Different advice on Mapei thinset mortars [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-18-2012, 12:48 PM
Hi. I'm redoing my shower/tub and bathroom floor. My shower walls are bare to the studs and I'm going to put 1/2" Durock and thinset the seams before waterproofing with Aquadefense on top of backerboard. I'm using subway tile with an accent band of glass tile mats and constructing a couple niches in the shower/tub area. I'm planning to use Mapei products since my local big box store carries these products. I've received conflicting information as to which type of Mapei thinset to use.

Two different big boxes gave me different advice for the wall mortar. One store said the Ultraflex 2 needs to be used for wall tile; otherwise I'll have to hold the tile onto the wall for a while (not as sticky as Ultraflex 1). They said the Ultraflex1 was fine for the backerboard joints and floors. They also had the Ultralite mortar too. Another large box said that Ultraflex 1 was fine for the backerboard joints and for placing wall tile.

I've done floor tile a few times but have never done wall tile. I've not used any Mapei products previously (only Versabond). I'm just looking for some advise for an amateur (I wouldn't want to use any rapid set). I don't have problem spending some extra cash if it's the right product. I'm just surprised at the differences in the explanations between the products (the prices show there is a difference). Menards had the Ultraflex 1 and 2, Ultralite, and Ultraflex RS. Lowe's didn't carry as many Mapei thinset products (not that this is bad, but I thought it was interesting and confusing that the product line varies between stores).

If someone is familiar with Mapei products, please let me know what type of thinset you use for shower wall tile (Ultrafllex 1 or 2?). Also, what thinset do you use for floor tile? I was planning to use Ultraflex 1 for backerboard joints (with fiber tape) on the wall and floor. Ultraflex 1 would also be used between the subfloor and backerboard. Thanks for any feedback!

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02-18-2012, 01:47 PM
Andy, neither Ultraflex I or II are non-sag thinset mortars, so you will have to support the tiles until the thinset sets. Spacers are normally use for this, but you can use any combination of tape, spacers, pins or brads to do the job. With a surface waterproofing membrane, you obviously do not want to use pins or brads.

If not for the glass mosaics on a membrane, I'd say that Ultraflex I would do for all applications you are planning. Glass needs a bit more latex, so if money is an issue, use Ultraflex 1 for taping and mudding, and for setting most of the porcelain tiles, then switch to Ultraflex III (Ultraflex II is not recommended for glass tiles) or Mapei's Kerabond with their Keralastic admix for the glass mosaics.

John Bridge
02-18-2012, 01:50 PM
Welcome aboard, Andy. :)

One must be careful when listening to the expert in the aisle at the big box. ;)

02-19-2012, 11:53 PM
Thanks for the replies. It's good to know about the additional latex for the glass tile. I was planning on using spacers while I tile. Is there a good non-sag thinset, or is non-sag basically the same as rapid-set type? If using Versabond (or another type) would be a better choice, let me know. Thanks.

02-20-2012, 02:05 AM
Laticrete 4xlt is a superb non-sag thinset. Doubt you'll find it at a big box store tho. Check around your local tile stores. This is multi-purpose thinset that can be used for thin-bed or medium-bed/non-sag applications so make sure to read the directions so that it is mixed properly.

02-26-2012, 02:31 PM
I want to build a shower niche that will be approximately 42" high by 12" wide. The shower tile will mainly be subway (3"x6") tile with a glass accent strip. The niche will use bullnose subway tile on the sides with 12x12 mosaic tile in back. I would like to use 1/2" marble for the base and 3 shelves. I am planning to slide the 1/2" shelves on top of the tile ends which line the sidewalls of the niche. Is there any reason why the shelves should also extend over the back tile? Ideally it would be nice to not mortar the shelves to the back to avoid drainage problems (no need to slope), and so the back mosaic tile may be continuous top to bottom (no cutting). The bottom of the niche will have the base slab slightly sloped for drainage.

