Material between finished floor & Subfloor???


Old 04-29-05, 07:13 AM
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Material between finished floor & Subfloor???

I need to replace the subfloor around my toilet due to a leak. When I removed the finished floor I found that I have a material between the finished floor and my subfloor. Both the finished floor and my subfloor are plywood. The best way I can describe what is in between is about 1/2" thick and the consistency of mushy cardboard (no it's not wet). When I try to remove it it is glued to the subfloor and shreads when I try to take it up little piece by little piece.

My first question, what is this material and what should I replace it with?

My second question, is there an easier way to remove it than scaping at it as it shreds? I am going to try a putty knife tonight to see if that is any easier but I am open to suggestion.

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Old 04-29-05, 03:04 PM
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It sounds like there's a sheet of hardboard masonite between your layers of plywood. It's pretty nasty stuff to get out when it's glued down. Almost as bad as the 1/2" particle board that I had to chip off a bathroom floor yesterday, which was glued down into a bed of tar. (don't ask)

I really don't think there is an easy way of doing it, unless you have an air chisel or rotary hammer with a wide chisel. I imagine that you'll end up chiseling the glue/paper off the plywood surface, and maybe have to sand the floor down with a belt sander w/ rough grit.

As far as what to replace it with, I'll let a floor guy answer that.
Old 05-01-05, 05:03 PM
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the tools

you might even try one of those big scrapers for removing roofing shingles....they look pritty aggressive.
Old 05-04-05, 07:51 PM
Join Date: Apr 2005
Posts: 42
hi red05 -

sounds like the stuff between your subfloor and finished floor is particleboard. over time, as that stuff absorbs moisture, it will swell up, rot, and ultimately shred - as you've found out. so even though it may not currently be wet, i'll bet that it had gotten wet - perhaps repeatedly - in the past.

i think you have the right idea of using a putty knife to remove it. my suggestion would be to use the widest putty knife you have to almost "shovel" it off the subfloor.

since it's in the bathroom, you might want to replace it with a plywood underlayment of the same thickness, instead of more particleboard. also be sure to caulk around the toilet, to stop any more water from entering.

hope this helps
Old 05-09-05, 10:00 PM
Join Date: Aug 2000
Location: USA
Posts: 15,834
I've removed particleboard in two rooms due to frozen kitchen pipes. No fun with a mattock and being a little old lady. Of course, I had no access to a rental place with pneumatic chisel. Then, disposal issues. I threw the waste into a burning pit, doused it with gasoline and ran, so I would not have to breathe the vapors. Of course, the property is in a very rural area in the middle of no where.

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