Laying down plywood over old plank subfloor


Old 07-07-19, 02:20 PM
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Laying down plywood over old plank subfloor

I'm getting ready to install new luxury vinyl flooring. In order to prep my old floor for it, I've opted to lay down new plywood. The current floor is 3/4 in pine planks, with no subfloor. I wish I could refinish them, however there has just been too much wear and tear over the years. With that being said, my biggest challenge is leveling the old floor enough to put down the plywood. Some of the rooms have a bit of a slope towards one side of the house. I would rather not pry up the existing planks to shim across the joists if I can avoid it, so I'm looking for any wild ideas that anyone might have to get everything on the same plane.
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Old 07-07-19, 06:44 PM
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Floors need flat not necessarily level. Use T&G ply or advantech and re-evaluate after you have installed. It should smooth out some of the irregularities. Screw the ply/advantech down with deck screws for strength. I usually lay a layer of 15# felt paper between the layers.
Old 07-07-19, 06:45 PM
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Your flooring instructions will tell you how flat the floor needs to be... and the radius (area) that needs to be within that tolerance. I would say you probably just need to shim on top of your subfloor as needed and then lay 5/8" or 3/4" subfloor over that.
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