Electric rooflight motor failure usually comes from one of three things: a worn chain actuator that has run thousands of cycles against a stiffening gasket, moisture reaching the control board or connector block, or chloride corrosion seizing the actuator bracket on a coastal property. Age and exposure decide which. A unit failing after twelve to fifteen years has reached the end of its service life.
An actuator is a small motor, a gearbox and a drive chain, sitting in a frame that is outdoors on one side and indoors on the other. It is asked to run a sash home against a compressed gasket, in rain, in frost, and in salt air if you are anywhere near Felixstowe or Harwich. Twenty years of that is a lot to ask of a component the size of a paperback.
The three failure modes, in order of how often we find them
1. Mechanical wear in the actuator
The motor windings almost never burn out. What wears is everything between the motor and the sash: the plastic gear train, the chain links, the pivot pin at the sash bracket. A chain actuator on a kitchen rooflight cycled twice a day is doing something in the region of 15,000 cycles across twenty years, and the gearbox is rated for a domestic duty, not a commercial one.
What it sounds like matters. A worn gear train whines or clatters and the sash moves in steps rather than smoothly. A chain that has stretched or a bent link will bind at one point in the travel and stall there every time, always at the same position. A gearbox that has stripped will hum with no movement at all, which people usually report as “the motor is dead” when the motor is the one part still working.
2. Moisture in the control board or the connections
Control electronics fail from damp far more often than from age. The usual routes are a cable entry that was never sealed properly, a control unit sited in a cold roof void where it condenses every autumn night, or water tracking down the cable itself into the terminal block.
Condensation is the quiet one. A control box in an unheated void goes through a dew cycle most nights between September and March. Salt or dust on the board turns that moisture into a conductive film, and the first symptom is intermittent behaviour rather than a clean failure: the unit works in the afternoon and not first thing, or it runs one direction and not the other.
3. Salt corrosion, on the coast
Within about a mile of open sea at Felixstowe, Clacton, Harwich, Frinton, Aldeburgh or Southwold, chloride attack is the dominant failure cause and it arrives years earlier than wear would. Three specific places:
- The actuator bracket and its fixings. Grade 304 stainless pits under chloride attack. We fit 316L throughout on coastal work because the molybdenum content is what resists it. A seized bracket fixing loads the actuator sideways and kills the gearbox.
- The rain sensor pad. Salt is conductive when damp and hygroscopic when dry, so a contaminated pad reads wet in humid air and holds the unit closed. That is not a motor fault at all, and it gets reported as one constantly.
- Cable entries and connector blocks. Salt-laden damp air tracks in at any unsealed penetration and corrodes the terminals green.
Estuarine locations, Woodbridge, Wivenhoe, Manningtree, Shotley and Pin Mill, carry moderate salt loading rather than open-sea conditions. Corrosion shows up there, later and milder. Inland at Kesgrave, Stowmarket or Bury St Edmunds it is simply not the cause, and you should look at wear and damp instead.
Telling a control fault from a mechanical one
You can narrow this down from inside the room without going anywhere near the roof. Never get on a roof to investigate a rooflight, and never force a sash by hand.
| What you observe | Likely cause |
|---|---|
| No sound at all, no movement, other controls also dead | Power or control fault: supply, fuse in the spur, or the control board |
| Motor audibly runs, sash does not move | Mechanical: stripped gear train or a detached chain |
| Stalls at the same point in the travel every time | Mechanical: bent chain link, binding sash, or a seized bracket |
| Works sometimes, usually better in dry weather | Moisture in the control board or a corroded connection |
| Closes itself repeatedly in dry conditions | Rain sensor contamination, not a motor fault |
| Wall switch works, handset does not | Handset battery or lost pairing, not the actuator |
| Opens but will not close | Limit switch, end-stop setting, or one direction of the control board |
Two checks are worth doing first, in this order. Change the handset battery and try the wall switch, which separates the control layer from the drive. Then check the fused spur that feeds the unit, because a blown 3A fuse looks exactly like a dead motor. If the unit is on a solar model, neither applies and you are looking at the battery, which after eight to twelve years is a normal end-of-life item.
If the unit is stuck open and it is raining. Isolate the power at the fused spur or the consumer unit, protect the floor below, and book a survey. Do not go up to it and do not pull the sash. Our page on a rooflight stuck open in the rain sets out the containment steps properly.
What we do about it, and what we do not
We do not repair actuators, rewind motors, dry out control boards or replace gearboxes. That is not a gap in the service, it is a deliberate position. A twenty year old rooflight with a failed actuator has a frame, seals and glazing units of the same age, and a replacement mechanism bolted into perished gaskets buys you a season before something else goes.
What we do is diagnose the unit at survey, tell you plainly which of the three failure modes you have, and quote a full replacement. A like-for-like electric roof window replacement runs £1,600 to £2,300 supply and fit, one day on site, with a 10-year workmanship guarantee. Part L requires a replacement rooflight in an existing dwelling to achieve a whole-unit U-value of 2.2 W/m²K or better, so the new unit is materially warmer than the one it replaces.
If your existing unit is a manual roof window of the right generation, a solar conversion kit at £520 to £850 is sometimes the cheaper answer. That is covered on retrofitting a motor to an old rooflight, which explains where the compatibility limits sit.
Can a failed rooflight motor be replaced on its own?
Physically, sometimes, if the model is current and the parts are still made. We do not offer it. On a unit old enough for the actuator to have worn out, the seals, the sash and the glazing are the same age, and the sensible spend is a new unit with a fresh guarantee rather than a new mechanism in a tired frame.
How long should an electric rooflight actuator last?
Inland, on normal domestic use, twelve to fifteen years is a fair expectation and many run longer. Within a mile of open sea, expect less unless the unit was specified with 316L stainless and sealed cable entries from the start. Solar batteries are a separate item at roughly eight to twelve years, and they are replaceable.
Get it diagnosed and quoted
Tell us the age of the unit, the make if you know it, what it does when you press the switch, and roughly where the property sits. We survey it, identify the failure, and give you one fixed written price for replacement covering the rooflight, the actuator, the controls and the weathering.
Background on the mechanism itself is on how an electric rooflight opens, and when an electric rooflight needs replacing covers the age and condition thresholds. The full picture on specification, prices and coastal detail sits on our electric skylight installation page.
Request a fixed quote for a replacement across Ipswich, Suffolk and north Essex.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.