Electric rooflights out of reach and why they suit

Measuring what counts as out of reach

Reach is not a feeling, it is a dimension. An adult of average height can comfortably operate a handle at about 2.0 metres from the floor and can just about manage 2.2 metres with a stretch. Above that, and certainly above 2.4 metres, the handle is not usable in any ordinary way.

The measurement that matters is to the operating point, not to the glass. On a top-hung roof window the handle is at the bottom edge of the sash, which may be a good deal lower than the middle of the pane. On a centre-pivot the handle is usually at the top of the sash, which is higher than the middle. Two units in the same wall of roof can therefore have operating points half a metre apart.

On a pitched slope, take the measurement vertically from the finished floor to the handle position with the sash shut. Do it during the survey, from the actual floor level rather than from a drawing, because floor build-ups move by 100mm or more between design and reality.

What a pole can genuinely manage, and where it stops

Manufacturer poles come in fixed and telescopic forms and typically reach somewhere between 1.0 and 3.0 metres, which sounds like it solves the problem. In use it is more limited than the specification suggests.

A pole works well up to about a metre above what an arm can reach. Beyond that, the angle between the pole and the sash gets awkward, the hook becomes hard to locate on the eye, and the weight of an extended telescopic pole held above the head becomes a two-handed operation carried out looking upwards.

There is also the storage problem. A three-metre pole has to live somewhere in the house, and wherever that is, it is not next to the window. The predictable outcome is that the vent gets opened in June and closed in September, which is not ventilation, it is a seasonal gesture.

The furniture problem: standing on things

When a unit is slightly out of reach and no pole is to hand, people improvise. A dining chair, a worktop, the edge of a bath, the arm of a sofa, a step stool on carpet. This is the part of the specification nobody writes down and everybody does.

It is worth naming plainly because it is the actual risk that a motor removes. A rooflight over a stairwell is the extreme case: there is no floor to stand on at all, only the stair, and anybody attempting to reach the window is doing so above a drop.

If the honest answer to “how would somebody open this” involves climbing on anything, the unit is out of reach and should be powered. That is a cheaper conclusion to reach at survey than after an accident.

Stairwell voids and the half-landing window

Stairwells produce the highest, most useful and most awkward rooflight positions in the average house. A window at the head of a two-storey stair might be five or six metres above the lowest tread, and it is the single best ventilation outlet the building has because it sits at the top of a continuous vertical shaft. That case is set out on opening rooflights for the stack effect.

Two things follow. The unit must be powered, because there is no realistic way to operate it by hand. And the control has to be somewhere sensible, which in a stairwell is usually at the bottom of the flight or on a landing, not adjacent to the window where nobody stands.

Access for later work is the other consideration. A stairwell rooflight cannot be reached with a domestic ladder, so any future attention means a tower or a tall access platform standing on stair treads. That is a reason to specify well the first time and to choose a unit with a service life that justifies the position.

Vaulted ceilings, where reach changes across the room

In a vaulted or partially vaulted ceiling, the height to the roof plane varies continuously across the room, so a rooflight can be within reach at one end of the vault and hopelessly high at the other. This is the situation where careful measurement pays for itself.

Roof pitch does the work. On a 40 degree slope, moving a unit one metre up the slope raises the operating point by around 640mm. Two units of the same size, a metre apart on the slope, can sit on either side of the reach threshold.

Where a room has more than one unit, do not assume they need the same specification. A low one can perfectly well be manual and a high one powered, and mixing them saves money without compromising anything. What we would avoid is a matched pair where one of them is a motorised unit that could have been opened by hand.

Double-height spaces and mezzanine returns

A double-height hall, a converted barn-style volume or an extension with a mezzanine gives heights of five metres and upwards, well beyond any pole. These positions almost always take powered units, and the interesting question becomes how many and how they are grouped.

Where a mezzanine or gallery overlooks the space, there is sometimes a temptation to put the control up there because it is nearer the window. Resist it. Put the control where people enter and use the room, at the level where somebody notices it is warm.

These volumes also stratify strongly. The air at the top of a five-metre space can be several degrees warmer than the air at head height, which means a high vent has genuine work to do and will be used often enough for the motor cycles to add up. That is an argument for specifying the better-built end of a range rather than the entry model.

Positions where there is nowhere to stand

Height is not the only kind of out of reach. A rooflight directly over a bath, over a shower enclosure, over a kitchen island with a hob in it, over a stair flight, or over a fixed run of built-in furniture is unreachable at any height, because there is no safe floor beneath it.

Bathrooms are the common case and the most important one, since a shower room is precisely where ventilation has to actually happen rather than merely be available. A window over a bath that needs somebody to stand in the bath to reach it will not get opened at the right times.

Kitchens follow the same logic. A rooflight above a run of units or above a hob is reachable only by leaning across a work surface, and in a room that generates steam and grease at high level, that vent needs to work every day.

Cleaning the inside face when you cannot touch it

People specify the opening mechanism and forget the glass. A high unit still gets dusty on the inside, and on a pitched slope it collects more than a vertical window does because it faces upwards into the room.

Some units help. Centre-pivot roof windows rotate through 180 degrees and lock, which brings the outside face indoors for cleaning, and on a powered unit the motor is disengaged for that operation. A top-hung unit does not do that, though many ranges offer a top-hung sash that can also be rotated for cleaning as a secondary mode.

