I have a deck that I built in 1986 with treated lumber, that last year we used a stain sealer on and the sealer was bled thru at mostly knot locations.
I have used clear sealer many times over the years on this deck. You would think that as old as the wood is this should not happen. I scrubbed the deck with stiff bristle brush and a strong cleaner, heavy on bleach, and it looked good after applying stain sealer, but then in spring it showed many bare spots at the knots.
What can I do to rectify this?