Also, should the bottom shelf be caulked at the joints instead of grouting? If caulking, then I'm assuming this would apply to any shelf joints too? Thanks!

02-26-2012, 03:18 PM
I would recommend using 3/4 inch marble (counter top material) and check for veins or weaknesses perpendicular to the long dimension. http://www.johnbridge.com/vbulletin/attachment.php?attachmentid=116481&stc=1&d=1330291064

02-26-2012, 03:54 PM
I was going to do my the same way as you are suggesting. I don't see an issue with it, except that maybe stuff would fall at the back of the shelf, or get caught in there. Also would be hard to clean behind the shelf. So I decided not to leave a gap.

The tile on the back of the niche carries through, the shelf is in front and held up on the sides. It buts almost tight to the back of the niche though, and I will fill that with Kera-poxy when I do the shower grout.
Regular grout is ok, I just like Kera-poxy in my showers.

02-26-2012, 04:58 PM
Thanks for the replies and pictures Petr and John. I was getting a little hung-up on planning grout lines and the niche framing, but your pictures put this into perspective. Looking at pictures of similar projects really helps for getting ideas.

I'll use the thicker counter top marble. I should be able to find some good remnant marble. The marble samples I bought were actually only 3/8" thick. Can a regular tile wet saw cut 3/4" marble?

I think I'll leave a small gap in back of the shelves for water flow, and for the continuous look of the mosaic tiles. Although, I am a little concerned with cleaning etc.

Did you guys do anything special to finish the outside corners? Petr/John, both your outside corners look good so I'm just wondering if you put some type of finish strip, bullnose, or just left an infinished tile edge? I want to keep the look clean without any heavy border. If it's common to expose the edge of the side tile instead of a bullnose finish, I'll go this route.

02-26-2012, 05:55 PM
I was getting a little hung-up on planning grout lines and the niche framing, but your pictures put this into perspective.

If you're using a preformed niche box, you'll be stuck with its dimensions and will have to try to place it as symmetrically as possible in your layout. If you're building it yourself.. simply make it the right size that it fits perfectly into your layout.

02-26-2012, 07:13 PM
here is one with what I call a "soap bridge" made of quarzite. If you have time for it you can tile up to one row short of the niche height and then build it in and waterproof. Otherwise your chances of being 1/8" off are pretty good


02-26-2012, 07:18 PM
Welcome, Andy. :)

It'll help if you'll keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. We can give it a more generic title any time you'd like.

02-26-2012, 09:50 PM
The corners on mine used a Schluter Jolly trim.
I've done it before with exposed edges of the tile. How that would look depends on the tile your using. Does the color carry through? When i do it this way I let the face tile lap over the tile of the sides of the niche tiles. Does that make sense? I don't have a pic of that.

05-10-2012, 12:19 PM
After a little delay I'm getting ready to receive some decorative tile so I can finish this shower tile project. The information and pictures have all been really helpful. I just have a few other questions:

1) Inside corners: Does it matter if the tile overlaps the tile on the perpendicular wall when placing tile, or should you leave a gap and fill with grout. I was going to overlap the opposite wall tile but still leave a 1/16" spacing for grout, or isn't this recommended. My tile is mainly 3"x6" subway tile.

2) Niche corners and shelves: Does the same corner tiling apply to niche corners (ie overlap ok)? I was going to put the niche's bottom shelf back to the CBU and then have the back wall tile (and side wall tile) overlap overlap the bottom.

The middle shelves of the niches were going to sit on top of side wall tiles. Can these middle shelves simply sit on top of the side tiles, and then caulk the underside of shelf when finished? If I don't do this, I'll need to put a spacer between tile and shelf and hopefully get the thinset to hold the shelf until grouting.

3) Caulk or grout inside corners? ....main shower area and niches.

