Latex paint has 2 problems.
- If water gets behind it, you may end up replacing wood.
- The substrate must be compatible for proper adhesion, or the end
result is a mess or worse.

What you save in a longer life can end up meaning more work to repaint
versus a simple clean & overcoat.


The original overcoatable paint sounds like a preservative woodstain?
- Linseed oil might be a good choice
- It comes in a wide variety of colours, long lasting, when it fades
you touch up
- Fully overcoatable without difficulty

The problem with linseed paint is drying time & application
temperature.

I would think carefully before using a "waterproof skin" latex paint.
Every time I take Weathershield off I find wet wood underneath and the
8 year lifespan claims are ******** if your wood is not acacia. Even
Sikkens latest paints whilst claiming decade-plus are only better in
that they are overcoatable like a woodstain.