Do roof windows need servicing?
Yes, though the list is short and most of it is a homeowner job rather than a trade visit. A roof window sits in the coldest, wettest and most sun exposed plane of the building, and it has moving parts. Four things wear: the hinges and their friction pads, the gaskets, the air filter behind the top flap, and the internal finish on the sash. Twenty minutes twice a year keeps all four in order.
The sensible rhythm is a check in spring while the glass is being cleaned anyway, and a second in autumn before the leaves come down. Somewhere around the tenth year the finish on a timber sash wants proper attention. All of this applies to the units covered under VELUX window installation, and equally to Fakro, Keylite and Roto windows with different handles on them. How long the unit itself lasts before it wants changing is a separate question, and it sits on how long does a roof window last.
The two visits a year that cover it
Spring is the mechanical visit. Rotate the sash fully, drop the barrel bolt at the head so it locks in the cleaning position, and work through the moving parts while the outer face is in front of you. Hinges, friction pads, gaskets, filter, and the small drainage channels along the bottom edge of the sash.
Autumn is the water visit, and it happens from outside or from the loft rather than from a chair. It is about the flashing skirt, the tile courses immediately above the window, and anything that has grown or collected where water is meant to run. Neither visit takes long. Both cost far less than the conversation that follows a winter of quietly blocked drainage.
Washing the filter, and what a blocked one costs you
Every roof window with a ventilation flap has a filter behind it, usually a fine mesh or a foam strip clipped into the top of the sash. It keeps insects and the coarser airborne dust out of the room while the flap is open.
It clogs. In a rural position out towards the Blackwater villages, or under a mature tree, it clogs faster, and the effect is that the free area of the flap quietly halves without anyone noticing the room has stopped ventilating. The filter lifts out by hand, washes under a tap, dries and clips back. Once a year is enough in most positions. It is the highest value minute in the whole routine, because background ventilation is what keeps winter condensation off the inner pane in the first place.
Hinges, friction and a sash that drifts
A centre pivot sash is held at any angle by friction rather than by a catch, and that friction comes from brake pads bearing on the pivot housing. New, the sash stays exactly where it is put. After a decade in a south facing slope it may creep shut on its own, or need a shove to start moving at all.
Both are adjustable. The pivot housings carry a screw that sets the brake pressure, and a quarter turn is usually the difference between a sash that drifts and one that holds. The hinge itself wants a drop of light machine oil every few years, wiped rather than flooded, because oil that runs down the frame collects dust and marks the lining underneath it.
The barrel bolt, the keeps and a sash that no longer pulls tight
The bar handle at the head does two jobs. It draws the sash into the frame against the gaskets, and it holds it there. If the window feels loose in wind, or daylight is visible at a corner with the handle down, the lock keeps are the first thing to look at rather than the frame.
The keeps on the frame are slotted so they can be moved a couple of millimetres deeper, which takes up the compression that twenty years of gasket settlement has lost. The barrel bolt at the head, the one that holds the sash rotated in the cleaning position, deserves a proper look every spring. It is the component that stops a rotated sash swinging back onto your hands while you are leaning through the opening.
Gaskets, and the rubber that hardens before the glass does
The weather seal on a roof window is a pair of extruded gaskets in EPDM or silicone: one set into the frame for the sash to close onto, one running round the sash itself. They are the shortest lived component in the assembly and they age slowly rather than failing outright. The rubber loses elasticity, takes a permanent set in the shape of the closed sash, and stops springing back.
The symptoms are a draught at the head in a gale and a faint whistle on a north easterly. Replacement gaskets are sold as a moulded set against the size code and they push into a groove, so changing them is a screwdriver job rather than a glazing job. Doing it at around year fifteen on a window you intend to keep another decade is money well spent.
Lacquer on a pine sash, and the tenth year
The internal face of a pine unit carries a clear lacquer working against two things at once: ultraviolet coming through the glass, and moisture rising from the room. On a north facing landing it can still look new at twenty years. On a south facing slope over a shower room it will have gone dull and slightly chalky by ten.
Refreshing it is straightforward. Sand lightly with a fine abrasive, dust off, and lay on two thin coats of a water based acrylic lacquer with the sash rotated so the surface is horizontal and nothing runs. Keep it away from the gaskets, off the pivot bearings and out of the drainage channels along the bottom rail. Changing the appearance altogether is a bigger question, and it is answered on can a roof window be painted.
The flashing skirt in October
Outside, the habit worth forming is clearing the flashing skirt and the two or three tile courses immediately above the window each autumn. Moss travels down a slope with the water and lodges against the first obstruction it meets, which is the head flashing.
Behind that flashing sits a drainage gutter formed in the roof underlay, there to catch anything that has got past the tiles around the window and return it onto the felt below. It has a small cross section by design. A season of leaf mould and moss will bridge it, and water that should have run around the frame starts looking for another route down. A great many water problems around roof windows begin exactly here, as a drainage path that closed itself.
When a check turns into a specification decision
Some findings are not maintenance at all. Misting between the panes means the sealed unit has lost its seal and the desiccant inside the spacer bar is saturated, and no attention to the frame changes that. A sash that has dropped far enough that the gaskets no longer meet, or an outer frame that has gone brittle and chalky, has reached the end of its working life.
At that point the useful move is to read the data plate on the top edge of the sash, visible once it is rotated, which carries the size code. A like for like unit drops into the existing trimmed opening with a fresh flashing kit and fresh collars, usually inside a day. It is also the natural moment to change the glass specification or move from manual to electric, and skylight replacement sets out what that involves.
What the ten year guarantee is actually covering
Sunspire guarantees the workmanship for ten years, and it is worth being clear about what that guarantee is protecting, because it is the invisible half of the job. The underlay collar and its drainage gutter, the insulation collar, the vapour barrier collar, the flashing laps and the way the covering was re-laid into them. None of the five can be inspected once the tiles are back down.
The hinges, gaskets, filter and finish are the visible half, and the half a homeowner can genuinely look after. Between the two, a roof window set into a slope properly and given twenty minutes a year is among the least demanding things in the house.
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