Subfloor/Underlayment, engineered hardwood, tile, etc...

Old 10-17-13, 03:11 PM
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Subfloor/Underlayment, engineered hardwood, tile, etc...

I have read many threads on here which are oh so similar to the situation I find myself in. I apologize for starting yet one more thread, but, I'm not absolutely certain any of the answers I've read are for the precise situation I have before me.

1970's home, 1/2" CDX plywood subfloor on 2x10 joists, 10' max span. On top of that _was_ particleboard and carpet. Both of those are gone, we're down to the plywood subfloor and felt paper.

The joists and everything structural up to that point are very solid. The plywood is in very bad shape in many areas though. 1/4" or more deflection when I step on it between joists. We started installing bridging between joists around 24" apart and there is still noticeable deflection between those. Stopped at that point to think about things...

We want tile in the kitchen and hardwood most other rooms. We have the 1/2" x 5" engineered hardwood already. Aesthetically the hardwood will look better installed parallel to the joists.

If I just pretend like the subfloor isn't there, and install Advantech 23/32 T&G over it, will there be any problem with the hardwood installed (stapled) directly to that, parallel to the joists? What about 5/8" OSB instead, again parallel to the joists. The high traffic areas we'll have bridging between joists but not every single spot where the subfloor is less than ideal most likely.

The current thinking is to totally remove the 1/2" plywood subfloor in the kitchen area, glue/screw Advantech to the joists, then add probably 3/8" AC plywood and {appropriate thickness} backerboard to bring the finished tile height up to the finished hardwood level.

Are we on the right track? Any suggestions or pointers? Ripping the entire home down to the joists would be hard to swallow but short of that, I'm game.

Old 10-17-13, 03:38 PM
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A 1/2" subfloor was common in the 70's. No clue what there thinking was except to save money.
It's useless as a subfloor.
Going over it in my option just asks like a 1/2 shim under the proper subflooring and can cause squeaks. It's done all the time but I just refuse to do it and always remove the 1/2. I cut out the outside edges with a Toe Kick saw and a sawsall.
CDX is full of voids in the core, far batter to use Advantech.

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