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′.
This simply means that if you install tile in your living room and it is larger than 25′ or 30′ you need a control joint – period. It is non-negotiable. If you do not have it chances are likely that your tile installation will fail. The number one reason for tile installation failure (on a floor) is lack of proper control joints. You need them! *It’s either lack of proper control joints or improper coverage, there are conflicting views. Both will lead to a failure and both are installer error – both need to be correct!
You need them on wood, you need them on concrete, you need them inside, you need them outside. And no, that is not the beginning of a Theodore Geisel book. I’m simply trying to illustrate the importance of a soft joint in a large tile installation. Because it is. Very important.
Along with these control joints you also need to ensure proper perimeter spacing. This simply means that your tile around the perimeter of your room is not butted against the wall or framing. You need room for stuff to expand.
You don’t realize it but there are a lot of things in a structure which move – constantly. With temperature changes, normal construction shifts (settling), even sunlight causes enough significant heat to expand and contract structural elements several times a day. You absolutely need to allow for this movement.
If you do not allow for this movement your tile installation will not last long-term. Your grout will crack. Your tile will crack. Your dog will burst into flames. Your tile may ‘tent’ which means that there is so much pressure pushing two adjacent tiles together that the bond from the mortar will eventually fail and the two tiles will pop – literally – off the floor and tent. They will sit there right in the middle of your room looking like a little teepee. I tapped a tile once in an installation which did not have control nor perimeter joints and they literally popped – loudly – and tented.
Control joints also need to be installed above expansion joints in concrete – whether you use a membrane or not. A membrane will allow you to ‘shift’ the control joint in the tile over up to six inches (depending on which membrane you use) but it still needs to be there. If your concrete has a control joint it needs to follow all the way up and through your tile installation.
Most grout manufacturers make a matching caulk or silicone which can be used for these joints. When cured they match the color of the grout exactly or nearly so. You can tell it’s there – if you look for it. Don’t look for it. I understand that a control joint may change the look of your installation – you may not like it. I know. I get it. I don’t like them either. But you need them.
The photo at the top of this post shows a control joint through the middle of a tile installation. This is right after I finished installing it so the caulk has not yet cured – that’s why you can see it. Once cured it matched the grout color exactly. In my next post I will show you exactly how to prepare this grout line as a soft joint and install the caulk or silicone.
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Hi Roger:
I am moving along on the longest bathroom remodel in the history of man(woman) and I am preparing to lay shower floor and the bathroom floor. I have (surprise!!) another question. I need to leave a space between the wall and the floor tile to allow expansion. The Schluter site offers to sell me a product for all those joints, and I know there are others, but couldn’t I just fill the 1/4 space with the same caulk as used in a control joint? Or even unccolored caulk since it wont show under the baseboard, or where the wall tile meets it in the shower. Please advise, my dog is getting nervous.
Hey Sally,
Yes, you can simply leave a small gap and silicone or caulk that. You don’t need the schluter profiles.
Your dog should be fine.
Hi, Roger,
Do you know where I can get the proper kind of (colored) caulk to use as soft joints between ceramic tiles that I am laying on a concrete patio? I found a company that sells a product called Duo-Sil in many colors, but they told me it was too soft (Shore-A = 68) to use for a foot-traffic application and that they don’t have a product for that purpose. I’m not sure what specifications I need to be looking for or where I can find the proper product.
I really appreciate the help!
Karen
Hi Karen,
Latasil from laticrete and tec both are silicones approved for foot traffic. You can find either online or one or the other at most tile supply shops.
Hi Roger, great advice.
I’ve received varying advice on the following project at my house in South Florida. I have ~500sqft covered patio with a concrete substrate and 3 control joints spaced out about 10 feet. Also, the tile I want to install is a 6″ x 24″ porcelain tile that looks like a wood floor…so, I would have to stagger the tile. After reading your article, and the various posts, I intended to lay a crack suppression underlayment across the entire surface, and then add the soft joints in a zig-zag pattern over each expansion joint. Does this seem like a reasonable approach? I also considered first laying redgard, then the underlayment, but I didn’t want to spend the extra $$ for overkill that is not really necessary.
