Can a rooflight be moved to a different part of the roof?
Yes, and it is best understood as two separate pieces of work happening on the same visit. A new opening is formed, trimmed and weathered in the new position, exactly as it would be for a first installation. The old opening is closed: the frame comes out, the structure is made continuous again, the underlay is made good, and the covering is laid back across it so the slope reads as though nothing was ever there.
Closing the old opening is the half people underestimate. It carries most of the fiddly work, all of the tile matching, and the risk that the finished roof shows a rectangle in a slightly different colour for the next decade. This page sets out what each half involves and how the two fit together.
Yes, and it is two jobs rather than one
Pricing and programme both follow from that. The new position is a standard installation with its own trimming, its own flashing kit and its own internal lining. The old position is a separate operation with its own carpentry, its own membrane work and its own tiling.
Neither half subsidises the other. The only genuine saving in doing both together is the access arrangement, which is shared, and on a two storey slope that is a real saving. Beyond that, expect the work to reflect two openings rather than one.
Why a unit ends up in the wrong place
The reasons are consistent and none of them are exotic. A loft is converted and the window that lit a storage space is now above a stairwell rather than a bed. An internal wall moves and the light lands in the wrong room. A bathroom is reconfigured and the window sits directly over a shower where privacy and moisture both become issues.
The other common driver is orientation. A unit on a slope that turns out to overheat in July, or one on a plane so shaded by a neighbouring roof that it never quite delivers, is sometimes better moved than re-glazed. Whether that is worth doing is a daylight question first and a building question second.
Closing the old opening properly
The frame and the flashing come out and go, because a pressed kit that has been dressed into a roof does not come out reusable. What is left is a hole in the rafters with trimmers around it and a break in the underlay.
Rafters are made continuous with new timber of the same section, spliced to the existing members with structural screws or bolts over a generous overlap rather than butted and nailed. Where the original installer doubled the flanking rafters, that doubling stays: it does no harm and taking it out achieves nothing. Battens are then run across at the existing gauge so the covering has something continuous to hang on.
Making the covering match over a filled opening
This is the part that decides whether the work reads as invisible or as an obvious rectangle. Tiles that have been on a roof for fifty years have weathered, and new tiles of the same pattern arrive bright.
The answer is to move tiles rather than to buy them. Sound weathered tiles are taken from a less visible slope, a rear elevation or the section below a parapet, and used to fill the old opening. New tiles then go into the place the old ones came from, where they are out of the eye line and will weather down over a few winters. On a handmade clay roof in Thaxted or Coggeshall that sorting is most of the skill in the job.
Putting the underlay back as a continuous plane
The membrane around an old opening was cut, dressed and turned up against the frame, so it cannot simply be pushed flat. New underlay is let in across the closed opening and lapped correctly with what remains: over the sheet below, under the sheet above, so water travels on the top face all the way to the eaves.
Where the existing membrane is old bitumen felt that has gone brittle, and on Essex roofs from before the seventies it usually has, it is cut back to sound material before the new piece is lapped in. Lapping a new sheet onto a crumbling one achieves nothing, and the joint is the exact place water would arrive.
The ceiling below, and what it needs
Inside, the old reveal comes out and the ceiling is made continuous. Insulation is let back in between and below the rafters to the same depth as the surrounding roof, the vapour control layer is taped across the gap to the existing membrane, and the plasterboard is boarded, taped and skimmed.
Two things are worth planning for. A newly filled area of plaster in an old ceiling almost never disappears under a coat of emulsion, so the honest expectation is that the whole ceiling gets a skim or the room gets decorated. And an old artexed or lath and plaster ceiling behaves unpredictably once you start cutting into it, which is a conversation better had at survey than on the second morning.
Reusing the old unit, or ordering a new one
The frame can be reused if it is sound, and the test is honest rather than sentimental. Look for misting between the panes, a timber frame gone grey and fibrous at the sill, a chalky brittle finish on the external face, and whether the sash still compresses its gasket evenly all round when closed.
A sealed unit has a working life of roughly twenty to twenty five years, so a window being moved after fifteen is a candidate for reuse and one being moved after thirty is not. The flashing kit is renewed either way. Where the unit is being changed at the same time, it is a good moment to upgrade the glazing, because the labour is already committed. What transfers and what does not is set out on the skylight replacement page.
Regulations when a unit relocates
Forming a new opening is notifiable work, and it engages the same parts as any new installation: Part A because structure is altered, Part L because a new glazed element is going into a roof, and Part B where the room is a habitable loft room needing an escape opening. Sunspire handles the notification as part of the job.
Two points catch people out. If the original window was the escape window for a loft room, the new one has to meet the same clear opening area and height above floor level, which rules out a centre pivot in that position. And in a conservation area, moving a window is a new position on a roof plane rather than a like for like swap, so the planning position is checked before anything is ordered.
Doing both openings in one visit
The sequence matters because the roof is open in two places. In practice the new opening is formed, trimmed, framed and weathered first, so there is a finished, watertight unit in the roof before the old one is disturbed. Then the old frame comes out and the closing work runs from carpentry through membrane to covering.
On a straightforward pitched slope the whole thing runs to two or three days externally, with the internal finishing following on. The roof is closed and watertight at the end of every working day, in both positions, whatever the weather is doing. The detail of how a new opening is formed and weathered sits on the roof window installation page.
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