Will solid stain cover old stain on a deck?

"Mike in DE."

Might be able to minimize work by just restaining the deck, and solving the verticals issues later: Vertical parts of the deck wood will tend to last, as they drain fast and resist rot, even without finish. I like semitransparent stains, like Cabots, as they last for 3 yrs (here in N. CA) and prior to reapplication, require only light pressure washing to remove mildew stains and loose wood. Further, they soak in, so dont leave a significant surface residue to peel off later. If the deck boards are clean, you can either treat with deck prep solution from Home Depot, then wash off with a hose nozzle, or use a pressure sprayer to clean off the wood. I use pressure wash as the cleaners have toxics in them, and get into groundwater. When you redo the deck itself, you can restain the verticals using an exterior deck paint that computer matches the now-dried floor color. It would be difficult to remove your existing finish off the ballisters, etc. and stain will not stick well to impermeable surfaces like the Behr solid. I know this is a Rube Goldberg solution, but it's one idea. I suspect the deck wood was not properly primed/prepared, or thoroughly dry, or the paint was not mixed or applied incorrectly. Perhaps you dont have a full 1/4-3/8ths gap between deck boards, for drainage. I doubt if the prob was Behr itself, as it adhered and lasted well on your verticals. Look hard at the places where the stain lasted on the horizontals. That will give you a hint why it stuck in those areas. Protected from sun/rain, less light, better gaps, etc etc? Good Luck