4) Cutting glass tile. I will be using some 2"x1" glass tile sheets 1/4" thick for decorative treatments. I've read people using a wet saw, scoring tool, or some other glass cutter for this type of cut. I have a wet saw and an ok blade that is rated for cutting my marble shelves. Any recommendations for cutting the glass tile? I don't mind buying a tool if it's reasonably priced.


05-10-2012, 05:01 PM
Thanks Bob. That makes sense.

2) Any idea for setting a shelf (making it stick) within a niche. My plan is to set the shelf over the side tiles only and leave a gap in back (the gap won't be easy to clean but the back of the niche will have a continuous decorative tile that I don't want to cut). I think what I'll do is try and get some thinset on the ends of the marble shelf and put a spacer between the supporting tile and shelf. I'll then be able to grout the tile/shelf joint on the underside of the shelf. A previous post by PetrH has a picture and it appears that's what he did.

3) Ok

4) I'll check out a glass blade for the wet saw. Any advice for finishing the cut edge? I'll have a 6" glass mat (2"x1" tiles) ending at outside corners. I'd like to round the edges if it's possible.


05-14-2012, 11:34 AM
...just a little background with what I did for my niche shelves before I ask about hardware in the niche. I started working with some of my niche marble shelving to see how easy it was to cut and finish. I was surprised how well sand paper can finish cut edges and polish marble. I decided that the 3/8" thick marble tile might work for the shelves (I was able to purchase at a local store and at a good price). Some previous posts suggested thicker marble around 3/4". Yeah, they were right. I tested the 3/8" pieces to see if they could withstand a shampoo bottle dropping from a 2" height. The test piece broke right away. My niches are 12" wide and 6" wide. I just read about using a marble threashold which is 3/4" thick and many big box stores carry on the floor. The plan is to use the thicker 3/4" marble. I don't want to ever have to deal with replacing a shelf.

I'm brainstorming to figure some type of hardware to install that would let us hang scrubby sponges in the shower niche. The best idea I have is to install a bar across the niche which would allow hooks to be hung for the sponges. I figure the hooks could be replaced and changed as needed (or just removed and used as a small towel bar).

Has anyone installed a bar across a niche before? I'm guessing you could just build it within the side tiles? Stainless steel (rust??) or other material? I'm not sure what would work the best. A bar seems like the most flexible approach, or does someone have another idea?

05-14-2012, 11:43 AM
Welcome, Andy. :)

Seems a fella'd need a pretty big niche to use a bar within it to hang things, but I see no reason it couldn't work. No, I've never done one.

I would think stainless steel or brass if you're not trying to match the finish of the rest of your shower fixtures.

And just notching or drilling the side tiles should be sufficient for the mounting.

My opinion; worth price charged.

05-14-2012, 04:43 PM
The bar would mainly serve as a fixture to hang some other hardware (wire or plastic hooks, etc) so that you could then hang a sponge or something to the hook. The hooks could then be simply tossed out after they become corroded or stained. The niche I would like to put this in is only 6" wide.

It seems like a lot of the stainless steel shower caddies end up rusting sooner than later (maybe these cheap things are chrome plated...not sure). I'm just trying to figure out a good way to incorporate a couple of small hooks into the niche. I've seen pictures of larger hooks in showers where people mounted them on the wall but I'm not crazy about fastening through the water membrane, or having a metal mounting bracket in a wet area. Another option would be to find ceramic hook fixtures that get thinset on the walls, but I haven't seen anything like this.

Are there different grades of stainless steel? I'd install a stainless bar, but I'd want to make sure it would stay remain "stainless" and not start corroding after a few years. Thanks.

Dave Taylor
05-14-2012, 06:27 PM
Are there different grades of stainless steel?

Yes.... many.

Being a boater on the Chesapeake has taught me that 'salt water takes no prisoners' and yes..... stainless will rust.

But in a shower "314" or "316" stainless should be fine.

See HERE (http://www.corrosionist.com/Stainless_Steel_grades.htm).