Hardibacker and too wet thinset?

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Old 02-25-10, 09:17 AM
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Hardibacker and too wet thinset?

So happy to have found this forum! I need help.

My husband and I are installing tile for the first time and while I was out last night he thought he would be proactive and started installing the hardibacker over our plywood subfloor. (We have a 1969 house with planks over the joists, then we installed plywood with piles of liquid nails and screws, and now are on to backer.) Anyway, he had already installed three whole boards when I got home and realized he was mixing the thinset too wet. At least as far as I could tell. Not horrible, but it was definately looser than say a mayonaissey consistency. We are using a 1/4x1/4 square trowel. I think he was doing a good job getting even coverage and straight trowel marks.

Is this going to be a problem? I'm just having nightmares of it never drying or growing mold or something.
 
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Old 02-25-10, 11:45 AM
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Hi Artchick,

No way for me to know just how soupy he mixed it, but it shouldn't cause any problems since its only there to fill voids. Thin set for this purpose is mixed a little looser than for tile setting. However once troweled, the thin set should still hold its ridges.

BTW, next time you install underlayment do not use adhesive, esp. glues that come in a tube.

What specific type of tile and what will you set it with? Tile size, trowel notch size? Did you consult a span chart to make sure the framing is stiff enough? How thick are those planks? What grade and thickness is that plywood you installed?

Jaz
 
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Old 02-25-10, 12:00 PM
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Thanks Jaz! Yea, it wasn't really soupy, it was holding the trowel marks without running into itself or folding over, I just thought it looked wetter than the demonstration I saw at our local tile shop for the backerboard installation. Makes me feel better

As far as the adhesive... I was told by several different installers and the tile shop that I needed to use liquid nails between the floor slats and the plywood? If you have a different suggestion I would love to know what you think because although it's too late with this project (I would probably sell my house before tearing it up !) we will be doing an entry and bathroom next.

Tile: 18" porcelean
Mortar: Planning on setting it with the same thinset as we have been using on the backer only thicker (like peanut butter I've been told). I think the brand is Verabond or something like that.
Trowel: We got a 3/8x1/4 square trowel for setting the tile and were told to wipe some over the tile too to make sure we got good full coverage.
Span Chart: I guess I didn't because I'm not sure what it is but I had a tile installer come to the house to look and said we would be ok. The planks are installed on the diagonal, pretty tight together and are 3/4". We reinforced a few placed with 2/4's that seemed wiggly. Then we installed a 3/8" good quality plywood. This is where we liquid nailed and then used screws every 4" along the studs and about every 6 inches everywhere else. We were hoping for a 1/2" but we were running into problems because I would't have been able to get my dishwasher in or out without uninstalling and reinstalling all my cabinets. Also, it would have left a gigantic level difference between that and our living room hardwood. Then we moved on to thinset and backer. Hence the thinset scare.

Are we on the right track?
Thanks a million!
 
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Old 02-25-10, 01:35 PM
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The official opinion by those that study and test how wood works is to not glue underlayment to the subfloor. It's especially a no-no to use thick glues like those that come in a tube. The thickness of the ridges creates voids where there is no glue causing vertical movement.

Furthermore, underlayments should never be fastened to the joists, just the subfloor. The idea is to isolate the tile work from the constant movement of the framing and thereby transferring this stress to the finished floor.

Versabond is a decent modified thin set, but it's an "entry-level" quality. It's widely used and will probably work well for you, but nothing to brag about. Also. large tile such as yours should be set with a "medium-bed" mortar. They are blended to minimize sagging/drooping on floor while they set up. It sounds like you're not sure on the brand though.

You may want to have a 1/2" trowel handy with those large tiles. Set a few then remove to check for at least 85% transfer, back buttering will help. And, hope that floor is very flat.

Jaz
 
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Old 02-25-10, 02:01 PM
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Thanks Jaz. I appreciate your insight. I am bummed that we get different advice everywhere we go! Hopefully it isn't going to be a problem because I don't know if we can bear to start over.

I will be sure to get the 1/2" trowel and make sure we have a really even floor. Thanks again.
 
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Old 02-25-10, 02:38 PM
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I hear ya about conflicting advise. There are many people setting tiles that should be doing something else. It is particularly bad now with the bad economy. I find roofers, drywall guys, handymen that claim to be experts in installing tiles. They may have done it many times, but that doesn't mean they're doing thing right. Many of these people are operating illegally with no license.

The few things you mentioned shouldn't be fatal errors.

Then we have the big box stores giving advice and doing saturday morning how-tos. Boy some of those are real bad. And I won't bring up the shows on HGTV.

For your next major tile job, you should consider adding as thick a plywood as possible, but use a product called Ditra (1/8" installed) to minimize build up. Plus it has many other benefits over cement backers.

Jaz
 
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Old 02-25-10, 04:09 PM
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Thanks again Jaz. I will definately be back. I was trying to stay away from the two big chains HD and L for advice on installation.... everytime I go they are full of advice but when I ask if they have ever installed it's always a no Pretty funny. I was hoping to have got better advice from an installer group from a store that sells and installs tile only. I took a class from them. Thought perhaps I was getting better advice from "specialists" rather than plumbers trying to be tile installers. Go figure. Anyway, I'll be back! Thanks a million.
 
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