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Learned the hard way why you never trust a subfloor that looks dry but sounds hollow
I spent 3 hours last Thursday tearing out a perfect tile job in Columbus because the old plywood had delaminated underneath and I didn't tap-test it first so now I check every square foot before I lay anything.
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julia_anderson1mo ago
Done that dance before. Spent a whole weekend pulling up my own bathroom floor 'cause I got cocky and skipped the test. Felt like an idiot tapping each hollow spot after the fact. My wife still brings it up when I talk about starting a new project. "Remember the hollow floor fiasco?" she says. Yeah. I remember. Now I tap everything like a maniac looking for buried treasure only it's just rot I'm hunting.
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robert_bell1mo ago
Yeah I used to be one of those guys who thought tapping was just old timer superstition. Thought it was just a waste of time and you could spot rot by looking at it. Then I helped my buddy fix up his porch last summer and the whole thing looked fine from the top. Solid wood, good paint, no soft spots you could feel. But I tapped around just for fun and the sound changed right near the post. Pulled up a board and the whole joist underneath was basically dust. That changed my mind real quick. Now I tap every single board before I even bother with anything else. It's not exciting but it works.
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river_allen1mo ago
Read something once where a guy tested this with a stethoscope of all things... said you could hear the difference in wood density way before it even looked bad. Sounds ridiculous but after your story @robert_bell I'm starting to believe it. Might grab one next time I'm at the hardware store actually. Always thought tapping was enough but that takes it to another level.
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