How to look after a roof window

Dirt on a roof window builds up quickly, because the glass faces the sky and collects dust, pollen and bird droppings. Use warm water with a little mild washing-up liquid and a soft cloth or sponge. Avoid abrasive pads and strong solvents, which scratch glass and dull the finish on the frame. Many roof windows tilt or rotate so that the outer pane can be reached from inside, and that is the safe way to do it.

Wipe the frame at the same time, and the rubber gasket, the soft seal that runs round the sash. Dirt trapped there wears the rubber and stops it sealing. Dry the frame afterwards, as water left on timber or a painted finish for long periods does harm.

What not to use

Do not use a pressure washer on the glass or the seals. Water forced under the frame can find its way past the flashing. MyBuilder's 2026 cleaning guide warns that a pressure jet can harm fragile roof coverings, and the same reasoning holds near a window. Never lean out of an opening on a slope to reach the glass, or stand on the roof. If it cannot be reached from the room, it is a job for someone with a roof ladder and a harness.

Open and close the window fully, and listen to it. A smooth, quiet action tells you the hinges and the opening bar are in good condition. Stiffness, grinding or a sash that does not sit square all point to wear or something in the way.

Check these points once or twice a year:

• The gasket round the sash for cracks, flattened sections or gaps.
• The corners of the frame, where sealant meets timber.
• The hinges and the pivot bar for rust and play.
• The vent flap, if there is one, for blocked slots or loose catches.
• The paint or lacquer on a timber frame, particularly the bottom rail.

A touch of silicone-free lubricant on moving metal parts helps, but keep it off the rubber and the glass. A hardened gasket can sometimes be replaced as a spare part, which is cheaper than a new window. If the sash is out of square or the glass has clouded inside the unit, the answer may be different, and our guide on replacing roof window glass deals with it.

The flashing is the set of metal pieces that close off the joint where frame meets roof covering. On most roofs it is a kit made for the window, in aluminium or in lead. Lead flashing can last a long time when correctly installed: MyJobQuote, in a 2026 update, says over 80 years, and more for the heavier codes. A kit in coated aluminium varies with the finish and the exposure.

From inside the loft, look for staining on the timbers round the window, damp insulation and chinks of light. From outside, a pair of binoculars from the ground does the job. Look for lifted or slipped flashing, tiles or slates that have moved beside the frame, and moss collecting above the window where it holds water against the metal.

Keep the area above the window clear. Leaves and moss in the gap behind the top flashing channel rain towards the frame. Hand removal of moss is the gentle method. MyBuilder's 2026 guide puts manual scraping at about £5 to £10 per m², and a roof clean by a professional is a job for the roof, not for the owner on a ladder.

Look at the lining, the sloping board that finishes the opening inside. Damp patches, peeling paint or dark spots mean moisture is arriving from somewhere. It could be rain, but condensation is just as common, especially in bedrooms and bathrooms. Wiping the window and the sill dry in the morning, opening the vent flap for a few minutes and using an extractor in a bathroom all help.

If you cannot tell condensation from a leak, wait for rain and look again. A mark that appears during or just after rain, away from the glass, points to the flashing. A mark that follows cold nights points to condensation. Our guide to why roof windows leak and how they are fixed sets out the tests in more detail.

Blinds are worth a thought. A blind that sits tight against the glass can trap moisture, and a dark, heavy blind can raise the temperature of the frame in sun. Open it for a while every day.

A short list covers most of what a roof window needs.

1. Spring: clean the glass and frame, check the seals and hinges, and oil moving metal.
2. Autumn: clear leaves and moss from around the flashing, look at the loft side for damp, and check the paint on timber frames.
3. After a storm: look for slipped tiles, loose flashing and stains.

Stay on the ground or inside. A professional inspection is worth booking when the window is old, when you have spotted a stain, or before you sell. MyBuilder's 2026 inspection guide gives £150 to £500 for a roof survey, and a standard visit at £150 to £250. Our survey records the window, flashing and surrounding covering in photographs, and a written quote follows.

If the routine reveals a fault, you have a few options. A small repair is cheaper than a failed seal. If the whole unit is tired, think about whether a bigger change suits the room, as our comparison of a dormer or roof window explains for lofts. Security matters as well, and our answer on roof window security covers locks and opening limits. Work we carry out comes with a written 10-year workmanship guarantee, and the full range is on our roof windows and skylights page.