Premix versus me-mix thin set

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Old 12-18-07, 01:56 PM
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Premix versus me-mix thin set

I am preparing to tile a laundry room floor and a bathroom floor. I am relatively new to tiling and I was wondering what are the opinions of premix thinset versus mixing the thinset myself?

Since I'm new to this, I expect to work slowly at first. I imagine that means that I should not mix too much thin set at once. I thought maybe it would make more sense for me to use the premix, since it will allow me to work a slower pace without have to mix frequent, small batches of thinset. But I'm not sure if the premix is a poorer quality. Since I'll be tiling over Ditra, I believe that means that I need to use unmodified thinset.

Here are some other threads that I've started about this project:

http://forum.doityourself.com/showthread.php?t=327633
http://forum.doityourself.com/showthread.php?t=327892
http://forum.doityourself.com/showthread.php?t=327490
http://forum.doityourself.com/showthread.php?t=327269
http://forum.doityourself.com/showthread.php?t=320190
 
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Old 12-19-07, 07:05 AM
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Just to clarify things, THERE IS NO SUCH THING AS PREMIXED THINSET!!! I wish companies would stop marketing that garbage as such since all it does is serve to trick the diyer who is looking to do a job right into using bad products.

Use unmodified thinset, from a bag. You will need to mix smaller batches, just read the mixing instructions on the back and start off with a reduced amount of water and an approximation of the thinset you need, for example, 2 qts water to 1/3 of a bag. Add the water first, then the thinset powder. You can mix an amount that size pretty quickly with a margin trowel. In the tile tool sections of your big box stores, the margin trowels are pretty stubby. Walk over to the concrete tools and get yourself a longer one. A 5 or 6" margin trowel will work nicely for you. Mix, let it sit for about 10 minutes and mix again. It should hold your trowel lines with no slumping and no breaking up. Add small amounts of powder or small amounts of liquid to get it right. A word of caution, small amounts of water go a very long way. 1/2 oz or so at a time of it's too stiff.

You will find the margin trowel turns out to be your most useful tool actually. Use it to keep remixing your mortar every 20 minutes or so. A quick spin in the bucket extends your pot life. Use it to scrape excess mortar from your trowel to keep the notches clear, use it to scrape thinset purge, use it to scoop mortar out of the bucket onto the floor. It's the perfect tool to pop under your tiles to pull them up when you need to either readjust the thinset underneath or when you just do a thinset coverage spot check. When you finish tiling, it's the perfect tool to scrape around the inside of the bucket to remove as much thinset as you can before cleaning the bucket out with water.

Whatever you do, do not use Customblend from HD. For unmodifieds, either go to a tile store or Lowes sells Laticrete 317 or megabond. Either will work fine. Hydroment makes "Ditraset" you could go to their dealer finder:

http://www.distriblocat.bostikfindle...rtars&zipcode=

and maybe get the name of someone near you that stocks the Ditraset.
 
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Old 12-19-07, 08:13 AM
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Thanks for the reply.

I will stay away from Customblend. Just curious about why it is to bad.
 
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Old 12-19-07, 08:50 AM
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Being so low end, your getting a lot of fine sand and just a little portland, and not even the highest quality of portland. The portland gives the bond, the sand gives the bulk. Especially with such a thin layer of thinset as you have under the Ditra, there's really not enough quality in the product to give it a good bond strength. The $10 or so and up range bags of unmodified give you a richer, higher quality, stickier product.

Use gray to lay the Ditra. You'll see the gray color through the orange as you lay it out into your thinset and press it into place. You'll know you have good coverage under it then. Comb straight lines,no fancy swirls or you'll just trap air under the Ditra.

Gray or white thinset over it depends upon tile selection and grout selection.
 
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Old 12-19-07, 01:07 PM
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Originally Posted by Tilebri View Post
...For unmodifieds, either go to a tile store or Lowes sells Laticrete 317 or megabond. Either will work fine. Hydroment makes "Ditraset" you could go to their dealer finder:

http://www.distriblocat.bostikfindle...rtars&zipcode=

and maybe get the name of someone near you that stocks the Ditraset.
I'm having trouble finding Hydroment DitraSet (or Durabond D25 DitraSet).

What about Durabond D50 or D5 thin set mortars?
 
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Old 12-19-07, 02:45 PM
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Gaetano,

You need UNmodified thinset mortar for under and over Ditra when tiling over a slab. Somewhere on the bag it'll refer to this spec; Exceeds ANSI A118.1 with water. When it says that, you'll know it's unmodified.

DuraBond D5 says this: # Exceeds ANSI A118.1 with water
# Exceeds A118.4 and A118.11 with D-L16 or D-L36 Therefore this is a good choice. Just mix with water.

DuraBond D50 says this:
Latex-Modified Add water only

Exceeds ANSI A118.4 and ANSI A118.11
Therefore it's modified, so do not use it.

Jaz
 
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Old 12-19-07, 03:17 PM
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Originally Posted by JazMan View Post
Gaetano,

...Somewhere on the bag it'll refer to this spec; Exceeds ANSI A118.1 with water. When it says that, you'll know it's unmodified...

Jaz
JM,

Thanks for that bit of info. Very useful.
 
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