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Plywood sub floor in bathroom-dry rot or delaminating?

4K views 3 replies 2 participants last post by  joecaption 
#1 ·
Our toilet tank leaked so we replaced it. We had to tear out the 40 year old carpet (I know, ick) and the underlayment particle board. We are left with the plywood sub floor. One spot, out in the middle, where no water was standing, is a spot that feels bouncy and super dry and appears to be delaminated. I can poke my nail in it but have been forbidding to do the screwdriver test. My husbands friend (a contractor) who has not seen it told him it isn't dry rot and just to go ahead and cover it with the new underlayment. I think this is bad advice. I did climb into the crawl space and pulled back the insulation and couldn't see anything from the underside (and I snuck a screwdriver down there with me to check) should I just not worry or should I get some wood glue and inject it into the questionable area and weight it down? My husband has never undertaken *any* home repairs and I have a pretty extensive do it myself background, but because I am a girl he won't listen to me.
 
#2 ·
Had to say without being there to see it.
Could be CDX plywood that's full of voids and knot holes in the core.
It should have been subfloor rated plywood or better yet Advantec in my opion.
Unless he's willing to remove the subflooring and start from scratch, it would be best to go over the whole floor with new 1/2" subfloor rated plywood making sure to not have the seams line up with the seams below and fasten ever 4" on the edges, and every 6 to 8" in the field.
Advantec is far more water resitant.
I also would not suggest any type of wood (or grass as in the case of Bamboo) to any of my customers for flooring in a bathroom.
 
#3 ·
Thank you, I will check in to Advantec. Our condo was built in 1972 and I am quite confident they used the cheapest materials known to man to build this place so I doubt they used any high grade subfloor or anything else. I also know he has no desire to attempt the removal and replacement of the entire subfloor. I also liked your added comment re flooring types. You would then agree with me in that his choice of cork as a bathroom floor is a horrible idea!
 
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