I mistakenly painted our deck. I didn’t know it was originally stained. Now the paint is coming off and ends up in the house. What can I do?
You will need to sand off all of the paint and apply a quality deck stain. Work on just the floor if it is the only area affected, you can sand off the handrails later if needed.
Choose an oil base stain if available in you area, the water based stains have less penetration and can peel instead of fade. Also, a semi-transparent or semi-solid stain will penetrate more than a solid and have less chance of peeling.
You could scrape off the loose paint to a firm edge… then apply a coat of oil base EXTERIOR sealer primer to All Of It… then finish coat with a high grade Exterior Oil Base Porch & Deck Paint (1 coat to cover)… (Optionally you could SPACKLE all the scraped firm edges to give a smoother finish, before priming but this step is really not required for most outside work)! Good Luck…
My previous answer will give you a PROPERLY Re-Painted finish… IF however you want to go back to Stain… then you will need to perform the labor-intensive process of STRIPPING off the old paint with a Paint & Varnish Remover… then sand all surfaces… then you can Stain them again with a Oil Base Stain… finally after 2-3 days of curing, you will need to SEAL all surfaces with a good grade Deck Sealer, or Varnish them with a SPAR Varnish… Good Luck!