Thinset question

grumpyhessian · 03-15-2009, 09:14 PM

Does anyone know if thinset mortar will adhere to latex based floor leveling compound? The compound I used is made by DAP. Should I scuff/sand it before applying the thinset?

JazMan · 03-15-2009, 09:43 PM

Never heard of latex based, do you mean Portland base that you mixed with a latex additive? Maybe this one? http://dap.com/product_details.aspx?...00&SubcatID=18

Any Portland based product is fine to tile over. The latex in the mix is so it'll bond better and will give the product some flex too. Technically, a steel troweled, then lightly brushed finish is best, but it'll work even if troweled smooth. What type/brand of thin set, what type of tiles?

Jaz

grumpyhessian · 03-16-2009, 12:03 AM

Hey Jaz,

The leveler is this one http://www.dap.com/product_details.a...05&SubcatID=14

The thinset, hmmmm, I can't remember the brand, but I know it's polymer fortified. The tile is going to be ceramic; probably small 1 inch hexagonal. I only used the leveler underneath a solid surface shower pan (cultured Onyx) since the floor had some low spots and the pan has no flex to it. For the rest of the bathroom floor, I figure the thinset will handle any low/high spots (up to 3/8", right?). Anyway, there's about a 2 inch strip of the floor in front of the threshold of the pan that's covered by the leveler, then it transitions to bare Durock. I just want to make sure the thinset will adhere to that one little strip. I know it'll bond the the Durock, no problem. The whole floor is Durock layed on thinset, which I spread on two layers of 1/2" exterior grade plywood, glued and screwed. I had to make up thickness after breaking up what was left of the original slab.

Bob Mariani · 03-16-2009, 07:15 AM

It will bond fine. If you want more bonding to feel safe brush on some bonding agent from the concrete section of any building supply store.

grumpyhessian · 03-16-2009, 12:50 PM

Thanks, Bob. I figured it would be ok, but I just wanted to make sure.

I'm going to be putting up Durock on the shower stall walls soon, in order to hang "subway" tile. Does this tile come in sheets, or is it a "one by one" type of thing? I'm new to the whole tiling thing. I know how to do it in theory, but practice is a whole other matter. Any suggestions?

Bob Mariani · 03-16-2009, 01:36 PM

Seal the seams of the durock with mesh tape and thinset. Then coat the entire surface with Redgard waterproofing. Durock by itself is not waterproof and neither is the grout. Smaller subway tiles come in sheets, but the size you will be using for the shower walls most likely will be individual pieces. Be sure your walls are square so the tiles will look good. Dry fit the layout to avoid making too small a tile cut at the edges and to make cuts on the back wall the same size. Do the back wall first, then the side walls. Remember to order the bull nose tiles for the front edges and the curb. Use modified thinset and not mastic for wet conditions. Be sure to seal the grout after letting it dry for three days.

grumpyhessian · 03-16-2009, 07:59 PM

HI Bob,

OK, thanks. I'm thinking that Redgard isn't sold at Lowe's or HD. Should I buy it online? Spray it or roll it?

Bob Mariani · 03-16-2009, 09:40 PM

Quote:

Originally Posted by grumpyhessian

HI Bob,

OK, thanks. I'm thinking that Redgard isn't sold at Lowe's or HD. Should I buy it online? Spray it or roll it?

Lowes should have it in the tile department. As well as any tile store or Home Depot. It is brushed on.

grumpyhessian · 03-24-2009, 09:13 AM

OK, I found the RedGard. When sealing the seams of the cement board with thinset and tape, does this include the corners, as well? Also, should I use the Redgard on the cement board on the floor?

Bob Mariani · 03-24-2009, 09:32 AM

yes corners too. And yes Redgard on the floor.