I get quite a few questions here concerning cracking grout on a shower bench. In some form or another people are mostly asking whether they should caulk or grout the outside corner, where the bench top meets the vertical tile on the face. The reason for asking me this, however, is what I will address in this post.
Most people begin with something like ‘my grout has cracked and now water is getting behind my tile and my bench is starting to swell, there was an eclipse, my dog has burst into flames…it’s a whole thing. Should I grout or caulk that?’
Unfortunately this happens a lot (the bench, not the eclipse or k-9 flames…), and everyone thinks about it backwards. It is not the grout (or missing grout) that caused water to leak into your bench and swell the framing, it was the swelling of the framing that caused your grout to crack. Tile and grout are not waterproof. The reason you have this issue is because your bench was not properly waterproofed before tile was installed.
I get a LOT of questions from my readers about basic shower construction. I understand that my readers don’t consider this stuff basic and there’s no problem with that. The problem is that I end up answering the same questions over and over and over… So, to save what very little is left of my sanity (which is a number roughly equivalent to absolute zero) I will cover some basic things here so I can simply reply ‘read this’.
If you’ve been channeled to this page by one of my smart-ass comments please take no offense to it, I’m here to help. Please understand that I currently have over 12,000 comments (questions) on this site (seriously) which I’ve answered – every one of them. I’m just trying to make your life (mine) easier. I will continue to answer every question I’m asked, I’m just super cool like that. If, after reading through this, you still have questions feel free to ask them in the comments below.
You can also download my shower waterproofing manual which should answer a lot of questions and cover basic techniques and methods you may be confused about. Go ahead, it’s free. So without further ado (doesn’t even look like a word, does it?) let’s get on with it. (For all my readers who feel the need to correct me: I KNOW it’s actually ‘adieu’ – I was being facetious. Thanks. )
I am not writing this to tell you why your tile is cracking or why your grout is cracking – I have other posts that may tell you that. (Click on the pretty little links ) If you happen to have Schluter Ditra as your substrate, this post will tell you why either one of the above may be happening.
While Ditra is my preferred membrane for floor tile installation (as well as countertops and tub decks) it absolutely needs to be installed correctly. The two main techniques for this are fairly simple:
Make sure the cavities (waffles) are filled correctly
Install it over an approved substrate (and with the correct type of thinset mortar)
In my previous post I beat you to death with the reasons why you absolutely need a soft joint (control joint) in certain tile installations. Sorry about that, I have a hard time expressing how important they are without being a dick. They”re important – really. So now that I’ve properly reprimanded you it’s time to show you how to do it.
That title right there is absolutely ripe for me to go off on a sophomoric, mildly humorous rant about the viability of inferior illegal plant use. But I’m not gonna do that. (Okay, maybe later…)
A soft joint, or control joint, is simply one grout line, all the way down the length of your installation, that is filled with colored silicone or caulk rather than grout. The purpose of a soft joint is to allow movement in your installation without cracking tiles or grout. When placed properly it will absorb any ‘normal’ seasonal and structural movements inherent in structures.
There are guidelines that need to be followed for a soft joint to be effective. The TCNA guidelines call for a control joint every 20′ – 25′ in each direction for interior installations and every 8′ – 12′ in each direction for exterior installations. Interior installations which are exposed to direct sunlight also need control joints every 8′ – 12′.
I know there are some people out there (not my regular readers like you!) that read what I write and think to themselves ‘okay, but I’m sure that won’t happen with my installation’. So periodically I’m gonna post things like this that show exactly what happens when things aren’t built correctly. And yes, it will happen to yours, too, if the proper steps aren’t taken. If you care to see more train wrecks you can check out my ‘flawed‘ page wherein I post photos of absolutely horrible tile installations which I’ve torn out and replaced.
See that crack in the tile right there? (The line down the center is not a grout line – it’s a crack. You can click on it for a larger version) That bathroom floor is less than eight months old. It was installed with hardibacker over the subfloor and thinset. At least that part is correct, but that was about it. There was no thinset beneath the hardi and the seams between the sheets were not taped and thinsetted. To a lesser extent the correct screws were not used in the hardi – they committed the cardinal sin of using drywall screws in the backerboard. Yeah. Wrong.
As some of you may know (or simply don’t care about – but know anyway) I actually do reply to every question I’m asked on this site. It may take a while for me to sober up enough get enough time away from work to answer it – but I do. As such I am frequently asked the same or similar questions a lot. I’m going to start turning these questions and answers into blog posts to leave myself more beer drinking time to help people with the same problems. So here’s my first one. If you have a suggestion for future posts like these just let me know and I’ll be more than happy to cobble together some similarly ridiculous advice for your problem. I will not share any names or other information with anyone else because – well, it’s none of their damn business – so no homeowners were harmed during the writing of this post.
