TEC Universal Mastic? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : TEC Universal Mastic?

12-11-2016, 10:26 AM
I'm a rookie.
I've completed a few small jobs. To me, mixing the mortar properly and the pressure of it setting as I use it is the worst.

The reason for my post is that I stumbled over this TEC Premium Tile Adhesive Universal Mastic. Two guys separately in the big blue box told me that it would be fine for my needs. Although the pail recommends it for tiles 20x20 max and trowel 1/4x3/8x1/4....

I'm getting ready to start tiling a mudroom and adjoining half bathroom, total size is 7' by 33'.
I have the 1/4" Hardibacker down.
I am using 8" by 48" tiles (fake wood look)
1/8" grout lines
Using 1/2" square trowel
I have already purchased TEC Large Tile Mortar Latex-Modified Mortar

1) Would it be a huge mistake using the mastic product for this job?
2) If not the mastic, is the latex-modified correct?
3) Is 1/2" square trowel the proper size?
Any other tips are greatly appreciated!
Thank you!!!!

Sponsored Links

12-11-2016, 10:34 AM
Welcome back, Scott. :)

1. Yes, very large. Using it over Hardiebacker will help with the drying, but I wouldn't recommend it for that application.

2. Yes.

3. Depends upon the flatness of your tiles and your substrate. The tile industry standard for flatness of the floor for tiles that size is no deviation from intended plane of more than 1/8th-inch in ten feet nor 1/16th-inch in two feet. That's a very flat floor and it's unlikely you have that unless you took some specific measures to make it so.

My opinion; worth price charged.

Tool Guy - Kg
12-11-2016, 10:39 AM
Hi, Scott.

I don't think there's a pro on this forum that would give you an ok. Perhaps if you had a very absorbent substrate and tile...and you gave it a long time to dry out....and the tiles were smaller. But you don't. That 1/2" notched trowel (may be the right size, depending on flatness of substrate & tile, but you'll have to test) is going to lay down a thick layer of mastic and won't dry out soon...
...in short, you'd be asking for problems.

First, let's talk about mixing mortar. If mixed with the proper amount of water or admixture, a paddle & drill (the type and speed matter), allowed to slake, and mixed again, it becomes easier to mix. And there are mortars that will yield 3+ hours of pot life. As long as you don't add more water, you can use the paddle to twist the mortar in the bucket up to loosen it up a hour or two or three down the road.

Are you mixing by hand?
Is there mortar under the Hardibacker board?
Do you have alkali-resistant mesh tape to tape all the Hardibacker seams?


12-11-2016, 10:41 AM
Go back to the blue box store and tell them to read directions on the products they sell.

Use the Tec mortar with the 1/2" trowel.

You did use thinset under the Hardibacker right? :scratch:

12-11-2016, 10:44 AM
It will be a huge mistake and you don't want to find out which problems will happen at a later time .

I will highlight a limitation from the literature of the product :

Not for use for leveling or in excess of trowel recommendations.

One pointer -- not to exceed the notch 1/4x3/8x14 -- is sufficient to guide you in going with the mortar product for your floors and large tile installation . In your application , the full coverage and use of an appropriate trowel to achieve it , is out of the range of the intended use of the mastic .

12-11-2016, 10:48 AM
Thank you gentlemen....

Yes, I used the proper tape, and used the thinset under the hardibacker and smoothed the tape down with it.

Thank you for the tip on mixing; I have always mixed by hand, but I'll buy a paddle and a big drill to mix it from now on.

Thanks again. If you weren't here I would have used the Mastic.... I had already bought it.

Tool Guy - Kg
12-11-2016, 11:00 AM
You need a slow speed mixer. Mixing too fast mixes in air and that's a bad thing.

Also, get an egg-beater style of mixer from the tile and mortar aisle. Stay away from drywall mud mixers.

This is going to make your experience with thinset quite a bit easier than you're used to. And your pot life is going to increase. I'd suggest going out of your way to measure the quantities of water and powder so that you get consistent results.


12-11-2016, 11:06 AM
Good luck my neighbor down the 90!
Using the proper paddle and following the mixing directions will make a huge difference in you're tile experience! :D

12-11-2016, 02:45 PM
Since the average DIY'er normally can't mix a full bag of mortar and use it all before it starts to set in the bucket, you're stuck with mixing smaller batches. Because the consistency of the mortar changes as you mix then let it slake and then remix, it's sometimes tough to eyeball it and get the same result the way it was designed. So, I suggest that you use something like a bathroom scale (or maybe a larger kitchen one, but many of them do not go all that high) to proportion your powder and carefully measure your water out. You might then find you want to slightly alter the mix with a little more water or powder, but you'll be consistent batch-batch. For example, say that the 50# bag calls for 5qts of water, it's pretty simple to say if you want to mix 20#, you'd also measure out 2qts. The scale I use reads out to 0.1#, so it's pretty easy to be pretty precise and then less than a cup of water for fine adjustment.

While mixing it by hand can work, it's much tougher the larger the batch, and a modified thinset is even tougher to mix thoroughly by hand. You need to wet all of the particles, then mix it well to coat the cement with the modifier evenly...hard to do by hand. It's really important to mix at the speed and duration called for in the instructions...don't shortchange it...the difference can be dramatic.