Painting the inside of a wooden window frame can be a trickier job than you think. It’s easy to make a mistake and paint over pre-decorated walls, or spill onto the window itself. There’s also the dreaded carpet-drip you’ll need to steer clear of – painting a frame is not an easy task for amateur decorators, but (as always!) the right tools and preparation will help you achieve a high quality finish.

A good paint is essential. There are oil-based and water-based paints that are specifically designed for woodwork, and you also have options on how glossy you want the finish to be. Oil paints are traditionally considered to be the superior finishes for woodwork as they form a deeper bond with wood, whereas a water-based (acrylic) paint adheres more specifically to the surface of the wood. There are, however, numerous advantages of water-based paints – most significantly the quick drying times, ease of washing out brushes (rinse them in water) and with virtually zero VOCs, they are the most environmentally friendly finishes available. Little Greene make both oil-based and water-based versions of their eggshell (low sheen) and gloss (high sheen) finishes. ‘Intelligent Eggshell’ is the most popular choice – it has a very smart, low sheen finish and is water-based, but formulated to behave like an oil paint – to resist wear and tear and, crucially, moisture.

Before you get started, ensure that you have protected any areas you don’t want to paint, using masking tape. This includes catches, hinges and handles – you might consider removing them completely. Give all the surfaces (including the glass) a thorough clean before you get going, removing the likelihood of dirt, grime or dust being mixed into your paint. If the surface is previously painted and in sound condition, a rub-back with sandpaper is sufficient preparation. If painting new wood you will need to use the appropriate Primer Undercoat, and if the surface is flaking or powdery you will need to strip it right back – the new painted surface will only perform well if the one underneath it is sound. Using a good quality tape that won’t allow the paint to bleed underneath, tape the edges of the windowpane, flush with the edge of the frame.

Look at the area around where you will be painting. Cover the carpet and the wall directly below the window if you can. This can save time and money, especially if you no longer have leftover paint in which your walls have been painted.

With a good quality brush at the ready (one that won’t lose bristles and can maintain a flat edge – an angled brush is good), stir your paint, ensuring consistency throughout the tin. It’s good practice to decant some of the paint into a separate container and reseal the tin (it prevents the paint in the tin from evaporation or being contaminated) and start your coverage of the horizontal rails. Some windows won’t have horizontal or vertical cross-pieces (known as bars, rails and/or muntins), but if yours does, make sure ALL the glass panes are all taped. Painting from the centre outwards is a good technique for maintaining control, and concentrate on keeping your brushstrokes long and consistent. With detailed work like this, you will need to pay special attention to avoid drips from the edges and pooling in the corners. Next, move onto the outside frame.

You may need to switch to a smaller brush for the underneath of the window sill; paint from the wall outwards. Finish on the top surface of the sill and, leaving everything where it is, let the window dry in a well-ventilated environment. Note that if it’s windy outside, opening the window is not necessarily the best way to provide ventilation – drying paint is vunerable to loose particles in the air. The tape should only be removed when fully dry; run a sharp knife blade along the edge to of the tape to ensure a really crisp result.