How to finish wooden windows and doors

how to finish doors and windows

Finishing timber products correctly prolongs their life and stunning good looks.

The easiest way to give them the protection they need is to specify a factory finish. Our manufacturer, JELD-WEN, guarantees its paint finishes for ten years* so all you need do before installation is give them a light clean with a soft sponge and pH neutral soapy water.

DIY finishing

If you are a dab hand with a paintbrush, choose a branded primer and hi-build paint or stain, which can be purchased from most decorators’ centres and some retailers. Always use them in accordance with the instructions and to achieve the best finish, sand the wood between coats, allowing adequate drying time.

Freshly plastered walls should be completely dry before fitting wooden windows or doors to avoid rapid changes in humidity, excessive moisture penetration and warping.

External, patio and garage doors

On any external door, it is important that a suitable base sealer is used on the surfaces, all four edges and any cut outs for locks, hinges, letter plates, etc.

As soon as work on the door is complete, sand off marks caused by handling or exposure, ensure it is dust free and apply two coats of sealer/primer. Do not use wire wool or sanding materials on steel or iron elements.

Apply paint or stain, as above, in accordance with the manufacturer’s instructions. (Please note, JELD-WEN external ply, boarded and redwood doors are only suitable for paint.) Clear varnishes, waxes, polishes, oils, yacht varnish or lacquers** should not be used on external doors as they do not provide adequate protection.

In areas of severe exposure, cover your external door with a porch, hood or canopy and undertake regular maintenance to stop deterioration of its construction, the wood or finish.

Internal doors

Moulded doors need decorating using quality paint within 24 hours of fitting, paying particular attention to edges and any cut outs.

Flush veneer and pre-finished doors are ready to hang, unless trims are made, in which case they will need protecting with a polyurethane varnish.

Oak or primed feature doors can be painted, stained, varnished or lacquered to suit your preferences and the location.


Unfinished windows are described as being ‘in the white.’ This means a suitable hi-build paint or stain must be applied before they are exposed to the elements and further coats added in accordance with the manufacturer’s guidelines.

Ready primed windows need painting within three months of delivery and casements supplied with just a basecoat of stain, finished within a month. If you are using an opaque stain, a knotting treatment must be applied first. Should the basecoat deteriorate due to exposure, prepare and prime again before finishing.

Any cut surfaces, particularly those exposing an end grain, should be coated with a preservative or primer before the window is painted and fixed into position.

It is important to remember the sun can shorten the lifespan of black paint or other dark colours and Danish oils should never be used on JELD-WEN window products.


*Inspect annually and touch up if necessary.

**Lacquers are suitable for internal doors only.

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