Tile contractor wants to use mastic for wall tile

We are getting our bathroom tiled on the floor and about half way up the walls. There is no shower, but the bath faucet and hand sprayer are in a three foot kneewall at the end of the bathtub. A tile contractor who was recommended to me took a look at it and he said he would use mastic on the walls if he does the job. I've read here that mastic is not a good choice. I've read since mastic is organic, it's more likely to get mold and/or mildew and it is more likely to fail in a few years. The tile contractor says he prefers mastic because it is stickier and will hold the wall tiles better while he sets them. This tile contractor has 10 years experience and he has good references. I'd like to hire him, but I'm concerned about his preference to use mastic over thinset. I hate to tell him he has to use thinset because if he's not experienced at using thinset for wall tiles, the tiles might slide down and he might say that it's my fault for making him use thinset. What should I do? By the way, he says he has no problem using the Laticrete Megabond thinset (I've already bought) on the floor tile. However, he does not think it's necessary to use the Laticrete Megabond additive and says mixing the thinset with water will be just fine.

What size tile and type are you using on the walls, mastic is fine for 8" or smaller ceramic, if a customer wants thinset, I'll use it, spacers are used on walls with either method and shouldn't have any effect as to tiles sliding or any issue with that.

As for the floor thinset, never used that, but if it's a modified thinset, no need for any additives, just use water.

Best solution--buy him some "non-sag" thin set like Tec 3N1 or something similar for the walls.

He's only got 10 years experience, no wonder he doesn't know how.

If I remember, Mega is a dry-set, non modified thinset. We need to confirm that and you need to tell us what kind of floor you have.

Jaz

Ten years and doesn't know how to use thinset on the walls?

There's something wrong with that! Tell him the tiles won't slide if spacers are used. Does he want to grout it the same day also?

I'd look around for a more experienced tile guy I think.

Megabond IS a dryset, the Lowes version of 317

Thanks for the replies. I plan to use 12" porcelain tiles on the floor. The Laticrete Megabond thinset says to use the Megabond Additive for best results. So I guess it is unmodified when used by itself. Here are pics of both products:


Here's the additive

The wall tiles are 3" with 12 tiles in a 12" sheet. We want to use a 4" accent tile with a glass insert. Here's a picture of the same tiles on display.

Here are pics of the mastic the tile contractor said would be best:



Lowes sell all of the materials above and they are the only source locally for tile and supplies.

Do you believe the mastic pictured above will work okay in this application? Any and all suggestions will be appreciated.

Get one of their Modified Thinsets, perhaps you can get a discount if he is going to learn on your time. I doubt he has not done TS on the wall in 10 years. If in fact he has not, find another contractor.

You can use Mega with the additive or why not just buy the multipurpose thinset they stock? You need one or the other with porcelain regardless of the substrate, which we still don't know what it is.

If your tile 'guy' wants to use mastic for the walls because of less slippage, I wouldn't have a big problem as long as it's a dry area. It sounds like your project is a dry install only. However. I'm pretty sure you shouldn't use that mastic if there is glass tile involved. Sounds like he doesn't care about that much.

I don't have as much confidence in your tile guy as you seem to. Maybe cheap price?

Jaz

It's not that his price is cheap. It's hard to find good time contractors where I'm at in eastern NC. I wish I could hire one of you guys. The substrate is Hardiboard CBU for the floors and the walls. While the majority of the area will be dry, I am a little concerned about the area around the bath faucet on the kneewall and along the edges of the tub. Cheap masonite-like tileboard was installed there before and it just fell apart from the moisture. So I know this area gets some water. Of course it's nothing like what a shower would get. Perhaps a compromise would be to use thinset on this area only.

In reply other posts, I suspect this tile contractor probably knows how to use thinset on walls. I think he wants to use mastic because it is easier and faster to work with. He swears that mastic is good stuff. Maybe he doesn't know, or is it possible that mastic has improved over the years and that modern day mastic no longer has the downfalls of the mastic of yesteryear?

Just the opposite in my thinking. The older mastics were good until the Fed's removed the V. O. C.'s. The newer mastics leave a little to be desired. In dry areas with smaller tiles it's OK. I don't think you want to use mastic with any glass tiles, better check into that and let the glass tile supplier spec the adhesive. Using thinset isn't near as handy as using mastic, I'm sure that's his whole complaint.

Pop the lid and off you go. When you want to go home plop the trowel in a bucket of water and worry about it tomorrow.

Just the opposite in many cases. Years ago many mastics were solvent based and actually work fairly well. When they got wet, solvent mastic did not re-emulsify like many of today's mastic do.

Mastic is always a bad choice in damp or wet areas on walls, and for all applications on floors.

It's not as good and costs many times more to boot.

Where in NC? Maybe we can find you someone else?

Jaz

YIKES! Both of this forum's smart asses start their answers the same way.

Jaz

I'm in New Bern. It's about two hours east of Raleigh and about an hour from the coast. I'm curious to know what the problem is with mastic and glass tiles. It's hard to imagine that this mastic can't hold those little glass tiles.

It's not a question of the mastic holding the glass tiles, it's that mastic might telegraph through the glass tiles. I myself am a convert from mastic. I only use thinset now, unless on a backsplash. It is much more economical to use thinset. Literally half price.

Do what you want Steve you have our blessings.

Mastic won't stick to glass by the way.

Call DAl Tile im Wilmington. They will have some info on contractors in your area.

Thanks for all of the help. Jazz and Bud, you are correct about not using mastic with glass tiles. I called the toll free number on the side of the mastic bucket and their tech support said it is NOT recommended for glass tiles. They said it may not adhere properly to glass. The don't even recommend it for these little 2" tile inserts. Suprisingly, they said their mastic is fine to use for shower walls. But they said not to use it on shower floors or anywhere water might be standing. However, just to be safe, if I use this contractor, I think I'll also insist that mastic not be used on the kneewall side where the faucet and knobs are.

Jazz and Bud, you are correct about not using mastic with glass tiles.

Yow, we know.

I think I'll also insist that mastic not be used on the knee-wall side where the faucet and knobs are.

Good idea! I'm thinking maybe you should interview a few more installers before you go ahead with this guy.

Surprisingly, they said their mastic is fine to use for shower walls. But they said not to use it on shower floors or anywhere water might be standing.

Their above statement tells you what they know about mastic in wet areas. How would you keep the bottom row of tiles from getting real wet? How wet is too wet?

Sorry to say this. but. Most adhesive manufacturers have a slipght problem with telling the truth when it comes to mastics and pre-mixed anything.

Jaz