Questions on thinslab radiant (uneven pour)

Jerry Fountain_2

We just had the slab poured over the radiant tubing (1/2" AlumiPex) in our second floor bathrooms. The material was Thermofloor, aka, gypcrete. The slab set up well, but there was some uneveness with a few seeming valleys of between 1/8" and possibly 1/4". At 1/8" I would think the mortar bed for the tile could even out the irregularities, but I'm a bit concerned it might be too much. Does anyone handle these much? Can a floor leveling compound be used (i.e., fairly runny stuff that self levels)? If so, is there a limit of how thin it can be? We will be installing a waterproof & anti-crack membrane before the tile so I was wondering if it would be recommended to put any leveling compound down BEFORE or AFTER the membrane? Any prep needed if the leveling compound goes down right on the gypcrete to ensure a good bond?

Thanks for your input!

Jerry

Rock Solid Restoration_3

The only thing that I can think of that would go down that thin and not crack and that would self-level if mixed at the right consistency would be epoxy.

As far as the compatibility with the gyp-crete you should speak to your thermafloor installer. Better yet, ask them if they fix the problem for you since I'm sure they told you it would be ready for tile when they were done.

What type of waterproofing membrane will you be using? Will that be compatible with the thermafloor or whatever you use to level it?

As far as the preparation, whenever I install epoxy or waterproofing to a concrete surface, even if it is brand new, I always sandlast or shotblast it first.

I do work on parking garages, however, and I know that this may not be practical in a bathroom. The preparation of the surface is extremely important when you are talking about a thin overlay. If you skip this step, you will not have a bond.

Can you post a picture of your situation?