The short answer
A well-fitted VELUX window lasts for decades, but there is no single figure, because the parts age at different rates. The frame and sash tend to outlast the sealed glass, and the flashing and seals are usually the first parts to show their age. We look at all of them at the survey and tell you whether the window has years left or is due for replacement.
The parts age at different speeds
When people ask how long VELUX windows last, they usually mean the whole unit, but a roof window is several components working together. Each has its own lifespan, and the VELUX lifespan you experience depends on whichever part gives up first.
- The frame and sash, which are timber with a protective coating and tend to last longest if the coating is kept sound.
- The sealed glass unit, where the seal around the two panes can fail and let moisture in.
- The seals and gaskets, which harden and shrink with sun and frost.
- The flashing, which is the weathering around the frame and depends on the roof covering beside it.
- The moving parts, such as hinges, handles and any electric motor.
This is why an old window is rarely all good or all bad. A frame can be sound while the glass has misted, and a perfect pane can sit in a flashing that has failed.
What shortens the life of a roof window
A roof window works harder than a wall window. It takes sun at full strength, rain driven by wind and a steady stream of warm, damp air from the room below. Several conditions wear it faster.
- Poor installation, particularly flashing that is not lapped correctly with the tiles around it.
- Constant condensation, which soaks the lining and the lower frame.
- A bathroom or kitchen with little ventilation below the window.
- A south-facing slope, where the sun dries and cracks seals and coatings.
- Debris on the roof that holds water against the flashing, such as moss, leaves or a blocked valley.
The quality of the fit matters more than almost anything else. A window set square, flashed correctly and sealed to the underfelt will outlast one that is fitted in a hurry and left to cope. Our fitters work from the lower edge of the flashing upwards and test the opening and closing before leaving.
Signs the window is coming to the end of its life
The warnings are easy to spot if you know where to look.
- Misting or a grey film between the panes of glass.
- A sash that no longer closes squarely or that sticks in the frame.
- Damp marks on the lining or ceiling near the window.
- Draughts around the sash on a cold, windy day.
- Rust on the hinges or flaking on the coating of the frame.
One sign on its own does not condemn a window. Misted glass in a sound frame may only need a new glass unit, and fitting new glass into an existing frame is not a controlled fitting. Several signs together, or a frame that has absorbed water, point to replacing the whole unit. Our guide to replacing an old VELUX window explains how that job runs.
Keeping a window working for longer
A little attention each year pays back. These habits keep a roof window in good condition.
- Ventilate the room regularly so moisture leaves instead of settling on the glass.
- Wipe condensation from the sash and sill so it does not soak into the lining.
- Look over the roof side from the ground or from a window each year for moss, lifted tiles or blocked gutters.
- Keep the coating on the frame in good order by retouching chips with a suitable paint.
- Open and close the sash occasionally so hinges and seals do not seize.
Nothing here needs a specialist, but a professional look every so often catches faults you cannot see. The survey is free, so there is no cost to getting a straight opinion on an older window.
Why the age on the plate does not settle it
The data plate shows when the window was made, and that is a useful starting point, but age alone does not decide anything. A window facing a sheltered north slope in a well-ventilated bedroom can look good long after one over a steamy bathroom has failed. Equally, two windows made in the same year can behave very differently if one was flashed carefully and the other was not.
So we judge each window on its condition. We read the plate for the date and the code, then check the glass, the seals, the frame, the lining and the flashing one by one. You get a plain statement of what is worth keeping and what is not, and a fixed written quote for whichever route you choose. If the window can safely stay, we say so.
When the age of the window is a reason to replace it
Even a window that still works can be worth replacing if the energy performance has fallen behind. A whole-unit replacement brings Part L into play, and for an existing home that means a roof window at 1.4 W/m²K or in Window Energy Rating band B. That is usually a clear step up on glazing from several decades ago, so the room is warmer and quieter afterwards.
The work is notifiable, and the Building Control notification is something we deal with on your behalf. A 10-year workmanship guarantee covers the fitting, and the new unit is covered by the maker's own terms. For a look at the wider service, see our page on VELUX windows in Coventry.
