Can an Electric Rooflight Be Fitted to a Pitched Roof?

A flat rooflight and a pitched roof window solve the same problem in different ways, and the difference is entirely in the frame, not in what makes the glass move.

A flat rooflight sits proud of the roof on a raised kerb, called an upstand, with falls built into the deck around it so rain sheds away on every side. Our page on hinged or sliding flat rooflights covers how that upstand carries the hinge or the sliding track. A roof window on a pitch has no upstand at all: the frame sits within the plane of the roof itself, following the tile or slate line, with a flashing kit built for that specific pitch so water simply runs over the top of it and down the slope. How electric opening rooflights work sets out the actuator and control unit both products share; nothing in that mechanism cares which frame it sits inside.

Fitting a roof window between rafters is mostly carpentry and flashing work, and the electric parts add relatively little to that once the opening is formed correctly.

The rafters either side are trimmed and lined to the size code of the window being fitted, a header and sill built in to carry the load the rafter section used to take, and insulation and a vapour layer taken right up to the frame so the opening performs as well as the roof around it. Onto that frame goes the pitch-specific flashing kit, sized to the roof covering, tiles or slates, and to the angle of the slope itself. The electric sash then goes in exactly as a manual one would, except that its chain or spindle actuator, wiring or solar cell, and a small run of cable or a battery pack, are fitted at the same time rather than added afterwards.

Building Control treats a roof window on a pitch the same way as any other rooflight: the work is notifiable, and we handle that notification and install to current Building Regulations, whichever roof shape the job involves.

A manual roof window works perfectly well on most pitched roofs within easy reach of a control rod, so the electric version tends to prove itself in a narrower set of rooms.

• High up a vaulted ceiling, where a control rod would need to be several metres long to reach a handle
• Over a stairwell, where standing underneath the window to open it by hand is awkward or means a ladder
• Set into a loft conversion roof that slopes away from the landing rather than sitting within arm's reach
• A bedroom or landing where night-time ventilation matters and a rain sensor closing the window unattended is worth having

Can an electric rooflight go in a loft conversion? goes through the reach problem in more detail for that particular room, and it is one of the clearest cases for choosing electric over manual on a pitch.

Nothing about being set into a slope rather than a flat kerb changes how the electric side of the job is specified.

Our guide to powering an electric rooflight: mains, solar or battery covers the choice between the three, and it holds whether the frame sits on a kerb or in a rafter run. The same is true of rain sensors and automatic closing, and, for a roof exposed to the flat, open horizon on the edge of Peterborough, of why a rooflight would need a wind sensor. A pitched roof window catches wind slightly differently to a flat rooflight, since it faces the weather at an angle rather than sitting level, but the sensor and the response it triggers are identical hardware either way. Controls, remotes and smart home links apply the same way too, so a household with both a flat rooflight over the kitchen and an electric roof window in the loft can usually run both from one system.

The sightline from below is where a pitched roof window and a flat rooflight actually diverge, and it is worth understanding before either is chosen.

A flat rooflight, fitted electric, has to carry a taller upstand and a hinge or track built into it, which is why opening rooflights and the view: frame depth when hinged exists as its own answer. A pitched roof window, by contrast, sits flush with the roof plane, so its frame reads as a picture set into a sloping ceiling rather than a box raised above a flat one. Looking up from a bed set square to the window, that flush setting can actually give a cleaner edge than an equivalent flat unit, though the sash still needs room to lift clear when it opens, and that clearance is exactly what a sightline sketch checks before the frame is ordered.

Peterborough gives three quite different pitched roofs to fit an electric window into, and the flashing kit is matched to whichever one it is.

Fletton brick terraces and semis across the older parts of the city carry ordinary tiled or slated pitches, the everyday case a standard flashing kit is built for. Loft conversions in the newer townships, Bretton, Orton and Werrington among them, more often bring a steeper roof pitch and a room that was never designed with a window in mind, which is where the reach argument for going electric tends to be strongest. Around Stamford and the Nene valley villages, Collyweston stone slate and limestone roofs call for a slim, flush conservation-style unit rather than a bulkier standard frame, and an electric version of that conservation unit is fitted with the same low-profile flashing, following the stone slate's own smaller module rather than a standard tile gauge.

A survey is what actually settles this, not a guess from the ground: the roof's pitch, its covering, the rafter spacing at the point a window would go, and how far the room's own eye position sits from where a control rod would need to reach.

From there we draw a sightline sketch for the room, showing the frame edge, the sash and how much sky is on view from where you actually sit or lie, whether the fitting turns out to be an electric roof window in a rafter or a flat rooflight on a kitchen extension roof. Our electric and opening rooflight installation page covers the full range this decision sits within, and the costs page sets out what affects the price of a rooflight or a roof window once the roof shape is confirmed. Every quote comes with the sightline sketch itself, drawn before the roof is cut.

Is an electric roof window on a pitch more disruptive to fit than a manual one?

Not really. The carpentry and flashing work is identical to a manual window of the same size; the electric version simply has a cable run, a solar cell or a battery pack added at the same stage, alongside the switch or remote it will be run from.

Can a manual roof window on a pitch be changed to electric later?

Not by adding a motor to the existing sash. Can an existing fixed rooflight be made to open? explains why the answer is usually a new sash built for electric operation, fitted into the same opening.

Does a steeper pitch change how far the window can open?

It can. How far does an electric rooflight open? covers typical opening strokes, and a steep pitch generally leaves the sash sitting more upright when open than the same window on a shallow slope.

Will an electric roof window on a pitch still close if the power fails?

Yes, in the same way any electric rooflight does. Will an electric rooflight close if the power goes off? sets out the battery backup and manual override that apply whichever roof shape the window sits in.