How many coats of failing paint? If it's a a single or thin coat, then I would try to hit it with a sodium Hydroxide based stripper and pressure wash it all off. This might even work with a heavier build of paint, but I have not tested that.

 

Sand and solid coat is the way to go. Stripping won't happen with paint.

 

On my last full-house stripping job, one of the sides had a painted cat-walk style deck floor. As I was pressure washing off the stripper from the siding, the first couple board of the cat walk, next to the siding, also lost all the top coat of paint. The stripper seems to have softened it to a point where pressure washing it easily took it all off. The rest of the paint that didn't get stripper on it wouldn't pressure wash off so the stripper must have worked on that paint. Perhaps it was solid stain, but I'm pretty sure it was latex whatever it was. Just one experience, so I'm not trying to dispute what PP is saying. I just thought it might be worth testing.

For applications of heavy quality paint, or multiple coats I wouldn't even try messing around with stripper. But if it's just one thin coat of failing behr, you might get lucky.

 

If it were paint with no primer and bad application (wet wood), stripper would take it off. When you are talking about uniformity of removing paint from a deck you would need a different (and very expensive) product. $50 per gallon and one gallon covers around 65 s.f. Also need an industrial airless to apply. All woodies have that one paint job they tried to strip with high hopes and it became a nightmare money pit.

 

It was done once. Maybe two coats. Probably one cause my brother in law put it on. I'm getting a new MITM powerwasher thru SW and it should be in monday. I might wash it after sanding to clean it but I don't want to balst all the paint chips all over and make a mess. I just have to get ity looking good for resale.

 

Stripping sounds like a nightmare. Every deck I ever did with my dad we just washed and recoated with stain or applied a first coat to a new deck. I have never used deck stripper or did any of that fancy ph stuff.