Yes. Opening versions are made across the flat roof ranges, hinged at one edge and operated by a pole, a winder or an electric actuator. On a single storey room it is the most effective vent position available, because warm air leaves at the highest point and draws replacement air in below.
Why the position is so good
Because it is where the warm air already is.
Warm air rises to the ceiling, so an opening at the top of a room lets it out directly and pulls cooler air in through a door or a window at low level.
A window at head height does neither nearly as well.
Manual options
A pole or a winder, and both assume somebody can reach.
A pole hooks into a catch and pushes the sash open, which is straightforward on a low ceiling and awkward at any height. A geared winder on a rod is easier to operate and more visible in the room.
Electric options
A chain or spindle actuator, operated from a switch or a handset.
It removes the reach problem entirely, and it is what most households end up wanting once they have tried a pole on a kitchen ceiling.
The cable is the decision
The most useful thing on this page, and it costs almost nothing at the right moment.
A powered unit needs a supply at the opening, which is a few metres and ten minutes while a ceiling is open, and a separate job with boards up afterwards.
Even where a manual unit is chosen, running the cable and capping it makes a future change simple.
Rain sensors
The accessory that makes an opening unit actually get used.
A sensor closes the unit when rain starts, which removes the reason people leave a rooflight shut all summer: the fear of being out or asleep when the weather turns.
On a deck above head height it earns its place.
Solar powered units
An option that removes the cable question on a retrofit.
Some ranges offer an integral photovoltaic cell and battery charged by daylight through the unit itself, operated by a handset.
Where running a cable would mean opening a ceiling, it is a genuinely useful answer.
How far they open
Modestly, and it is enough. Flat roof opening units generally lift a limited amount rather than swinging wide, which is sufficient for ventilation and keeps the sash controlled in wind.
They are not an access hatch, and where access is wanted that is a different product.
Roof access hatches
The separate product, and worth distinguishing. Where somebody needs to get onto a flat roof, an access hatch or a walk-on unit with an opening leaf is the right thing rather than an oversized ventilation unit.
It has different hardware, different sealing and different safety considerations.
Smoke ventilation
A different duty again and worth naming.
An automatic opening vent for smoke control is a specified system with its own standards, controls and testing, generally on a stairwell in a block.
It is not a domestic rooflight with a motor on it.
Does an opening unit leak more
Not if it is right, and there is a caveat.
An opening unit has a seal that a fixed one does not, and a seal is a component with a service life. Properly specified and maintained it is not a leak risk.
What fails on an exposed roof is ironmongery rather than the seal.
Restrictors in an exposed position
Worth having where wind is a factor.
A sash caught by a gust reaches the end of its travel as a shock load, and repeated over years that wears hinges and stays.
A restrictor or a wind sensor prevents most of it, and the reasoning is on the Rottingdean page.
Insect screens
A small accessory with a real use in a kitchen.
An opening unit at the top of a room draws insects toward it on a summer evening, and a retractable screen in the frame channel deals with it.
It is specified at order rather than added later on most ranges.
Background ventilation
A separate requirement from an opening sash, and it catches replacements out.
Where a room’s background ventilation came through the old unit, the replacement has to provide it, and a fixed unit with no vent does not.
It is checked at survey rather than at fitting.
Fixed and opening together
Frequently the best answer where two units are going in.
One opening unit for ventilation and one fixed for light gives the room what it needs for less than two opening ones, and they still match from outside.
Maintenance
Modest, and it is worth doing.
Hinges, stays and the seal want checking and cleaning occasionally so the seal compresses evenly, which is what keeps an opening unit working smoothly for decades.
Controls, and where the switch goes
A detail that decides whether a powered unit gets used at all.
A wall switch at light switch height by the door is used. A handset that has to be found first is used considerably less, and a switch behind furniture is not used at all.
It is worth deciding by standing in the room rather than on a drawing, and having both a switch and a handset rather than only the second.
Opening two units together
Available where a room has more than one, and worth specifying.
Powered units can be grouped so a single switch operates both, which on a kitchen with two rooflights is what makes night purging a habit rather than a chore.
It is a wiring decision made at installation rather than afterwards.
What we recommend on a flat roof
We recommend an opening unit in any kitchen or bathroom, run a cable while the ceiling is open whether or not a powered unit is chosen now, and specify a rain sensor on anything above head height.
The whole picture is on the flat roof rooflight installation page.
Thinking about this job? We survey across Worthing, West Sussex and the South Downs and give you a fixed price before any work starts, with a 10-year workmanship guarantee.