Can i get away with 1/2" plywood over a slab?


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Old 01-07-15, 08:58 AM
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Can i get away with 1/2" plywood over a slab?

Hi all,

80% of my house is raised with 3/4" plywood sub-floors, i've already installed 3/" red oak in these areas and it came out great.

Now we're to the part of the house that's a little bit of a head scratchier. We have a sunken den that also has a bedroom connected to it, both are on slab. When we bought all of our flooring months ago we decided to pick out 3/8" red oak for these room because we knew we'd have transition issues with it being on a slab.

Originally we had planned to do a glue down, but after doing more research I think i'd rather lay down plywood and just go with good ole nail down instead.

My question though is if I can reasonably get away with going with 1/2" plywood instead of 3/4"? It would just make me feel a lot better about all of the transitions we're going to have. With the flooring being 3/8" I could go with a 1" cleat and i'm pretty sure I'd clear.

Just wondering if this is a terrible idea or not.
 
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Old 01-07-15, 09:18 AM
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I don't think 1/2" would be enough for nailing the floor down and I'm not even sure you can nail a 3/8" thick floor. If you can nail you'll be going through the tongue so the nail will only be in about 3/16" of the flooring and rest into your subfloor.
 
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Old 01-07-15, 12:00 PM
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Does your floor list a floating option with the 3/8" you purchased, a glue to each other floating floor would be your easiest solution.

Here is a handy chart on various profiles and cleat penetration.

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Old 01-07-15, 12:13 PM
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I don't think I would advocate laying plywood on any slab due to possible moisture problems.
 
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Old 01-07-15, 12:32 PM
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I would think plywood on the slab would have to be PT and I can't even begin to imagine how much that would warp.
 
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Old 01-08-15, 10:13 AM
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The plan was to lay a sheet of poly under the plywood and then screw it down into the slab with tapcons, similar to how you'd lay down a subfloor on florr joist.
 
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Old 01-08-15, 12:01 PM
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What good would the poly do with a kazillion holes in it? Sort of defeating the purpose, don't you think?
 
 

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