DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Tiling, ceramics, marble (
-   -   ceramic thinset on slate (

jim85133 03-10-2013 02:37 PM

ceramic thinset on slate
I was doing a job with slate tile. The job is for my mantle and putting slate on my mantel. It worked great until i noticed that halfway through I mixed up the thinset I had and used the ceramic thinset on my slate.

What is the damage done here? Do I have to start over? Will everything start falling off? I am unsure how big of a deal this is.

JazMan 03-10-2013 06:18 PM

Why don't you just tell us what you used? Also need to know what kind of material you spread the thinset on to. So, you're doing the mantel, not the hearth?


jim85133 03-10-2013 07:24 PM

Ok. I purchased the thinset from home depot. It is prmixe, in a gallon bucket and simply says it is "thinset mortar for ceramic tile". They have a different premix that says it is for stone, pocelain and ceramic tile.

I used a slate tile onto a plywood backing. i cut the tile into 1.5" to 3" strips and "dry stacked" them on top of each other up the mantle wall. There will be no grout between them, the strips are stacked one on top of the other up the wall.

The bucket of thinset i used for the second half i used the thinset that says to only use for ceramic (and specifically states to not use it for stone tile).

Is that helpful? I can post a picture of the project and the bucket of premix if that is helpful.

JazMan 03-10-2013 08:10 PM

First of all, the pail you bought that says "thinset mortar" all over it, is NOT thinset mortar. They lied. Portland thinset mortar, by definition must be made from Portland Cement, there is no Portland in that bucket. Portland Cement can not be pre-mixed and stored. It'll get hard in a short time.

Will the slate fall off? Probably not. But it's a poor way to build a fireplace mantel/wall. It's probably against code and of course not fireproof or resistant. You also used plywood? Why?

I'd be thinking this over and maybe have my local building inspector or someone knowledgeable tan a look.

What did you mix up when you noticed it was the wrong stuff? You said;

It worked great until i noticed that halfway through I mixed up the thinset I had and used the ceramic thinset on my slate.

jim85133 03-10-2013 08:24 PM

First of all, thank you so much for your help and responses.

The hearth/mantel will only house a pellet stove. I can be within 2 inches of combustible material. It is a freestanding pellet stove so it mostly there for decoration.

I am mostly concerned it will fall off. I believe you are saying it shouldn't?

And it is good to know that I should stop using the premix and mix my own.

Thank you!

JazMan 03-10-2013 08:43 PM

One problem with mastic is that it's liable to stain some natural stones. I would bet that if the mastic was 'burned' into the substrate well, and the surface doesn't get too hot, you should be ok. Again, it's not right but may work for you.

When did you install these slate pieces? I'll bet the mastic is still soft and you could move the last piece if recently.

The recommendations and codes are there to not only protect you today, but when someone else buys your house and uses it in a different way. That zero clearance stove will not always be there.


All times are GMT -5. The time now is 11:25 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1