I want to paint over some old oak windows and porch that have turned black. I am told that the black will come through the paint and I am led to believe that is (at least in part) because it is acidic. You have products that act as barriers in almost every circumstance. Do you have one that would paint over the windows as a primer, that I could then paint over with a final colour? Can any paint be used over a barrier of this type or do you have a particular range that must be used? I am looking to use a French Grey surface coat. Many Thanks Russell Abson
This black staining can be caused by ferrous fittings, nails or screws corroding and reacting with the tannic acid in the timber.
Assuming the timber is clean, dry, sound and prepared we can recommend Zinsser Peel Stop followed by Zinsser Cover Stain top coated with Zinsser AllCoat Exterior (Water Based).
On horizontal surfaces such as window sills or heavily exposed areas we would recommend 3 coats of Zinsser AllCoat Exterior Matt (Water Based).
The Zinsser Allcoat is available in 4,000+ RAL, NCS, and British Standard colours, including BS 630 French Grey, with a choice of matt, satin or gloss finishes.