Stabilizing concrete floor with plywood?

I'd appreciate informed opinions on the idea of using plywood sheeting to stabilize the fractured concrete floor in my apartment.
My apartment has a subfloor of 5/8" plywood overlaid with 1-1/2" of gypsum concrete (gypcrete). The gypcrete has lots of cracks which move and rub against each other, creating annoying crunching sounds when I walk on the floor. To eliminate the movement of the gypcrete pieces, I'm thinking of glueing sheets of 3/8" plywood with "No More Nails" to the floor.
I figure that the plywood will bind the gypcrete pieces, and that 3/8" plywood will be rigid enough to help reduce shear stresses on the glue, be flexible enough to conform to a floor that isn't perfectly flat and be thin enough to minimize the increase in height of the floor.
Any comments or suggestions?
Thanks in advance, Darro
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I would be very concerned about why things are cracking, theres a chance its a structural issue, have you reported it to your landlord?
you could remove the broken material, widen cracks and fill with cement patch.
this is another way to stabilize things but see your landlord first
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Do you own the apartment? If not, I'd say the landlord would be pretty P.O.'d at such an installation. Besides, repairs are his problem, in most cases. If you do own the apartment, and you already have it down to bare gypcrete, why not repair it properly? Bust out the loose parts, and have somebody come in and refloat the floor properly this time. If it didn't bond, they probably mixed it wrong, or the windows weren't in and it got rained on or froze or something. Is the building wood frame, or concrete and steel? If wood frame, there is plywood under the gypcrete firebreak, so replacing it with new floated floor (or even thin backer board) should not be a problem. Raising the floor is a PITA, and to be avoided.
aem sends...
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Darro wrote:

Good intentions, but a bad idea. I have dealt with hundreds of floors like yours. Unreinforced gypsum or lightweight concrete floors which have cracked and been reduced to rubble over time. I have spent hours and hours with different product representatives trying to come up with the perfect solution for these situations that is easy and inexpensive. I can tell you that there is no solution like that.
The least expensive repair is to remove the existing concrete and replace it.
The easiest solution is to use one of the many concrete repair products on the market which permeate and bond the pieces of your floor back together. These products will give you a uniform flat surface that is both durable and long lasting, but at a price.
I applaud you for your efforts to achieve a solution to this problem, but yours just will not work. The reasons why are too numerous to mention, but trust me, you would be wasting your time and money.
The removal and replacement option is obvious. For info on the other more expensive solutions, here are a few sites to look at:
http://www.chemrex.com/productCatalog/productListing.asp?catId7
http://www.chemrex.com/productCatalog/productListing.asp?catId4
http://classicsystems.net/specifications.pdf
--
Robert Allison
Rimshot, Inc.
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gypcrete that is cracked could be a sign of one or more issues. Poor installation/materials or worse a structural problem looking for a place to happen. Call the landlord and see what they will do. If yours is the only apartment in the place then maybe it is a materials issue. If yours is not the only one then it is time to get the paper and look for somewhere else to live.
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Darro wrote:

I think think your proposed repair MIGHT work but IMO it will be a lot of work.
Even a 3/8" floor thickness will require finish features to be modified.
take a look at the follwoing for ideas about DIY solutions http://www.ultraquietfloors.com/gypcrete_repair.asp
I assume the high traffic areas are the ones with the most compromised gypcrete.
IMO a liquid consolidation material (epoxy or urethane) is what will work best for you. Maybe you can try a small area & see if it works.
Water based materials will be more environmentally friendly (no fumes for you) but traditional "solvent" based epoxies are (IMO) stronger & more durable.
cheers Bob
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