How to fix flaking paint on window frames?

Christine61

  

I suspect when my verandahs were closed in in the 40s (to accomodate 6 children in a 4 room cottage) that damp proofing wasn’t a high priority. The paint has lifted as shown and I wondered if this product, designed for concrete/masonry would work on wood? I last painted them 20 years ago (with a turps paint, properly sanded and undercoated) and it wasn’t a job I want to be repeating too often - 10 double hung windows. Also what paint would people recommend please and any other solutions to the damp problem. 
thanks in advance. 

MitchellMc

Welcome to the Bunnings Workshop community @Christine61. It's great to have you join us, and many thanks for your question about painting window frames.

I can see that the original paint wasn't entirely removed. What's likely happened over the years is that the underlying paint has continued to deteriorate, and that's caused your top coat to crack and flake away. Notice how you can see the underlying timber on the chipped sections? I suspect your newer paint bonded well to the old due to your prep work, but it's now the old paint that's let go of the timber.  However, 20 years is a decent amount of time, and unfortunately, it might just be time to repaint.

So, you have a couple of options. Prepare the surface as you did before scraping and sanding back the deteriorated areas until you reach paint that is well adhered, prime and then recoat. You'll likely get another 20 years with this method. Or, sand areas back to bare timber, prime and paint. With this method you'll likely get more than 20 years out of the paint job. It's that underlying paint layer that is going to determine how long you get before it deteriorates more.

I would not suggest you use the Damp Stop product, as it's not designed for that purpose. I am also not entirely convinced that dampness is the issue here. It could be contributing, though my money is on the original paint failing and flaking, which it will continue to do. If you want to use a product that blocks dampness, I'd recommend using Crommelin 1L Flat Aquablock Waterproof Primer Undercoat, which is more designed for this work. You can then topcoat it with Aquanamel, so you are only working with water-based paints and not turps.

Please let me know if you have any questions.

Mitchell