EZ Flow self leveling underlayment cracking

Did you compact dirt/gravel before pouring? I think you have a settling problem under the slab. You might have to do over, or same may happen again.

First off, I've used self levelling before with varying results but never cracking. Did you use the proper bonding agent (ie. it appears to be some sort of epoxy binder that you paint onto the floor)? I also seem to remember that you have to clean the slab of paint and such for this to bond properly. Cheers, cc

Yeah, I didn't read original post carefully enough- thought he was pouring slab on to dirt.

see also:

Thanks for the responses. First, no I didn't use a bonding agent/primer, since, reading the instructions on the bag, they made reference to the fact that it was sueful in avoiding pinholes in the finished surface, not that it was necessary to prevent cracks. Having read a bunch of stuff last night, I realize that was a mistake (expensive too). They also don't make any reference anywhere (website, instructions on bag, etc. ) to paint being an issue (ouch again). I was thinking of laying down a layer of kerdi or embedding a plastic or wire mesh into any new layer. Any thoughts on that?

Kerdi is Schlutter's waterproofing membrane, Ditra is their uncoupling & waterproofing membrane.

- embed 1/4" Hardie backerboard in thinset.

- use an isolation membrane. The manufacturer will specify the size of crack it will bridge.

- fill the cracks with a pourable two part epoxy such as Git Rot.

- take a flyer that the stuff won't move anymore and that the thinset will fill the cracks.

Well, thanks to all who responded. I'm resigned to the fact that I'm ripping it all out. I've also looked at different products and options and I think that I'm going with Mapei Ultraplan1 and UltraPrime L primer and, as per their instructions, grinding the paint off the surface with a diamond grinder (hopefully HD or Rona have those available for rental). One thing I like about this product is that they make it clear what has to be done before the product can be applied, as opposed to the EZ Flow product, which didn't say either way that it shouldn't be applied over a painted surface.

I'll let you all know how it went.

Joel