Concrete 'curling' in corners ff. wet installation

Ann K. Williams

We are remodeling and adding to a 1935 bungalow in the Western
Mountains of Maine. In the new part, which is a 30 ft. X 20 ft. area, the heating engineer installed a hydronic radiant heating system, with a wet installation layer of lightweight concrete over PEX tubing, which had a layer of poly laid on top of the tubing (and under the concrete). The concrete was poured in early Dec., and is now 'curling up' at several
corners, such that it visibly (and audibly) moves when someone stands on it. Since we intend to have ceramic tile laid on the concrete in one area, and engineered (K

Ann K. Williams

Correction...

In the layout, the poly was laid on the plywood subfloor, then the tubing, then the concrete (not the initial way I described it, with the poly on top of the tubing...). Apologies.

Bruce_6

slip sheets

or poly sheeting should never be installed for a lightweight pour. the lightweight needs to adhere to the subfloor. usually they spray a chemical down befroe they pour it, this helps the lightweight "stick" to the subfloor.

the problem is in the installation, you may not have any choice but to have the lightweight removed, remove the slipsheet (poly)and have the lightweight re-poured.

Mad Dog

Sounds like Trouble Ann....

you need to get a real radiant pro out there to evaluate things. Try find a professional.. I went out on 2 botch-radiant jobs this week installed by radiant "experts". Mad Dog

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Mark Hunt

I agree with Bruce


The gyp needs to adhere to the sub-floor.

Mark H

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steve gates

didn't he say

concrete. Gyp no slip concrete yes. Lavarock?

Mark Hunt

Yup


Re-read it.

Mark H

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Ann K. Williams

Is There A Way...

to get around this short of removing the whole floor? I really appreciate everyone's help on this, although I don't like to hear it. Thanks again. Ann

Mad Dog

I really don't know...have to see it...

that is whY I recommend a real Radiant Pro from this site to consult on it..before you waste more time and $$$$$. I just came back from a job where the folks spent $5,000.00 on staple up radiant that is all wrong and must be ripped out. what a shame. Mad Dog

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Mike T., Swampeast MO

If my imagination is correct...

"seeing" a thin fairly rigid slab over but not attached to a [wood frame?] substrate...

I believe the corners in particular would appear to "rise" if the middle sank. Even "lightweight" concrete is quite heavy and the flooring system must be able to deal with the load.

I think I'd consult with a structural engineer or good architect to ensure that ANY such thing is not doomed to failure without structural reinforcement.

hr

Clear us up

is this a gyp pour or a concrete pour. If it has aggreate of any type, it's probably a concrete mix. If so, yes a poly sheet needr to be laid to prevent the concrete from sticking to the subfloor, and also preventing the plywood from sucking the water from the mix and upsetting the cure.

Find out exactly what was used for the pour. Generally 1-1/2 thies the aggreate diameter is needed over the tube.

If 1/2" diameter tube was used then 1/2 or 3/4" roch would be max.

Wonder if the aggreate used was or has frozen??

hot rod

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hr

Don't panic

the company that sent the mix should be consulted. It sounds to me like a redi mix job, not Gypcrete.

Gypcrete is not a true lightweight product. TRUE lightweight concrete used styrofoam or pourus aggreate to "lighten" the weight. This would have been mixed locally.

Most batch plants will send a troubleshooter out to see what is going on. They have been know to replace the product, if the failure was on their part.

We need some more info.

hot rod

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