a longer list of parts of the job that really are done from inside. This page sets out which is which, and what that means for the access on your particular roof. It is part of the wider skylight replacement work Sunspire carries out across Chelmsford and the surrounding thirty miles.

Why the work happens from above

Look at the order in which a rooflight was built and the answer is obvious. On a pitched slope the underlay is dressed into the frame, the flashing kit sits over the frame, and the tiles or slates are then laid over the flashing. On a flat roof the membrane runs up the kerb and over its top edge, and the unit lands on top of that.

Everything that keeps water out is therefore outside and above the frame, and it was installed after the frame went in. To get the unit out, that sequence runs backwards: covering off, flashing off, fixings released, unit lifted clear. None of those steps has an inside equivalent.

The rooflights that come out downwards

One family is different. A fixed flat rooflight bolted through a base frame onto a kerb, with the covering dressed up the kerb and terminated under the frame, can occasionally be released and dropped through the opening where the deck build-up allows it and the unit is small enough to handle in a room.

That is a lifting decision rather than a weathering one, and it only helps if the covering above still has to be dressed back and made good afterwards, which it does. So even here the roof is worked on. The internal drop simply solves the problem of getting a heavy unit down a scaffold rather than lifting it over a parapet.

The parts of the job that happen from below

A useful share of a replacement day happens in the room, and it is the part that decides how the finished job looks.

Protecting the room, taping the ceiling opening and building a dust screen before anything is cut.
Releasing the internal lining around the old frame and setting it aside.
Checking the trimmers by hand once the frame is out and the opening is visible.
Setting and packing the new frame square, which is done with somebody below sighting the reveal line.
Reforming the lining, taping, skimming and finishing the reveal.

On a straightforward roof window swap that is close to half the labour, which is why a job with no internal access booked runs into trouble on the day.

Sun tunnels, and the part done from a loft

A sun tunnel is the closest thing to an inside job in this trade, and only in the middle. The collector on the roof goes in from outside with a flashing exactly like a roof window, and the diffuser is cut into the ceiling from the room below.

The tube between them is assembled from within the loft, threaded past purlins and truss webs by somebody kneeling on boards with a torch. On a bungalow or a house with a generous loft, that is a comfortable morning. On a shallow trussed roof over a landing, it is the part of the job that takes the time.

Blinds, glass and the fittings that stay indoors

Several things people ask about really do happen without anybody going on the roof. An internal blind clipped into the side channels of an existing frame is fitted from a stepladder. A control rod, a handle or a hinge on a centre pivot unit is changed from inside because the sash rotates fully and locks in the reversed position.

On some roof window designs the sealed unit itself can be changed with the sash rotated inwards, which is a different question from replacing the whole rooflight and is covered on our page about changing only the glass. Whether that route is available depends on the model and the age of the frame.

What the access actually needs to be

Since the work happens from outside, the question becomes what gets somebody safely onto that part of the roof, and the answer varies enormously across the county’s housing stock.

A ground floor rear extension flat roof reached off a garden is usually a tower. A pitched slope at first floor is edge protection and a roof ladder or a scaffold, and the choice depends on pitch, the state of the covering and how long the opening is up there. A third floor slope over a narrow side return in a Chelmsford terrace is scaffold, no argument. Our page on working without scaffold goes through where each option is appropriate.

Protecting the room while the roof is open

A rooflight opening is a hole from a dusty environment straight into a finished room, and the dust that comes down is fifty years of roof void: mortar snots, bat droppings, felt fibres and mineral chippings.

The standard is a taped polythene screen across the opening from below, floor coverings out to two metres, and furniture moved or sheeted. The screen also catches anything dropped, which is the more important function. On a job where the ceiling is being reformed anyway, the screen goes at ceiling level and the whole reveal comes down inside it.

Rooms where the internal side sets the programme

Occasionally the room below decides more about the day than the roof does. A bathroom with a suite directly under the opening, a kitchen with a run of units against the wall, or a loft bedroom with a fitted wardrobe under the sill all constrain where a working platform can stand inside.

That is worth flagging at survey rather than on the morning, because the fix is usually simple. Half an hour of moving furniture the evening before turns an awkward day into an ordinary one, and it costs nothing.

What the survey settles about access

Access is the largest single variable between a range by email and a fixed written price, so the survey spends real time on it. It establishes what the roof is, how it is reached, whether a tower can stand on the ground available, where materials will be laid out and where the old unit and its glass will go.

It also settles the internal half: which room, what is under the opening, what protection is needed and whether the ceiling is where the drawing says it is. Between those two lists there is very little left to be surprised by, which is the entire point of surveying before quoting rather than after.

Tell us about your roof

We start with the building, the covering and the slope. Then we tell you what will suit it, and what it will cost, as a fixed written number.

Surveyed before it is priced
10-year workmanship guarantee
Building Control notification handled
New installations and replacements