Gutted my bathroom [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-13-2010, 03:49 PM
Hello all,

I am new to this forum, and have a couple of questions. I have just finished removing the old mud-tile tile, walls and floor in one of our bathrooms, old tile was a bad green color. My subfloor is 1 x 8" boards on 2 x 10's. I am going to install 2" hexagon marble on the floor, about 3/8" thick. The old floor thickness was about 1 1/4". I need to make up the difference with plywood / CBU or Plywood and Ditra. This is a small bathroom, about 40 sq. ft. of floor, do I need the Ditra for this small of an area?, or just 1/2" ply + 1/4" CBU. I don't want to have to adjust the closet flange unless I have to, cast copper.



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Shawn Prentice
02-13-2010, 04:02 PM
Greetings Robert,

Yes 1/2" ply over the solid plank floor, then either 1/4" cbu or ditra would work. If you use cbu, then just get a high-quality modified thinset. Also, 2"x2" is the minimum tile size for ditra, so if you are no less than you're good.

The flange is what it is. If you do a proper install and it needs to be extended, then that's what you do. IOW, don't compromise your install by designing around the height of the flange.

02-13-2010, 04:40 PM
I have another question on the wall tile. I am using a 3 x 6" subway, at the tub surround, I will end with a bullnose piece, so every other course will have a cut half tile. Do I ease the cut edge so I don't have a sharp edge and place the cut edge next to the bullnose piece?


Shawn Prentice
02-13-2010, 04:43 PM
Yes, Ease the edge a bit.

02-19-2010, 06:23 PM
Many of the post I read on this site talk about waterproofing, such as RedGard, over CBU for Tub/shower installations. I am getting ready to tile a tub surround and most of the instructions I read, including FineHomebuilding magazine articles do not mention the use of a waterproofing material, just tile right over the CBU. When should a waterproofing material be used? Is this just an added measure of protection? Thanks.


02-19-2010, 06:30 PM
Hi Robert. You need a waterproof membrane. Either felt paper or poly under the CBU or a paint on membrane over the CBU but not both.

02-19-2010, 06:31 PM
A vapor barrier is required if you are going to shower in it. Water will hit the walls, you can simply use 15lb felt behind the cbu, its cheap and works great.

02-22-2010, 04:56 PM
My bathroom renovation will include a 2" hexagon marble tile. This material is in approx. 1 foot squares on mesh. What is the notched size trowel to use? And is Versabond ok for this material. Substrate will be either hardibacker or cement board. This material was expensive, for me anyway, so I don't want to screw up. Any precautions working with this marble material? Thanks


02-22-2010, 05:18 PM
Wet your board down some. No standing water, but definitely dampened.

Versabond is good.

I like the 1/4" square notch with flattened ridges. Most will use a 5/16" v notch though.

Biggest problem with mesh mounted material is sometimes the tile isn't set properly on the sheet and requires you to straighten it out. Check the sheets before you lay them. I cut out bad ones beforehand and lay them individually when I set the sheets.

Houston Remodeler
02-22-2010, 05:20 PM

Versabond is just fine. :yummy:

A vee notched trowel, about 3/16" should be good.

tips o' de trade-

The hardi will want to suck the water out of the thinset. Wipe it with a damp sponge as you go to wet it down a little and remove any dust and dirt.

If the thinset squishes up between the tiles use a smaller trowel or tilt the trowel closer to the floor.

float the floor as flat as possible before tiling. Small tiles like very flat surfaces

the hex pattern will make your eyes go crazy if you stare at it too often. :wtf: Very quickly you will be seeing wide and skinny grout joints everywhere. To reassure yourself you are not insane, stagger the sheets like bricks, don't install them like a checkerboard. The offset sheet will help you guide the last sheet grout lines.

You can play with the height of the grout lines to make the floor tiles appear to be all perfectly spaced apart. Higher joints look wider, lower joints look thinner.

If you feel the need to start laying the tiles one at a time - put the trowel down and rest for a spell. Perhaps long enough to convince the spouse to hire this one out.

02-23-2010, 07:39 PM
Thanks for the replies, I checked some of the sheets and there is some irregularity, I'll try to adjust the worst. I know it is not going to be perfect. Any preference between hardi or cementboard for floors? What do you use to press the sheets into place, block of wood, or float?


02-23-2010, 07:51 PM
Robert, I have a big ol' float that was given to me a few years bag. It is way too heavy to grout walls and ceilings, but is just right to tap mosaics into place. So a float will be fine. I prefer to use cement board (permabase) over hardie. Also, I am like Paul and use a good 3/16" v-notch trowel. Though, I have used the Kerdie trowel for some thin mosaics.

02-23-2010, 08:47 PM
You can play with the height of the grout lines to make the floor tiles appear to be all perfectly spaced apart. Higher joints look wider, lower joints look thinner.

