How do I go about painting an already painted but tired windowsill?

Question

I am repainting the concrete windowsills in my house. The paint on them is old and peeling and in need of updating. Some of the paint comes off easily, the rest is OK. If I just scrape off the flaking paint and repaint them you will see the traces of the old paint underneath.(ie. the paint that seems to be alright). How do I treat them so that they look new. Is there some sort of filler that I can use for the whole sill before sanding and repainting?

Answer 1

You are doing the right thing by removing all the loose flaky paint, leave the paint that is sound. When you have finished scraping rub down with coarse grit paper. You will need to fill in the areas where the paint has been scraped as it will show up when you re-coat. For this any exterior filler will do i recommend tetrion if you can get it. Just "face fill", skim in the areas with the slight depression, when dry rub down smooth and re-paint.

Answer 2

Use external Pollyfilla

Answer 3

If you scrape/wirebrush the old paint, then use a good masonry paint e.g. Dulux Weathershield, the old paint edges will be invisible as the new paint has plenty of body and is matt which hides defects well.

Answer 4

You may consider gluing a wood or nylon sill to the existing concrete sill. This will give it a "sanitary" look and can be painted brand new with little work.