Can this be used over a newly painted deck? Paint is latex non waterproof. Valspar porch/floor paint

Thank you for your question. We apologize for the delay in response. In order to be effective, a stain must be able to penetrate. Surfaces must be sound and free of standing water. In order to achieve optimal results, it's best to remove the current product as best as possible. You can use a chemical stripper or sand the surface allowing the wood to become porous. Sincerely, Alex Cabot Customer Support