Clean the outside from the ground or a ladder against a solid wall, using a soft brush on a long pole and clean water, never by standing on the flat roof or the glass. Clean the inside from a stable platform with a soft cloth and a mild glass cleaner. Clear any debris around the upstand first.
Why do roof lanterns get so dirty?
Because they sit flat to the sky in the middle of a roof. A lantern catches everything that falls: leaves, seeds, bird droppings, pollen and dust. Flat roofs drain slowly, so dirt can collect around the base of the lantern too. In shady gardens, the glass and the glazing bars soon go green.
And because the lantern is in the middle of the roof, it's out of reach of a normal ladder, so it tends to be left.
Can you walk on a flat roof to clean a lantern?
It's best not to. Many flat roofs, especially on extensions, aren't designed to be walked on, and their covering can be damaged by foot traffic. Lantern glass must never be stood on. Falls from and through roofs are a well-known cause of serious injuries. The safe way is to reach the lantern without being on the roof at all.
How do you clean the outside safely?
With a soft brush on a long pole. A water-fed pole, used from the ground or from a ladder resting on a solid wall, can reach the middle of most lanterns. Work from the top of the lantern down, along each glazing bar, then rinse well.
- Brush off loose leaves and droppings first.
- Wet the glass and let any green film soften.
- Brush along the glazing bars, then across the glass.
- Rinse from the ridge down with plenty of water.
Purified water is ideal, because it dries without spots. Tap water on a sunny day can leave white marks across the glass.
What should you avoid?
The same things as on a conservatory roof. No pressure washers, which can force water past the seals and into the room below. No abrasive pads, which scratch. No harsh chemicals, especially if your lantern has a self-cleaning or solar-control coating. Our guide on why not to pressure wash a glass roof explains the risks.
How do you clean the inside?
From a stable platform, carefully. The inside of a lantern is often high above a kitchen island or a dining table. Use a proper step platform or a hop-up with a handrail rather than a chair on a table. A soft microfibre cloth and a mild glass cleaner, or water with a little washing-up liquid, is enough. Dry with a clean cloth to avoid streaks.
If the lantern is too high to reach safely, an extension pole with a soft head can do the inside glass from the floor.
What about the flat roof around it?
Clear debris away from the upstand. Leaves and moss collecting around the base of the lantern hold water against it and can block the roof's drainage. Clearing the area around the lantern, from a ladder at the edge with a long tool, helps the roof drain and keeps the base of the glass clean for longer.
How often should a roof lantern be cleaned?
Once or twice a year suits a lot of homes. Lanterns under trees, or on north-facing extensions, will need it more often. Many people like the outside done in spring, so the kitchen gets the most light through the summer.
When should you get help?
When you can't reach the middle safely from the ground or a wall. Our conservatory roof cleaning also covers roof lanterns, cleaned from the ground with pure water and soft brushes, across Essex.