The roof window in a converted loft is the one component in a house expected to work for twenty years with nobody touching it. Across the terraces of W4, where third storeys have been carved out of roof space on a large scale, the first sign that this is optimistic arrives as a damp patch on the plasterboard beside the frame, and it is rarely the leak it appears to be.
The wet edge that is not a leak
A roof window is the coldest surface in a warm room. Air rises to the highest point of the house carrying whatever moisture the household has produced that day, and there it meets glass and a frame sitting at outdoor temperature. Condensation forms, runs down the pane, gathers in the drainage channel along the bottom of the sash and eventually spills onto the timber below. A genuine leak stains in a ring and appears within hours of heavy rain; condensation arrives on cold mornings and vanishes in July. Telling the two apart before anything is dismantled saves a great deal of pointless work.
The flap nobody opens and the filter behind it
Almost every unit of this type has a ventilation flap built into the top of the sash with a small filter behind it. Left open, it gives the room a trickle of air and keeps the glass warmer than it would otherwise be. In practice the flap is shut during the first cold week after a conversion is signed off and never opened again, while the filter fills with dust until it passes nothing at all. In a room only just finished, building dust reaches that filter within weeks, which is one reason a thorough clean afterwards is worth arranging through trusted post-renovation cleaning in Ealing.
Handles, friction pads and a sash that will not stay put
Operation degrades slowly enough that nobody notices. Pivot bearings dry out, the friction pads holding the sash open at an angle wear smooth, and the handle catch stops engaging cleanly in its keep. A window that swings shut on its own, or that has to be forced the last few millimetres, is usually adjustable: pads are tightened, the keep moved a fraction, the pivots cleaned and lubricated with something that will not hold grit. Forcing a stiff sash week after week is what eventually cracks a frame at the corner, and no adjustment fixes that.
Where the unit meets the roof covering
Outside, the window sits in a flashing kit that sheds water over the covering below and carries it around the sides. Moss, leaf litter and grit washed off the slope collect in the apron above the head of the window, and once that dams, water works into the joint. Clearing it is a roof-level task carried out from a ladder and a crawling board, not by leaning out of the opening, which is how most accidents on this work happen. Tall terraces here have rear slopes that are awkward to reach, a difficulty shared by period stock elsewhere in London and covered by handyman for period property in Paddington.
What the marks on the reveal are saying
Where condensation has run for a couple of winters, the plasterboard reveal goes soft at the bottom corners and the paint lifts. Dark spotting there has stopped being a window fault: the surface has been wet long enough to need proper treatment before redecoration, and that stage is work for our nearby specialists. Cutting back to sound board, allowing the timber to dry, and only then re-setting and painting is the order that lasts. Fresh paint over a damp reveal buys a few months at most.
The void behind the sloping walls
A conversion leaves a triangular space behind each sloping wall, ventilated to the outside at the eaves. Squirrels and nesting birds find those openings, and the scratching is heard in the room below long before anything is seen. Blocking an eaves vent to keep them out causes condensation trouble of its own, so the entry point is dealt with properly rather than stuffed, and the removal itself is a matter for pest control cover across Chiswick.
What a service visit covers
A visit on a roof window means cleaning and lubricating the pivots, washing or renewing the filter, adjusting the friction pads and catch, clearing the drainage channel and reporting on the flashing from outside. Time on site is what the work is charged against, and a second or third window on the same visit takes far less than twice as long. Replacement handles and pad sets are ordered against the data plate inside the sash, so photographing it beforehand helps. Other jobs that can be added to the same call appear on handyman services nationwide.
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