Where the unit is genuinely at stairwell height, neither helps, because nobody can get to the sash to rotate it. Accept at the specification stage that cleaning will need a tower or a professional with the right access equipment, and factor it in rather than discovering it in year two.

Blinds at height are the second reach problem

A high rooflight admits high-angle summer sun into the top of a volume, and blinds are frequently wanted. A manual blind on a pole at four metres is worse than a manual window, because a blind is adjusted far more often than a window is opened.

The rule of thumb is simple: if the window is powered because of height, the blind should be powered too, and both should answer the same control. Specifying an electric opener and a corded blind on the same high unit is a half-finished job.

Doing the blind at the same time as the window is also considerably cheaper than adding it later, particularly at height where access is the expensive part. The later route is possible and is covered on can electric blinds be added later.

Why a rain sensor matters more the higher the unit

A rain sensor is useful on any powered rooflight. On a high one it moves from useful to close to essential, for a straightforward reason: nobody can shut the window quickly by hand when the weather turns.

With a low unit, somebody notices rain and closes it. With a stairwell unit five metres up, the only ways to close it are the control and the sensor. If the control is in another room and the household is out, the sensor is the whole defence.

It is still worth understanding the limits, which are set out on rain sensors and what they actually do. It reacts rather than predicts, and heavy wind-driven rain can get in during the closing cycle. Treat it as the backstop it is, not as permission to leave a high unit open when the house is empty.

Where the controls go when nobody can see the window

Control position is more important at height than at low level, because the user cannot simply look up and judge whether the sash is open. In a tall stairwell the window may not be visible at all from where the switch is.

Three things follow. Put a fixed wall control near the door of the room or at the foot of the stair, where a light switch would go, so operating it is on the way past. Choose a control that indicates state, so a user knows whether the unit is open without craning. And keep a handheld remote as an addition rather than the only means of control, so a flat battery does not lock the roof.

The wider control options are covered on remote controls, wall switches and smart home links. At height the priority is a wired, fixed, obvious control first, with the wireless conveniences layered on top.

Grouping several high units on one command

Where a tall space has three or four units, individual operation stops happening within a fortnight. Grouping them so a single press opens or closes the set is what makes high-level ventilation actually get used.

Most control systems handle this, and the useful arrangement is usually a group command plus individual control retained for the occasions when only one is wanted. How many a single control can carry depends on the system and the transformer capacity, which is covered on how many electric rooflights can one switch control.

Scheduling matters here too. A group of high units on a timed night purge does more for summer comfort than any amount of manual operation, precisely because it happens when nobody would have bothered.

Getting the cable there while access still exists

The single most expensive mistake with a high-level rooflight is deciding on electric operation after the scaffold has gone and the ceiling has been boarded and skimmed. At four or five metres, running a cable afterwards means either surface trunking across a feature ceiling or a tower and a great deal of making good.

The right sequence is to settle the powered specification before first fix, get the cable to the unit position while the roof structure is open, and leave the transformer somewhere that can be reached again without an access tower. That last point is missed constantly: a transformer buried in a sealed void above a stairwell is a problem stored up for later.

Even where a unit might end up manual, running a low-voltage cable to the position during first fix is cheap insurance in a tall space. The detail of that is on wiring an electric rooflight at first fix.

Planning for the day something needs attention

Every mechanism eventually needs looking at, and at height the access is the job rather than the work itself. Think about it once, at specification stage, rather than never.

Three questions are worth answering. Can a tower be erected under the unit, or does a stair flight or fixed furniture prevent it? Is the transformer and any control gear reachable without that tower? And is the unit a current model from a manufacturer who will still be making parts in ten years?

The last is a real argument for the mainstream ranges. We install VELUX, Fakro, Keylite and Roto units, and part of the reason is that a five-metre-high window is a poor place for an obscure product with an uncertain parts supply.

When a fixed light at high level is the honest answer

Not every high rooflight should open. If the room already has good ventilation at a usable height, if the volume is not one that stratifies, or if the position is such that an open sash would be exposed to driving rain from the prevailing south-westerly, a fixed light is the better specification.

A fixed unit has no mechanism to wear, no cable, no control, fewer air paths through the perimeter and a lower price, and at five metres up the things that do not exist are the things that never need reaching. Where daylight is the whole brief, this is the correct answer rather than the cheap one.

We are happy to say so. Specifying a motor into a position where the ventilation has no job to do is spending money on components that will sit unused above your head.

The dimensions we take under a high-level opening

At survey on a high unit we measure the vertical height from finished floor to the intended operating point, the pitch of the slope so the reach across the vault can be worked out, and the clear floor area beneath for future access. We look at where a person actually stands in the room, and we look for the things that get stood on.

We then set out the cable route and the transformer position with the ceiling still open, agree the control positions on the wall rather than on a drawing, and sequence the work with a qualified electrician who makes the connection to the fixed wiring and certifies that part. The roof is not left open overnight at any stage of the work.

The perimeter still decides whether the installation stays dry, and at height it is the part you will never inspect. Upstand height, falls, flashing laps and where the covering terminates against the frame are the four details that matter, and they are the reason our workmanship carries a ten-year guarantee. You get a range by email once we know the room, and a fixed price after the survey.