Flooring Tile - Slate on Slab question

Hi, quick questions for below grade tile install on slab,

Do I pour SLC on the slab first, then use redgard, or redgard than SLC?

Will be using 12x slate, any recs for thinset and sealer are appreciated. guess i should do 1/8" grout lines.

thanks!!

What are the reasons for the SLC and redgard?

I would rather use Schluter Ditra for the underlayment, then tile

or

If your slab has cracks (flat) I would use a Noble CIS underlayment.

What type of slate?

Put the piece of slate in a bucket of water over night. The next day, take it out and wipe it down with a towel. If your towel gets colored, it is cheap slate and will fall apart over time.

You can use a good modified thinset, like Flexbond, and a good presealer/sealer like 511 Impregnator.

Thanks for the reply.

The reason for the redgard is that I have 4 gallons in my possession already, I want to waterproof/seal the slab (directions say 2 coats does it), and since it is only a month old cracks may form from stress points that aren't there now, i see some tiny hairlines a few inches long in some of the outer corners starting, so redgard is isolation membrane. Also, painting redgard is easier than ditra, but obviously not as effective.

The reason for the leveling compound is because there is a slight grade upwards were the slab meets the poured concrete wall (1/4" at it's worst, mostly less than 1/8" over one or two feet or so..)

Thanks for the tip on the slate. I found cheap stuff at HD for $1.5/sq ft., so I'll pick up one tile and test before i buy the 250 sq ft. i need.

Are you saying that this is a brand new slab? Why are you wanting to waterproof the slab, are there some water issues here? If so, redgard won't fix that.

I found cheap stuff at HD for $1.5/sq ft.

Good luck with that Indian slate at that price. That stuff wouldn't be bad if they left it in the ground another million years or so.

I can't tell you the truth about it cuz I'd get suspended again.:wall:

Jaz

This slate from HD says from China, does that have a bad reputation as well? Can't hurt to do the bucket test.

I am using redgard as an isolation membrane in the case of future cracks. I do not have a water problem, but coating the slab will help reduce ambient humidity in the air.

But anyways, about whether to paint it on top of the leveling compound?

Well, the Chinese slate might be worse? Look, it is selling retail for a buck fifty, it is not good stuff.

It costs about 60-70 cents to get it to the USA. Then there is 8% duty plus brokers fees and transportation to the HD warehouses. They have to store it and ship it to each store, and make a profit.

If you want good slate, get Vermont Slate from a reputable tile shop.

Jaz

With slate, you get what you pay for. If you use this HD slate you'll likely be sorry you did in short order. I agree with Jazman 100%.