Service and Maintenance

Wood maintenance

Although most of our products are now pre-painted, some still maintain a natural wood finish. The timber has received basic treatment and finished coating at the factory and can be cleaned with ordinary household cleaners. It must receive further treatment at least every four years and whenever required. Windows exposed to strong heat, strong sunlight and/or an especially high level of humidity (e.g. in a kitchen or bathroom) must however receive treatment at least every two years.

Surface maintenance: Remove surface treatment (varnish or paint). Ensure surface is clean and dry and apply primer to the timber. When dry, apply a coat of water-based acrylic varnish/paint (always follow the manufacturer's directions). Apply the same method to the affected areas if the varnish/paint is damaged. 

When you treat the wood, it is important to cover the gaskets to prevent varnish/paint rubbing off on the gaskets, as this will make the gaskets stiff/hard and spoil their effect.

Cleaning the pane

Clean the pane with a soft, clean, lint-free cloth/chamois leather/nonabrasive sponge or a clean, non-metal window squeegee. Clean water will normally be sufficient for cleaning the pane. Ordinary, non-abrasive household cleaners can also be used. Soft water is best for cleaning panes. Therefore, in hard-water areas add a small amount of detergent to soften the water or wipe off all excess water after cleaning.

  • Avoid contact from silicone with the pane 
  • Do not use any cleaning products containing abrasive particles 
  • Do not use chemical products for cleaning the pane 
  • Avoid contact with the pane from all sharp or abrasive objects including jewellery 
  • Never attempt to clean off dirt on the pane without first applying water 
  • If any works are taking place in the vicinity of the pane, protect the pane with a clean plastic sheet to prevent any splashes or staining from aggressive and abrasive compounds 

Cleaning the air filter

The air filter can be removed and washed with ordinary household cleaners. Fully rotate and secure the window in cleaning position, then remove the filter from the filter rail. New filters are available from VELUX and be bought as part of our maintenance kits (ZZZ 220). See dealer for details.

Cleaning the flashing

Leaves and other debris should be re moved from the flashing around the window once per year to allow rain water to flow freely.

Snow and ice

In areas with prolonged cold periods with heavy snowfall, considerable amounts of snow and ice may accumulate on the roof and a VELUX roof window could become covered with snow and ice for long periods. 

When the temperature rises, the window will often be one of the first places where the snow and ice starts melting.

It is important to make sure that water can always drain off from the roof and surrounding gutters.


When condensation forms on the glazing of your windows, you should take it as a warning sign that you should ventilate more often. Regular ventilation is the most efficient way of preventing condensation water from forming on your window glazing. 

Limit the amount of humidity:
  • If possible, do not dry your laundry inside the house. 
  • Close the doors of kitchens and bathrooms. 
  • Ventilate regularly for five minutes at least three or four times a day
  • If possible, maintain a constant room temperature of at least 68°F.