How do you paint and restore an exterior window frame?

It may sound like an old cliché, but it is true, windows are the eyes of a building. But over time, these eyes can begin to look old and tired, especially in older historical properties. Traditional windows are an integral part of the design of older buildings, so they need to be restored, repaired and repainted with great care.


However, even modern window frames can become in desperate need of a refresh. General wear and tear, harsh weather, bright sunlight, and pollution can all contribute to window frames looking dull and faded.  Painting and restoring window frames can make a huge difference to the look of a building and is one of the easiest and more effective ways to give your home an exterior makeover. Whether you are painting metal window frames or wood, here are some tips to give your window frames a new lease of life.

Tools you’ll need

  • Masking tape or masking pen
  • Flexible filler
  • Sandpaper
  • Primer or undercoat
  • Cutting-in brush
  • Small or medium paintbrush
  • Exterior paint for wood or metal

How to paint exterior window frames

1.    Clean the window frame

The frame needs to be clean and dry before painting. So, make sure you give it a thorough once over with a stiff hand brush to get rid of any cobwebs, dirt and dust.

window frame being prepped for painting

2.    Fill and smooth

Use a flexible filler to fill any cracks or holes on the window frame. Going with the grain of the wood, sand gently and then remove all the dust.

3.    Mask the glass

Use masking tape to mask around the window, leaving a 2mm gap to overlap onto the glass to seal out water. Alternatively, you can use a masking pen which will leave a layer of wax on the glass, so it stays paint-free. Once you’ve finished painting, you just need to remove the wax with a scraper.

4.    Prime the window frame

Apply a coat of undercoat or primer to the window frame and sill. If you use a standard gloss or satin paint, the primer will need to be weatherproof to give you a longer-lasting finish. If you are painting aluminium windows, you will need to apply a coat of metal primer to the frame to ensure the paint will adhere properly.

5.    Let the primer dry

You’ll need to let the primer dry before you begin painting. How long this will take will depend on the weather conditions and the paint you are using. For example, try to avoid painting when the weather is sweltering as the paint will start to dry and become sticky as you are painting.

6.    Start painting

Make sure you have chosen exterior paint that’s suitable for the type of window frame. Thoroughly stir your tin of paint and apply it to the window frame with a brush, pressing it into the corners. To get the best results, start with an angled cutting-in brush against the glass before swapping to a small to medium brush for the top and bottom horizontals.

powder coating and spraying aluminium window frames with black paint

Then paint the verticals and sill if neccessary. Using a spraying tool to coat the window frame with paint is another way to restore the appearance of window frames or change their colour. There are specialist window frame spraying paints available that provide protection against harsh weather and give a smooth finish.

7.    Dry and repeat

Leave the paint to dry completely before applying at least one more coat of paint. During your final coat, make sure the brushstrokes are in one direction, as this will give you a neater finish. Remove all of the masking tape before the final coat is dry. This will help to prevent your water sealing boarder from being lifted off with the tape. With a new dry coat of paint your window frames will be weatherproof in just one hour, while the colour can last for around ten years.

Window Painting and Restoration Services

Painting your window frames is an easy and very effective way to give your property or building a much-needed facelift. Our façade experts are working on a project to paint the timber frames and stone window cills at the prestigious Grade II Listed Fairfield Hall as part of an overall project to clean and restore the building.

At Building Transformation we can provide airless spray, spray, or roller applied non-streaking paints in a wide range of colours. Our paints are UV resistant, breathable, water repellent, and preservative, making them suitable for a range of materials and building types. Speak to a member of our team today to arrange a window painting or restoration solution for your building.