Cement board install [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-14-2017, 05:44 AM
Hey folks a few quick questions..I currently am demoing the bathroom..I came across a few things as I'm demoing..
1. Can I tile over the existing glue that you can see in my pictures or do I shave it off.
2. Do I retape over the drywall seams with drywall tape or can I just put durcok alkali tape on the seams and mud it.. Thanks

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01-14-2017, 07:34 AM
If that is the paper i would pull that drywall out of there a little bit of paper is ok you can just mud then paint followed by tile. looks like the corner needs taping.

i have a bathroom to do as well just doing the floors but if i had to redo the tub surround the tile and drywall both come out as one i think thats a little too scarred up for mudding over you could mud over it in a bind lots more work

01-14-2017, 11:48 AM
Tear it out and start fresh, you'll thank us later.

01-21-2017, 11:23 PM
Hey guys! Quick question. Im going to try my best to explain this. Assuming you are installing a running bond pattern in a tub surround...I'm aware that you tile the back wall first...you find the center of the back wall, tile your way out to the corner and leave your cuts in the corners. Now my question is for the other two walls in the tub surround. Assuming that I am going to end the tub surround in a bull nose where do you start tiling at?
1. Would I start from where the bull nose Would be laid and work my way in the corner and leave my cut in the corner?
2.Finally, if it is a running bond I will need to cut a half tile every other row near the bull nose what do you guys do about these cuts? How do you try to hide them?
I hope I explained this well enough. Thanks.

Houston Remodeler
01-21-2017, 11:26 PM

Its your lucky day !

We have a whole thread (http://www.johnbridge.com/vbulletin/showthread.php?t=85869) about this very topic and a few more questions you'll have.

How cool is that ?? :postitbg:

01-21-2017, 11:37 PM
Thanks I'll read that

01-22-2017, 01:56 PM
Did that answer your questions? If not throw up a few pics of what you're working with and the tile you're using and we can figure something out.

Tiger Mountain Tile Inc
01-22-2017, 09:27 PM
I'm not sure what you mean by "leave the cut". I usually try to make the corners look like the "continue" onto the side walls. I don't know if that's helpful or not.

01-23-2017, 09:42 PM
I think he's talking about wrapping the cut off piece around the corner onto the end wall. I usually do some measuring because every job seems to be a little different. After tiling the back wall, sometimes you can still start with full and half tiles at the bullnose (end wall) and to the eye the cut tiles in the corner will look like the left overs from the back wall but are off some. The cuts in the corners can be 1/2-3/4 inch bigger or smaller than the cutoffs and to the eye still look like the pattern flows thru the corner.

01-24-2017, 09:51 AM
thanks for the responses guys...my question isnt so much about wrapping the corner..i understand that concept. Im trying to hide my cut pieces on the side walls with a running bond pattern. I understand that i leave my cuts in the corners to hide...but with a running bond im still left with visible cuts on the side walls near the edge of the wall furthest away from the corner.. so if you look at either of the side walls Im left with a full tile meeting up to a bull nose piece..then the row above it is a cut piece meeting up to bull nose...then above that is a full piece.. the full pieces have factory cuts...the half piece does not have a factory cut...how do you guys hide that cut of the half piece...hope i was able to clarify this more...

01-24-2017, 10:25 AM
Adam, I think it might have been addressed in Houston Remodeler's earlier link...but to reiterate, where a cut tile meets the bullnose, take a dressing stone and "ease" the cut. Some tiles do better than others at this. Reverse the tile, putting the factory edge up to the bullnose. Dressing the tile edge and the grout generally lets it blend into the field better than having it apparent next to the bullnose.

01-24-2017, 10:32 AM
yup! that answered my question..i didnt see it in Houstons link, but I could have missed it...it was a very good article though!

