Why Won't My Roof Window Close?

Check for a simple obstruction first

Open the window fully and look along the edge of the sash and frame, inside and out. Leaves, moss, grit and the bits of old sealant that crumble off in cold weather all collect in the channel round the opening, and a pellet of hard debris can stop the sash seating. Wasps and spiders will build in the gaps, and in winter a thin skin of ice can hold the sash a few millimetres proud. Clear the channel with a soft brush and a damp cloth, taking care not to scrape the rubber seal, then try the window again. On a window that you can only reach by leaning out from a ladder, do not go outside to check; use the inside and a torch.

Also look at what has been added near the window. A blind with a loose bracket, a curtain pole, a new coat of paint on a timber lining or a bulging internal finish can all push against the sash as it swings through its arc.

Frame and sash that have moved

Timber roof windows, and the polyurethane or timber ones with a painted finish, swell in damp weather and shrink in dry. A window that closed last summer and sticks this winter is often just damp. More serious is a frame that has moved because the rafters beside it have shifted, or a sash that has dropped on its hinges and no longer lines up with the latch. Check the gap round the closed sash: if it is wide at the top and tight at the bottom, or the corner will not meet its seal, the sash is out of square.

Centre-pivot windows hold the sash on two pivot hinges halfway up the frame. Wear in these, or a bent pivot pin, lets the sash sag and stop short. Some models can be adjusted with the correct tool, while others need new hinges or a replacement sash. The model number is on the label inside the frame, and it decides which parts exist. Our page on replacing an old roof window covers the point at which repair stops making sense.

Brakes, springs and electric motors

Most centre-pivot windows have a friction brake or a spring that controls how freely the sash swings, so it holds in any position and does not slam. When that wears, the sash may swing through to the closed position too fast, bounce open again or refuse to stay shut. Some designs include a gas strut or a bar that can be tightened. On a top-hung window, check the stays and the hinge arms for bending.

Electric and solar windows have a motor and a control unit, and a fault there can leave the sash part-open. Check the control batteries or the power supply, and look for a rain sensor that has closed the window on its own and then tripped. A motor that hums but does not move points to a jammed mechanism, and one that is silent points to power or the control. Resetting the system following the maker's instructions is a fair first step. Beyond that, the unit needs a technician, since a forced sash can break the drive.

Leaks and cold are the reason to act

An open or part-closed roof window is a nuisance and more besides. It lets rain in at the lining, drives cold air into the loft room and, at the worst, lets a burst of wind bend the sash. If the window will not close at all, make it as safe as you can from inside and photograph the fault. If water has already reached the lining, our guide to leaking roof windows explains how to tell the flashing from the glazing.

When repair stops being worth it

Parts for older windows are not always available, and a sash that has warped, a frame that has rotted at the lower corners or a unit with failed seals all point towards replacement. A fair test is the combination of age, the number of faults and whether the window is still weathertight. If you are paying to repair a third problem on a window that is already past its best, a new one will usually cost less over a few years and will bring better insulation. Where a repair does make sense, such as a replacement hinge, a new seal set or a freshly adjusted catch, it can be done quickly without touching the roof covering around the frame.

We look at the frame, the hinges and the seals on site and can tell you whether the sash needs adjusting, a part replaced or the window renewing. The repair is photographed and quoted in writing before we start. Everything we do with roof glazing is outlined under our roof window service, and the price is fixed once we have seen the window.