DIY Doctor UK DIY Forums

Our oak windows and doors were fitted to our old cottage about 8 years ago. Despite my best efforts, rain penetration has caused areas of blackening. Sanding these off and recoating the wood has given a very patchy appearance because the original finish (Osmo oil then yacht varnish) has bleached the original colour I think my only option now is to use an opaque paint finish. Three questions; is a light sanding adequate prep before painting over yacht varnish, do I need a primer, and can anyone recommend a paint range with real lasting power
I’m thinking of a Matt or semi-matt finish in a colour that looks good on an old building.

Did your windows come with any guarantee?

It would be sad to paint them after such a short period of time.

Your first need to understand why it is happening, if it's a fungus, it would need to be addressed first.

Sadly no amount of sanding will help much, there are some acids on the market that can help eliminate the blackening.

Many thanks