Paul makes a great point here, and the flip side is: BE CAREFUL about the grout height in the joint, because if you're not paying attention, then they will all LOOK different even if the tiles themselves are all evenly spaced. I had this problem with my hex tiles and you can see photos of my lack of attention to this detail in the link in my signature. Hard lesson to learn.

02-24-2010, 12:04 PM
I am not sure if I will have an issue with the grout height because these tiles are flat 3/8" thick. So, I imagine grouting flush with the top surface, I will try to attach a picture.

Houston Remodeler
02-24-2010, 06:41 PM
That will make a nice looking floor. But then I AM Italian and we cover everything in Carrera marble. You should see my fridge.:wtf:

03-20-2010, 07:25 PM
In my hast to get the durock installed in my tub surround I did not leave the recommended 1/8" joint at one horizontal joint on the long wall. Is this a problem, should I reposition the top sheet to gain the 1/8" joint? Thanks.

03-20-2010, 08:06 PM
I've never encountered a problem with it like that.

03-21-2010, 07:07 PM
I am getting ready to install some similar material, a 2" hexagon marble that has a mesh similar to that pictured. Reading the instructions for Versabond and some of the other Custom Building mortars, they do not recommend for resin back stone or marble, they refer to use an epoxy mortar. What exactly is a resin back tile? How much more difficult is epoxy mortar to use?, other than the short working time.

Tool Guy - Kg
03-21-2010, 10:52 PM

I moved your post off onto it's own because it was in the midst of overlapping conversation from the other thread that was adding confusion. And you deserve your own thread to discuss. Robert is referring to this post with pictures (

If the back of your tiles look like pictured, you don't have resin backed tiles either. Resin backed tiles look like they have a coat of epoxy (there's your resin). Can you post pics of what you have to confirm, or are you good? :)

Oh, before I forget, you wanna know about epoxy thinset. It's expensive and messy.

03-25-2010, 06:17 PM
Here is the marble floor tile I am using, and the mesh backing.

03-25-2010, 07:00 PM
That is not a resin backed sheet mosaic. Versabond should do just fine :)

04-10-2010, 06:11 PM
I think that the TCA guidelines says do not use primer paint on greenboard before thinset. Is it prefered to tile directly to greenboard without primer paint, this is for non-wet walls. Thanks.

04-10-2010, 06:23 PM
Welcome, Robert. :)

This part of your bathroom renovation?

The TCNA will have no published guidelines on the use of primer on MR Board that I'm aware of.

Not sure what you're looking at there.

If it's a dry area you can tile directly to your MR Board (greenboard) if you want. But if you get a choice, I'd recommend regular sheetrock instead.

My opinion; worth price charged.

04-10-2010, 06:23 PM
I wouldn't waste my time on "greenboard." Used to be that they said it was "water resistant," but it will dissolve about as quickly as regular drywall. There is some kind of "waxy" coating on it...s'posed to make it repel water, but I wouldn't use it unless there is a waterproofing membrane involved.
What is this for? If it's a shower, drywall and Kerdi is all you need. If not Kerdi, CBU and a REAL waterproofing system.

Tell us more about your project and we can give you better advice.

04-10-2010, 08:03 PM
Thinset will stick to greenboard real well. It will allow you more time to get the thinset covered since the moisture in the thinset will soak in slower.

04-10-2010, 08:55 PM
Thanks for the replies. I am re-doing the whole bath, I have durock at the tub/shower and sink area and was only going to tile those areas. Now I decided to continue the tile on two walls that are new greenboard.

04-10-2010, 08:59 PM
Robert, it'll help if you'll keep all your project questions here on one thread so folks can see what you're working on and what's been previously asked and answered. :)

The Kid
04-10-2010, 09:46 PM
If you use the flat side of the trowel to "key-in" the thinset, then comb it out, you will be good. This will help improve your bond as the morter will be forced into all the mini cavities and crevices of the substrate.

04-10-2010, 10:53 PM
You should see my fridge. Inside or out? :D

08-01-2010, 08:09 PM
After six months we have finished our bathroom. We demolished everything down to the studs. We used Florida Tile subway, they are "hand molded" and have some irregularity, which made installation a bit more difficult. At first I was using all of the tiles right out of the box, as I progressed I found it helped to discard the most irregular shapes. The floor is 2" marble octagon on hardiboard. The endwall of the shower was a solid wall before, now with the glass it helps to open up this small space. I have attached a few photos.


08-02-2010, 05:09 AM
Nice job, Robert! I like the subtle accents you used. :clap2:

08-02-2010, 04:32 PM
Thanks for the comment, my wife made all of the selections, and we did the installation together. She did all of the grouting. Here is a photo of the floor and vanity.