01-26-2017, 08:56 PM
Hey folks just a few questions.
1. if I were to install cement board in a tub surround for tile installation, and I plan on ending the height of the cement board just above the shower faucet is it okay to have drywall above the cement board leading up to the ceiling? I plan on tiling just above the shower faucet where the cement board ends

2. Before installing cement board is it required to place 2x4 blocks between the studs horizontally just above the tub flange around the perimeter of the tub? Thanks

01-26-2017, 09:07 PM
You want the cbu to go at least to the height of the showerhead, all the way around the shower. It doesn't hurt to put blocking in, but the combination of using the specified mesh tape and then the tile on top is usually enough. There should be a moisture barrier behind the cbu unless you are going to put a topical waterproofing (either sheet or paint-on) on the inside of the surround.

01-26-2017, 09:16 PM
So drywall in a tub surround above the cement board is acceptable?

01-26-2017, 09:39 PM

Sent from my VS987 using Tapatalk

01-26-2017, 09:43 PM
Welcome back, Adam. :)

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 to suggest one.

01-26-2017, 10:06 PM
Thanks CX

01-27-2017, 02:29 AM
So I been snooping around the site to collect knowledge and I came across control joints??? I want to know more about this. I understand you want to leave gaps around the perimeter of the room and caulk in corners and against dissimilar surfaces, but I saw people talk about not grouting a small section in the middle of the floor and apply color matching caulk instead? Could you guys help explain to me where inwould do this? Thanks

01-27-2017, 07:43 AM
typically this is done on larger installs, or rooms that are exposed to a lot of sunlight cause swings in temp throughout the day, or exterior installs. Soft joints are also used over slabs where there are control joints cut into the slab, or where there are cracks in a slab that have been treated with some sort of crack iso.

01-27-2017, 09:42 AM
The ceramic tile industry calls for movement accommodation joints in the tile surface every 20 to 25 feet in each direction for interior installations and 8 to 12 feet in exterior installations in addition to the required perimeter joints and joints at changes of plane in the backing material.

Installers frequently disregard these recommendations because nobody wants to see these soft joints in their tile installation. Some of them are lucky and get by without problems in the long term; some pay the full price.

01-27-2017, 06:40 PM
Note that in addition to a caulk like material used for movement accommodation joints, at least a few companies make engineered ones that perform the same function. The first one, and the one with the largest selection that I've found is from www.schluter.com. Depending on the grout you select, they may not be visible without looking very closely.

Note, if your baseboard covers the perimeter of your tile install, you do not need to fill that gap with caulk...just leave it open as it will be hidden from view. In that case, an air gap is much less expensive and works equally as well!

02-02-2017, 08:43 AM
I just got my order in from the tile shop. Along with my tile I ordered two schluter preformed niches...I plan on hanging durock cement board and waterproofing with aqua defense..my question is schluter niche requires unmodified thinset.. Should I use schluter niche or buy noble preformed niche.. The reason I ask is schluter requires unmodified thinset and noble requires modified..I find it pointless to open a small bad of unmodified just to embed niche. What are your thoughts

02-02-2017, 08:51 AM
I would use the modified mortar in the Schluter niches. You won't get a warranty from Schluter, but you don't need one, either. If there is any problem with the niche installation it will be an installer error, anyway. Buying the Noble niche might be a better option for you if you're concerned, though.

My opinion; worth price charged.

02-08-2017, 09:40 PM
Thanks for all The help thus far folks...im still prepping for my tile installation...i ran my numbers on the deflecto calculator and I am good for a ceramic installation on my floor.. After running the numbers though it doesn't say anywhere on how think the subfloor should be though? Currently I have 3/4 inch plywood...im installing ditra over my subfloor...is this thickness sufficient? Or should I throw on another 1/2 inch before the ditra. Thanks

02-08-2017, 09:58 PM
Adam, our Deflectometer has never heard of a subfloor. It knows only dimension wood joists.

The subfloor requirement is determined by the manufacturer of the tiling substrate or the tile industry standards. If you're using Ditra, you really want to visit their website (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0ahUKEwilzNHLj4LSAhVD3GMKHYzsA8cQFgg5MAI&url=https%3A%2F%2Fs3.amazonaws.com%2Fscclegacy%2Fmedia%2Fditra-handbook_eng.pdf%3Fv%3D201507140600&usg=AFQjCNEvUXrOUyHVbzLegxBV0uFs-MT3dg&cad=rja)and become familiar with the product. They will tell you exactly what is required for any given situation.

Without knowing your joist spacing, I can't tell you what might be required in your application.

My opinion; worth price charged.

02-08-2017, 11:18 PM
Ok I checked their website I'm fine with a single layer of 3/4 inch plywood on 16 inch joist. Thanks

02-09-2017, 06:47 AM
Is it tounge and groove?

02-09-2017, 10:05 PM
Yes sir it is.

02-09-2017, 10:09 PM
If you have room for a layer of 1/2" go for it, if not 3/4" installed properly with ditra is fine.

03-20-2017, 07:40 AM
Hello, quick question. I just started installing the cement board.. on the back wall the cement board edge where it meets an inside corner is damaged...i can't get a screw in the stub because of the damage to corner part of the board...my question is will the board still be okay when i mud and tape the corners along with my topical water proofing? I attached pictures of the damage. Let me know if the board needs replaced or not

03-20-2017, 08:54 AM
You should be able to thinset and tape that in no problem. What kind of screws are those?

03-20-2017, 09:11 AM
Durock cement board screw

03-20-2017, 09:28 AM
Good deal. It was hard to tell from the picture. Just wanted to make sure. :)

03-20-2017, 09:41 AM
Good looking out though

03-25-2017, 05:08 AM
Hello another question. How do I address the outside corner where the two cement boards touch...do I mud and tape them like the other joints? Attached is a picture

Houston Remodeler
03-25-2017, 05:16 AM

03-28-2017, 11:34 AM
I just waterproofed my bathroom with Mapei Aqua Defense. I also used the reinforcing fabric...I saw alot of people recommend just using the reinforcing fabric on the inside and outside corners...I used the fabric on the inside/outside/horizontal seams.. is the still acceptable? thanks.

01-29-2018, 09:55 AM
Hey folks I have a question. About 6 months ago I finished a shower surround at my house. It turned out quite nice, and Im more than happy with it thanks from the help from this site. The only issue I am seeing happen is the caulk from the tub to the bottom of the tile has cracked. I did use silicone color matching caulk. After realizing this I recaulked over the existing caulk and learned that doesn't work. So now I am going remove the existing caulk and try again. I guess my question is # 1. why did it crack the first time? the caulk running vertically in the corners didn't crack. I thought well maybe to much tub movement caused it to crack. #2. I read a post on a website stating that the next time I caulk the tub I should fill the tub up with water or weigh it down. What are your thoughts on that? I then started to overthink this and thought well maybe their is to big of a gap between the tub and tile. The gap in most places are 1/4 of an inch between the tub and tile. I did see one spot where the gap is maybe just over 1/4 of an inch, but I dont think its cracking just because of that. I'm just looking for a professionals thought on why this could be happening. Thanks.

01-29-2018, 10:02 AM
Quite possible that the weight of the water and bather "pulled" and stressed it enough to fail. You're on the right track with weighting it down. In a tub job, I always 3/4 fill the tub before caulking...let it cure for a day or two before draining. Seems to work well. :biker:

01-29-2018, 11:37 AM
Usually colored silicones are latex based. Maybe make sure it's a 100% real aquarium silicone.Just a thought.

01-29-2018, 11:56 AM
This happened to me as well. The Color Rite silicone cracked between the top of the caulk and the bottom edge of the first row of tile. As you mentioned, I had to mechanically remove all of it before redoing it.

I didn't fill the tub the second time as I had to be inside of it while working on it. See my question below and the responses I got.....

Starts at post #403...


02-02-2018, 11:20 AM
Hey guys thanks for replies. What brand or website do you use to get color matching silicone caulk

02-02-2018, 11:31 AM
These are our "go to" guys for silicone caulk. Any color you want.


02-02-2018, 11:46 AM
Color sil or poly sil? Should it be a sanded silicone caulk?

02-02-2018, 12:14 PM
Color Sil Sanded......for showers and wet areas...