Here’s the question:
My husband and I have recently tiled our kitchen and laundry room. It is a 35 year old house that had kitchen carpet in both areas. We removed the carpet and old linoleum was underneath. We installed backerboard thinset extra like you suggested on this site, which i read just now to make sure. Now we have something like a fault line running through our grout. We did remove the grout down to the thinset and cleaned out as much as we could then regrouted. Of course it cracked again within 2 weeks of the repair. I do suspect a tile is moving but is there any sure way to know if it is just that tile or more and if so what is the best way to fix it. Also I am not sure why it would move with backerboard under it could it be the floor itself?
My response to this all-too-common question is a bit complicated since it is rarely one specific reason and could be a number of things.
Your grout is cracking for one reason and one reason only: your tile is moving. That’s it. Okay, that’s not it – Unless your grout is non-sanded and was installed in the last 28 days – your tile is moving. That’s it. Yes, 28 days has significance, it is the amount of time it took my teenage son to clean his room. It is also the amount of time it takes for grout to fully cure.
So let’s figure out why your grout is cracking:
Your grout is newly installed – incorrectly
If you do have grout that was installed within the last 28 days then your grout is not actually cracking – it is shrinking. Either your grout lines are too large for non-sanded grout (smaller than 1/8″) or it was incorrectly mixed. NO! You cannot simply mix up more and fill it in. Read this post about adding more grout to your grout lines.
If your grout is not fresh, well, you need to repair the reason your tile is moving. And stop using your pogo stick in the house. Diagnosing the reason your tile is moving is extremely varied. It could be anything from inadequate deflection in your flooring for the type of tile all the way up to and including the aforementioned pogo stick.
A common misconception about tile and grout is that grout will somehow assist in stabilizing a tile installation. It does not. Unless you use epoxy grout it will add no significant structural elements at all.
So why should I use grout?
Grout is, structurally speaking typing, simply there to fill the spaces between tiles. That is an oversimplification, but it describes the grout’s function. More to the point, it is there to keep other things out of that space. Without grout the possibility of dirt, grime and all sorts of unruly, unwanted things may collect in the spaces between tiles. This may lead to not only unhealthy conditions, but also the chance of damaging your tile while trying to remove those things.
Does epoxy grout help stabilize tile?
If you’ve read any of my other posts regarding grout you have more than likely seen me state that epoxy is different. This subject is no exception.
Epoxy grout will actually add to the stability of your tile installation – to an extent. Epoxy will stabilize only the area between the tiles – the grout lines. It does not stabilize your tile enough to replace proper installation methods. This is not what epoxy grout is intended for.
A couple of reasons for using epoxy grout include the durability, ease of cleaning, and its ability to withstand staining. It is not intended as a product to make a sub-par installation correct. [continue reading…]
One of the most asked questions by do-it-yourselfer’s is whether they should use caulk or grout in the corners. Industry standards state that a flexible material be used at all changes of plane. But! – if you ask a hundred different professionals you will more than likely receive fifty of each answer. While there are pros and cons of each, I am in the camp that uses caulk. That being the case, I will discuss using grout first. I’m backwards like that.
Using Grout at Changes of Plane
While the phrase “changes of plane” may sound a bit uppity or technical – it’s not. It simply describes the corner or edge of any surface that changes direction such as a corner, a wall to a floor, or a wall to the tub edge. Many professionals simply grout that corner as they do any other space between the tiles. There are a couple of things that must be taken into consideration before choosing this method.
Your walls and the framing of your shower must be absolutely rock solid. I do mean absolutely. Grout is a cement-based product and as such is not meant to flex. If your wall moves your grout will eventually crack – it’s that simple.
The space between the tiles at the change of plane must be large enough (for sanded grout) or small enough (for non-sanded grout) to be able to support the grout. That simply means that if you are using sanded grout you cannot butt the tiles against each other at the corner and expect to be able to force grout into it. It will not stay if the grout has no grout line to hold onto – if it is simply attempting to grab onto the face of the tiles at a 90 degree angle. There must be a grout line at the changes of plane.
You must decide you are going to use grout at the changes of plane before you install the tile. You can then make sure to leave a line for the grout as well as adding additional support for any spots that may move even the tiniest bit (which it should not do anyway).
If you have taken the above points into consideration and still decide to use grout in the corners – go ahead. The big advantages of using grout here is that it will match all the grout lines and it will never have to be replaced. So although extra care must be taken to properly use grout at your plane changes, the advantages for some people are worth the extra time. [continue reading…]
This is a question I get asked from time to time. The short answer is no, you should not. Although grout does not add to the stability of the tile installation (unless it is epoxy grout), you still need to grout it.
Why you need grout
A lot of natural stones, namely granites and marbles, are manufactured to be consistently sized. For the most part all the tiles are identical. This makes a lot of people want to install them without grout lines. Although in some people’s opinion butting the tiles against one another looks better than having even the smallest grout lines, it is not a recommended installation procedure.
Even if all the tiles look like they are the same size I can nearly guarantee they are not. Unless they are “rectified” they will differ, even if only a tiny amount, from tile to tile. Attempting to butt the tiles will result in a “jog” of the lines between them. The larger the area, the more those lines will run off. By leaving even 1/32 of an inch grout line you will be able to compensate for the difference in tile widths. [continue reading…]
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