Should you waterproof your plywood sub-floor?

[VanTalk00]

I don't think I see many people doing this, but I'm wondering if it might be a good idea.

I put some 1/2 inch foam board under it, and I intend to put down some sheet vinyl flooring over it, but I'm wondering what others' experience has been.  Has anyone not done it, then wished they had?  What was the result? warping?  bulging?

If you do seal it, what do you recommend?

Thanks,

Jim

 

[highdesertranger]

unless you plan on getting it soaking wet I wouldn't worry about it. if you do plan on getting it soaking wet I would use Marine plywood then waterproof it. highdesertranger

 

[B and C]

Make sure to treat all edges if you do treat it. I never did though.

 

[VanTalk00]

Well, I had some extra paint, so I decided to go ahead. Got the edges too.

Thanks

 

[Gr8ful]

You did it right. What ever you do to one side of wood ot lumber you need to do to all sides.

 

[LoupGarou]

I had the underside of my converted Cargo Body undercoated by Zebart.