Concrete topping - tough and rigid?

[Darro]

I have a section of concrete floor (1-1/2" thick x 60 square feet) that is fragmented and deflects slightly when I walk on it because the

5/8" plywood subfloor was inadequately fastened to the joists. To stabilize the concrete, I'm thinking about applying a topping on it, ideally no more than 3/8" but thicker if necessary. Can anyone recommend a topping that's trowleable, thin, crack-resistant/crack-proof and rigid enough to resist deflection from foot traffic? Thanks...

[dpb]

Sure, it's called pure unobtainium...

Actually, probably about the only thing that would do the trick given those underlying specifications would be 3/8" steel plate.

--

[Ed Pawlowski]

There is none. Can you support the weak section from underneath? Fasten through the existing concrete?

[hallerb]

rip out existing and replace. anything else will fail probably sooner rather than later.

so why do you have a concrete floor over plywood?

[aemeijers]

Probably firebreak. Pretty common in cheap apartment buildings.

-- aem sends...

[Red Green]

dpb wrote in news:gd6184$r0r$ [e-mail]:

Looks like I need an updated periodic table.

[BobK207]

I'm guessing you've got a deteriorated gypcrete situation.....you "might" be able repair / re-consolidate the fractured crap with a liquid 2 part epoxy like SIKA Sikadur 35 HI-MOD, LV, LPL.

The stuff ain't cheap, comes in a 3 gal "kit".... total 3 gallon kits yields about 700 cubic inches of mixed resin.

I'm not sure how you'd calculate or estimate how much you'd need to do the job but a full kit would give you about 6 ozs per sq ft......

maybe enough re-wet all the cracked pieces & glue them back together?

For my money I'd remove all of it, screw down the plywood & re-pour a new batch. A successful repair would be a long shot.

cheers Bob