still learning the hard way

Norwiscutter · February 08, 2007, 11:53:32 PM

Well I started remodeling a bathroom in the house this week, and took it apon my self to do some tile work last night. Well we are trying to do things on a tight budget so I picked up some cheap 12x12 tile at the box store for .78/sq. ft., even though I knew better. (This tile is thinner than the more expensive stuff.) I also could not find the thin set in the store and I was in a hurry so I grabbed some mastic that said it was approved for floor tile installation. So I hurried home and did the install last night.
I have new backer board over a good subfloor so at least that is alright. Well I walked in there about an hour ago and sure enough, crack two tiles right off the bat. It has been 24 hours and I figured it would be good enough to walk on by now, seeing as it had been 65-70 degrees in there the whole time. So I pulled up one of the tiles and the mastic was still wet under the entire tile. The only place that had set up at all was on the tile edges near the grout lines.

So what should I do? Scrap the whole project and start over with thin set and better tile? Wait for the mastic to set up and see if it gets better, and if so replace the two broken tiles?
If I scrape it all off now is there a chance I can reuse the backer even though it has a coat of mastic on it?
Thanks in advance.

Furby · February 09, 2007, 12:00:43 AM

I'd drop two new tiles in right now while it's wet and then let it set for a couple days.

Norwiscutter · February 09, 2007, 12:02:39 AM

So you think the problem might not be the tiles themselves? They are a bit thinner than (5/16) on the edge, than some of the others I have scene.

TexasTimbers · February 09, 2007, 12:45:56 AM

Let it set. Replace the broken ones. Then you may have to scrap the whole thng. Mastic is notoriously prone to emulsifiaction in wet or humid applications. Never use it for shower tiles for example. To heck with what the insturctions say.
Thinset III is the way to go.
Mastic proponents remind me of plywood pushers. You can drop a piece of plywwod into a bucket and a piece of OSB and look at them the next day. the OSB will be the exact same size and not perforated. the plywood will already be swollen and seperating. Some old timers will still swear "I been usin plywood for 117 years jist fine....blah blah blah."

Well, off the rant. Try to stick with the mastic but don't be suprised if you have to rake it all out.

Furby · February 09, 2007, 12:59:32 AM

If the mastic was still wet, I belive it was a combination of things.
If you try to remove the broken one after it sets up, you'll probly break more trying to get the first out.
If you have two more and you can still do it, I'd replace them now.
If you don't have two more, at least remove the other broken one and scrape of as much of the mastic as you can before it sets.

TexasTimbers · February 09, 2007, 01:03:31 AM

I would say take a Roto Zip and score the grout lines deeply before removing the tiles but he hasn't grouted yet. Should be no reason other tiles would break. But yeah remove them anytime now or later. Just remove them and try to let it setup before scrapping the whole wretched mess eh.

DanG · February 09, 2007, 01:06:58 AM

Are we talking ceramic or vinyl tile here? There's a huge difference in the installation. ???

stumpy · February 09, 2007, 09:37:26 AM

I had something similar happen. I was told that 12 x 12 tiles are too big for mastic. They need tile morter or thinset (not sure of the names but i'd say concrete vs glue) I pulled all of mine up and scraped off the mastic and redid with thinset. No problem since.

rebocardo · February 09, 2007, 10:44:05 AM

> So what should I do? Scrap the whole project and start over with thin set and better tile?

Yes, that is what I would do. Anything 8x8 or over requires much thicker and different cement and a different spaced trowel too. You really need 1/2" cement board behind it too unless installing over slab because most floors deflect too much. Plus, it takes forever to dry.

The other thing is 12x12 cracks really easy. I avoid even 8" and stick to a thick 4" because if a customer wants a cracked tile replaced it is not that easy. Plus, it dries better and goes much faster with a fan on.

jackpine · February 09, 2007, 11:21:19 AM

Norwiscutter & Rebocardo

Now you have me worried >:( I just tiled my main bath yesterday afternoon with 12" tiles. Have not walked on them yet as instructions on thinset ( did use thinset and ½"cement board) say to wait 16 to 24 hrs. I guess i'll know later today if there is a problem with cracking tiles.I tried to talk the wife out of 12" tiles with no luck ;D

TexasTimbers · February 09, 2007, 11:51:01 AM

jackpine I think you'll be okay. You used thinset not mastic 12" or not I think you'll be fine.

Only time I use mastic is when I am installing hardwood floor over concrete slab.

Norwiscutter · February 09, 2007, 11:59:08 AM

Thanks guys for the help. I think the combination of small things has resulted in one large problem. I used 1/2 inch backer over 3/4 osb with 16inch centered firing strips, so the subfloor should be alright. At this point I think I am going to leave it and see what happens, although I have it set in my mind that I will end up redoing it the right way. I think that if I had gone with a thicker tile (3/8) they might not have broken. This is always what happens when you try and save a few bucks :-[ That being said, in a bathroom with little traffic, it might work out for a while.

Engineer · February 09, 2007, 03:00:43 PM

Been asking myself all kinds of questions about tile, since I have been doing four bathrooms and my kitchen in various types of tile, driving myself nuts basically. First, like you haven't heard it already, you need to use thinset, preferably a latex-modified thinset. Mastic is good for about nothing. I am putting all my tiles down with Laticrete thinset and a latex additive, also Laticrete. No water. It's like adding heavy cream to cement powder. My whole kitchen is 12x12 gauged slate, and so I need to make sure that it's not going to move at all. The thinset, when latex is added, becomes somewhat flexible, but not enough to allow the tiles to crack. Even a thin tile should be fine on top of the right subfloor and thinset. I have 12x12 cheap Home Depot tiles in my bathroom at our old house, they were set over 1/4" backerboard and thinset and are just fine. All the rest of the tiles are either small ceramic tiles or 4" square stone tiles, so I don't worry about them as much.

Don_Papenburg · February 09, 2007, 06:43:31 PM

Check out the John Bridge Forum . It is where you will get tile advice from the pros. They will tell you to use only thinset on floors . I concour with them . It dries /hardens faster gives a cushion so to speak to the tile as it compensates for low and high spots . Mastic does not have the thickness to do that. My opinion would be cut your losses now rip up all the tile and clean up them and the floor before it dries . Then go get thinset and you will be a happy camper.