Hydraflex usage - cracks vs full slab - Garage Tile

[theeld]

Will be tiling garage floor slab in (approx 1000 sq ft) in next few weeks. Contractor is a TEC user such that Hydraflex will be used at a minimum on control joints/cracks. I am considering treating entire floor with Hydraflex at of course increased cost. Soliciting opinions with some amount justification/rationale behind as to benefits of treating entire floor. Tile is 24x24 rectified porcelain, will be using epoxy grout from spectralock ("pro" I believe), at my personal request.

Supposedly will run me an extra $2500 for treating entire floor instead of just obvious areas/cracks, etc.

I do wash cars in my garage frequently. Trench drain along 2-stall door rear, as such has adequate slope. 3rd stall is "more" flat, very gradual slope. Garage floor does not have vapor barrier below slab, is on mostly sandy ground. In Iowa so temperature swings with "moderately cold" winters.

Thanks guys/gals!

[cx]

Welcome back, Lyle.

You'll wanna read the instructions for use of that crack isolation product very carefully, including the Technical Bulletin referred to in their general instructions.

There you'll find that their Crack Isolation product (ANSI A118.12) requires the same treatment as all other such products of which I'm aware. That is, to apply the product a minimum of three tile widths centered over a crack or control joint and provide soft joints in the tile installation on both sides of the joint. Once you've properly applied the membrane over the known joints or cracks, it's probably not as much of an additional cost to cover the entire floor.

And the application of the product is likely to be a bit problematic, too. You'll find it difficult to apply the required two coats of a minimum 25 wet mills thickness. It's a lot of product and not at all simple to achieve. But the product depends upon the thickness of the cured material to achieve the advertised crack isolation.

And if any of your cracks has any height differential between one side and the other, no crack isolation product will pretend to give you any protection at all.

I would strongly recommend you do at least a rudimentary moisture vapor emissions rate (MVER) test on your slab before you proceed. I don't know what the limit is for the TEC product and I didn't see it in their literature, but if you've got substantial moisture vapor, you'll want to contact their tech support people and at least discuss the issue.

My opinion; worth price charged.

[theeld]

Appreciate the advice and perspective, likely will follow up with a test as you describe! Imagine if water/moisture escape is “high”, that would be rational for waterproofing fully before laying tile.

[e3]

If the water vapor transmission rate is too high you may find that a liquid applied membrane will not properly bond to the substrate. Kind of like trying to paint a wet wall it just doesn’t stick.

[cx]

Nope.

What Eric said.

[theeld]

Thanks guys, makes good sense, will likely have clarity on vapor escape test in short term.