Just FYI, the house and floor is only 4 years old, and no visible spider cracks in the floor (yet) except within the expansion joint.
Any further advice you can provide is most helpful. Many thanks!
Hey Ryan,
The better option would be to turn the patter 90 degrees and lay the straight lines over the control joints. That way you would have a straight control joint right over the expansion areas. But if you need to have the patter installed in that manner then running a zig-zag control joint will work just fine. And it is my honest opinion that when it comes to exterior installations, especially decks, there is no such thing as overkill.
Roger,
You helped me a great deal with my shower project question last month. THANK YOU!!
We’ve got about 2 weeks left until our baby’s due (so any day now) and we’ve begun to pull up the nasty carpet in our walkout basement. By “we” I mean me and by “nasty” I mean, well, nasty. To my delight, under the carpet and matting I found 1) cheap linoleum from 1972 slapped to the slab with Elmer’s glue for adhesive, 2) a 1/8″-1/4″ crack in the slab essentially cutting my house in half, also 3) the discarded debut album “Whole Oats” by Hall & Oates (that’s how I knew it was 1972). Ha ha! I’m only kidding, of course! I don’t think they used any type of adhesive.
The height offset of the slab surfaces at the crack is very small, I’d say 0.050″, and the room is about 20′x20′. My question’s are:
1. Is there anything I can inject or patch to fix the crack? (probably not)
2. What can I do to keep the floor tile (12″x12″) from cracking in the future?
3. Any good experience with electric radiant mats? Besides warming the floor in our Michigan home, I thought they might help buffer the tile floor from crack growth. Thoughts?
Just ’cause I’m that kind of guy, I’m including some pics. First, the original tile under the carpet, and second, the broken tile showing the crack in the concrete slab.
Many Thanks,
Michael
Hmmm… I hope the forum allows some HTML, or at least links.
Pic 1
https://picasaweb.google.com/lh/photo/V4s9HHG7v4HFAcvCzcLkDPck1F_68r6y2nEg7kkfk60?feat=directlink
Pic 2
https://picasaweb.google.com/116602069561788745051/HomeImprovements?authkey=Gv1sRgCIi6_KC2_KmsRg#5682115447167651794
-Michael
Whole Oats, huh? NICE!
You can use a crack suppression membrane such as redgard (that was actually the initial purpose of it) and brush or roll on about three coats to 3″ or so on either side of that crack. I don’t use the mats – I always string the wire. I honestly don’t know how much it would help cushion it. I’m sure it would help, I just don’t know how much. As long as you use a crack suppression membrane over that you shouldn’t have problems with cracking tile.
Can I install 12 x 24 tile in a stacked bond pattern on a shower wall? It’s only a 48x34x84 high space and I would like to use large tiles for a modern look. Basically it would be two stacks on the long wall, then one centered stack with a 5″ stack on each side for the short walls. I read something somewhere (always dangerous, right?) that commented on potential problem with stability with large tile in that pattern. Thanks.
Hey Elisabeth,
Sure you can. I would suggest no longer visiting the site on which you read such misinformation.
The only problem you’re likely to run into with the large format in that pattern is that all manufactured tile is ‘cupped’ to a degree, which means the center is a tiny bit higher than the outside edges or corners. So when you use that pattern you’ll have the corners directly in the center of the adjacent tile – lowest part right next to the highest part. The NTCA now recommends that all large format tile in a running bond pattern be set with a 1/3 offset rather than 1/2, it helps minimize the differences. But you can do it however you wish – it can be done. And it will be just as stable (more stable, actually) than using 6×6 tiles.
Actually, I was asking about stacked bond, not running bond…..(don’t tell me this is another one of those web sites…??) so all the tiles would be stacked directly above each other and all the grout lines would be aligned, so to speak ( type….) so basically the cupping would create a slight undulation across the wall surface from stack to stack? My real concern was with the tiles slipping down the wall because of their weight – but if I use spacers, it should be OK? ( not trying to answer my own question, just hoping for confirmation) Wish I ‘d found your web site years ago….for the great advice as much as for the laughs. I’ve always used the expression ” my head will burst into flames” but never imagined my dog was at risk. :o)
What type of ