A roof window purchased from a DIY store faces the same challenges as a model installed by a certified installer: rain, UV rays, frost, pollen, moss. The difference in longevity between two identical Velux windows rarely lies in the product itself, but in the regularity and quality of maintenance applied to the frame, glazing, and roof perimeter.
Roof Environment: What Degrades a Velux Before the Velux Itself
Most maintenance guides focus on the window. However, the problem starts around it. A displaced or cracked tile near the frame alters the runoff of rainwater, which eventually stagnates against the Velux’s sealing connection.
Gutters clogged with leaves or roofing sand create a capillary rise effect along the zinc or lead flashing. Checking the condition of the tiles and gutters protects the Velux more effectively than cleaning the glazing.
Before any intervention on the window, a visual inspection of the surrounding roof, which can be done from the inside by tilting the sash or from the ground with binoculars, allows you to spot missing tiles, thick moss that retains moisture, and rust stains on the surrounding metal elements. This reflex, to be adopted at least twice a year (after winter and after autumn), prevents infiltrations that the Velux seal alone cannot compensate for.
Knowing how to maintain a Velux Brico Dépôt therefore requires considering the window as an integrated part of a roofing system, not as an isolated object.
Sealing Joints and Air Filter: Key Parts to Monitor
The peripheral sealing joint ensures thermal insulation and waterproofing between the fixed frame and the sash. Over time, this joint hardens, cracks, and loses its elasticity. A degraded joint is indicated by the appearance of abnormal condensation on the bottom of the interior glazing or a slight draft perceptible when the sash is closed.
Replacing a joint does not require removing the window. Compatible replacement joints can be found as spare parts, referenced by the dimension code listed on the Velux identification plate (visible at the top of the frame, with the sash in the tilted position).
The Often Overlooked Air Filter
The ventilation bar integrated into the Velux contains a filter that traps dust and pollen. A clogged filter reduces air renewal and encourages indoor condensation. Simply removing it, rinsing it under warm water, and letting it air dry is sufficient. This operation takes a few minutes and should be repeated at least once per season.
- Visually check the peripheral joint at each change of season by fully tilting the sash
- Clean the filter of the ventilation bar every three months, more frequently in urban or pollen-heavy areas
- Lubricate the hinges and opening mechanism with a fine oil like petroleum jelly once a year to avoid stiff points
- Check the condition of the external sealing connection (lead or aluminum flashing) at the same time as the adjacent tiles
Cleaning the Glazing and Maintaining the Frame According to the Material
The glazing of a Velux is double or triple glazed and treated. Abrasive or ammonia-based products attack the surface treatment and reduce the self-cleaning properties of the outer glass when it has them.
A soft cloth with slightly soapy warm water (neutral soap, like diluted Marseille soap) is sufficient for the interior side. The exterior side is cleaned by tilting the sash, without going onto the roof. For stubborn stains, a rubber squeegee provides a clean result without the risk of scratching.
Wood Frame or Polyurethane Frame
Velux with wood frames require surface treatment every few years. The original stain or varnish eventually chips due to indoor condensation, especially in humid rooms (bathroom, kitchen). A light sanding followed by a coat of microporous stain restores protection.
White polyurethane frames, common in ranges sold at DIY stores, do not require treatment but can sometimes yellow with UV exposure. Cleaning with soapy water and immediate wiping limits this phenomenon. A polyurethane frame should never be sanded, as it risks destroying the finish layer.
Solar Protection and Summer Comfort: A Maintenance Issue Often Overlooked
Recent user feedback highlights summer overheating as the main problem with roof windows. A Velux facing south or west without external protection can turn an attic into a sauna as early as May.
The external roller shutter remains the most effective solution to block heat before it reaches the glazing. Its maintenance consists of cleaning the aluminum slats and the box twice a year, checking the smooth operation of the curtain, and inspecting the electrical or solar supply to the motor.
A practical tip is to apply diluted Meudon white on the exterior side of the glazing during heatwaves. This natural product, long used on greenhouses, reflects part of the solar radiation and can be easily removed with clear water. This temporary method complements a shade or shutter without replacing them.
Maintaining the Velux and Deciding on Replacement
A well-maintained Velux lasts several decades. When the joints are replaced regularly, the mechanism is lubricated, and the surrounding covering is kept in good condition, the window retains its thermal and acoustic insulation performance.
Replacement becomes relevant when the double glazing shows permanent fogging between the two panes (a sign of seal failure) or when the wood of the frame is structurally damaged by moisture. In this case, several financial aids may apply in 2026, including MaPrimeRénov’, energy savings certificates (CEE), eco-PTZ, and reduced VAT, subject to performance and housing age conditions.
As long as the glazing remains watertight and the frame shows no rot, regular maintenance remains more cost-effective than replacement. The cumulative cost of wear parts (joints, filters, lubricating oil) over several years remains marginal compared to the price of a newly installed window.