28 Days to lay tile???

tomptat · 08-23-2009, 07:48 PM

Hi there, thx to all who helped me on my last post, worked out well. Now I'm attempting a shower pan. Sandmix, PVC membrane, more sandmix. everything going well so far, and the guy at Menards says wait 28 days to tile. I KNOW that the theory says it takes concrete/cement 28 days to cure, but I have my doubts that most tile guys wait that long to get their money on a shower job. Any thoughts. I searched the flooring forum and didn't find anything. THX.

Tom

**Termite** · 08-23-2009, 09:06 PM

Don't worry about 28 days. You can tile in a couple of days. The 28 days is when concrete reaches its design compressive strength, and that'll happen under the tile just fine.

Sand mix? You don't mean sand mix concrete (like QuickCrete) do you? Shower pans are not poured like regular concrete. Properly done you'll use a shower pan base mix that is very very very very dry, like moist sand. The base material is literally packed in place and screeded off with a trowel. Water can be sprinkled lightly on it to ease troweling. Normally poured concrete just isn't as strong. The pros at a local tile store can walk you through the process. Hopefully Menards didn't steer you wrong and sell you regular sand mix concrete.

JazMan · 08-24-2009, 02:26 PM

Tom,

One reason those types of stores are able to usually sell a little cheaper is because they refuse to hire knowledgeable people in the departments that require it.

This is especially true in the tile aisles. So much wrong info dispensed there. Shop there at your own risk is what the sign should say.

You do not wait 28 days for the deck mud to fully cure, just like you do not have to wait 28 days to park on your new driveway. In the old days, the recommendation was to set the tiles in the "still plastic mud" or wait 3 days for it to cure. It depended on the size of the area to choose which.

You can install your tiles the next day, overnight drying is enough. Or, when building an entire shower, you can cover the deck mud with cardboard and set the tiles near the end of the project.

The proper mix to use is "Sand Mix", some call it "Sand Topping Mix" http://www.quikrete.com/ProductLines/SandToppingMix.asp It comes blended in the bag at a 3:1 ratio, ideally a 4:1 or 5:1 is used for floors. The 3:1 is great, but a bit harder to work with, so you can blend some more sand to it if you like. The ratios are shown by volume not weight.

Jaz

Quickdraw · 08-26-2009, 05:05 PM

Im doing the same thing - building a shower pan. Mine is on a concrete basement floor. Should I put down a vapor barrier before the pre-slope? It seems like I should but the John Bridge book says to sprinkle thinset on the concrete floor to bond the preslope to the floor itself.

JazMan · 08-27-2009, 12:40 AM

Hi Quick,

All depends on what you're trying to do. On a large floor you may want to place a "slip-sheet" to isolate the new deck mud from the old cracked un level slab. On smaller areas like a shower you may want to bond the new mud to the old slab.....hence the thinset mortar or Portland slurry.

I guess you're not convinced on a Kerdi Membrane-Drain system? You're going with the old method huh? I (and John Bridge) highly recommend you reconsider.

See how to do the mud floor in a Kerdi membrane-drain over a slab here; http://picasaweb.google.com/tile4youinc Also click on and study the "old method" you're considering.

Quickdraw · 08-27-2009, 10:04 AM

Quote:

Originally Posted by JazMan

Hi Quick,

All depends on what you're trying to do. On a large floor you may want to place a "slip-sheet" to isolate the new deck mud from the old cracked un level slab. On smaller areas like a shower you may want to bond the new mud to the old slab.....hence the thinset mortar or Portland slurry.

I guess you're not convinced on a Kerdi Membrane-Drain system? You're going with the old method huh? I (and John Bridge) highly recommend you reconsider.

See how to do the mud floor in a Kerdi membrane-drain over a slab here; http://picasaweb.google.com/tile4youinc Also click on and study the "old method" you're considering.

The $125 cost of the Kerdi drain was a turn off... The concrete shower floor itself is 3'x4' with a seat at the end another foot or so. I painted the seat with Laticrete membraine paint (3 coats) and will cover the seat with DensGurad and do not plan to put a membrane on the seat. Ill think about the Kerdi some more....

Quickdraw · 08-28-2009, 12:43 PM

JazMan,

OK, you win, I ordered the Kerdi drain... this way I only have to do one slope, not two.

The drain kit comes with four inside corners and 2 outside corners? Will the outside corner piece fit over the curb with a return wall?

Wouldn't type S mortor be better than the sand topping for the pan?