How to paint varnished exterior window frames?

Mads86

Our interior and exterior window frames are either stained, varnished or both and we are wanting to paint them to protect the wood and provide better maintenance longevity (staining yearly vs painting 5 yearly). They have a glassy look and waxy feel so I’m thinking there must be a clear varnish or similar over the top of the stain but can’t be certain as it was done by the previous owners.

The frames are in various states of disrepair with some sections looking like damaged natural wood, flaking, water stains and stained/varnished finish as shown in pictures.

Can anyone help me to know how to prepare the surface so paint will adhere properly? And what products/paint to use to ensure a quality finish? We are leaning towards dulux monument paint.

Thank you!

MitchellMc

Welcome to the Bunnings Workshop community @Mads86. It's a pleasure to have you join us and many thanks for your question on preparing window frames.

You’ve essentially got two options here, depending on how much prep work you want to do.

Option 1:
Sand the frames right back to raw timber, removing all existing coatings. From there, apply a suitable primer and then your topcoat paint. This gives you the most reliable, long-term result.

Option 2:
Lightly sand the frames using around 240-grit sandpaper, making sure to remove any flaking or peeling varnish (as seen in your last image). After that, apply a specialised primer such as https://www.bunnings.com.au/dulux-1l-precision-white-maximum-strength-adhesion-primer_p1400848 , followed by your topcoat. This type of primer is designed to help paint adhere even in areas where some varnish may still remain.

From your first two images, it looks like most of the varnish has already peeled away, exposing raw timber. However, your mention of a glassy look and waxy feel suggests there may still be some coating left on the surface.

Because of that, you’ll need to either:

• Thoroughly sand everything back to raw timber, or
• Use a specialised adhesion primer to ensure proper paint bonding

Please let me know if you have any questions.

Mitchell