The internal timber, yes, and it takes paint well once the factory lacquer is properly keyed. The external cladding, technically yes but rarely worth doing, because a brush finish on exposed aluminium at that angle to the weather does not last and the factory colour underneath was fine. The white polyurethane units, no in any useful sense: paint does not bond to them reliably. And nothing on the moving weather line, the gasket, the hinges or the drainage channels, should ever see a brush at all.
Three surfaces, three different answers
People ask this as one question and it is really three. A roof window presents lacquered pine on the room side, a powder-coated or anodised aluminium cladding on the weather side, and on some models a white polyurethane skin over a timber core that replaces both. Each behaves completely differently under paint.
| Surface | Can it be painted | Worth doing |
|---|---|---|
| Internal lacquered pine | Yes | Often, and it lasts |
| External aluminium cladding | Yes, with the right primer | Rarely |
| White polyurethane skin | Poorly | No |
| Gasket, hinges, drainage, filter | No | Never |
What the factory lacquer actually is
The clear finish on a pine roof window is a water-based acrylic lacquer, sprayed and cured in the factory, and it is deliberately hard and slightly slippery. Paint straight onto it and you get an even coat that looks perfect for four months and then peels off the top rail in sheets, because nothing has bitten into anything.
It is also worth knowing that the timber under it is finger-jointed pine, not a hardwood, and it moves with humidity more than a wall frame does. A brittle finish over moving pine cracks at the joints, which is one of two reasons oil gloss is a poor choice here.
Preparing lacquer so paint holds
The preparation is the whole job. Skipping it is why so many painted roof windows look tired within a year.
- Take the blind off and open the window fully so you are working on a horizontal surface with the outer edge inboard.
- Wash the timber with sugar soap and let it dry completely. Grease from hands sits on the lower rail and the handle area more than anywhere.
- Key the whole surface with 180 to 240 grit abrasive paper until the sheen is gone everywhere. A dull, even, slightly chalky look is the target. Any glossy area you miss will be the first place it lifts.
- Dust off, then wipe with a barely damp cloth and let it dry.
- Mask the glass at the glazing bead, and mask the gasket properly rather than approximately.
- One coat of a water-based adhesion primer, thinly. Two thin top coats of a water-based acrylic eggshell or satin.
Thin coats matter more than the number of them. A heavy coat on a rebate stops the sash closing evenly, and the point where paint has been allowed to build up in a corner is the point where the sash starts to bind.
Why water-based, and why not gloss
Traditional oil gloss yellows badly, and it yellows fastest under strong ultraviolet light, which is the one thing a roof window has more of than any other joinery in the house. A white oil gloss on a south-facing roof window will be visibly cream within two summers.
Oil gloss is also the more brittle film, and it stays slightly soft for weeks, which on a window that closes onto a gasket means the two surfaces stick together and tear when you next open it. A water-based acrylic satin is through-cured in days, holds its colour, and flexes with the pine.
The parts that must stay unpainted
There is a short list and it is not negotiable. The perimeter gasket, because paint hardens rubber and destroys the seal. The hinge and pivot assemblies, including the friction pads, because the mechanism is set by friction and paint changes it. The drainage channels and weep openings in the bottom of the frame, because a bead of paint in a channel puts water where it has no route out. The ventilation filter and the flap it sits in. The data plate on the sash, which carries the model, the size code and the year, and which you will want legible the day you need glass.
Mask them or take them off. On most units the filter pulls out and the handle unscrews in under a minute, and both come back on cleanly.
Painting the external cladding, and why we usually advise against it
The outer face is aluminium, factory finished in grey, and it is doing a job. It has to shed water, take ultraviolet light all day, and stay stable across a forty degree temperature swing. Brush-applied paint on that surface needs an etch primer and a two-pack topcoat to have any real chance, and even then it will not match the durability of what was on there.
Then there is access. Painting the outside means being on the roof, working over a covering you can damage, for a cosmetic change on a surface most people cannot see from the ground. Where the colour genuinely matters, in a conservation area or against a specific slate, the sensible answer is to order the unit with a factory-finished cladding in the colour you want, which several manufacturers offer, or to specify a conservation-pattern unit that sits flush and reads as dark glass anyway.
Polyurethane units and why paint slides off them
The white units are a moulded polyurethane skin over a timber core, and that skin is chosen precisely because it is inert, non-porous and easy to wipe. Those are exactly the properties that stop paint bonding. There are specialist plastic primers that will hold on the flat faces for a while, but on the rebates and the arrises where a cloth passes daily, it lifts.
The honest answer is that if you want a colour other than white on that style of frame, you are buying the wrong frame. Buy the timber version and paint it, or accept the white. More on the difference on the timber and polyurethane frames page.
The reveal is a separate job, and often the one that matters
Half the people who ask about painting a roof window actually want the plasterboard reveal around it to look better. That is a different piece of work and a much easier one. The rule that matters up there is that the reveal returns should be splayed, vertical at the head and horizontal at the cill, so daylight spreads into the room and warm air washes across the glass. A square reveal makes the window look like a hole and encourages condensation at the bottom edge.
Paint the reveal the same white as the ceiling rather than the wall colour, and it will read as light rather than as an opening. Where the sill is doing double duty as a shelf, the cill height page covers the geometry.
Where we come into it
Decorating is not our trade and we do not pretend otherwise. Where we help is at the specification end, before there is anything to paint: choosing a frame material that suits the room, ordering an external finish that suits the roof, and setting the reveal so the plasterer leaves you something worth decorating.
We install and replace roof windows and rooflights only, across Oxford and up to twenty five miles by road. Fifteen years in the trade, VELUX, Fakro, Keylite and Roto units fitted, Building Control notification handled, the roof never open overnight, and a ten-year workmanship guarantee. A range by email first, then a fixed price after a survey. 01865 704245.
Helpful reading on this
Costs, comparisons and the questions we are asked most.
Tell us about your roof
We start with the building, the covering and the slope. Then we tell you what will suit it, and what it will cost, as a fixed written number.
- Surveyed before it is priced
- 10-year workmanship guarantee
- Building Control notification handled
- New installations and replacements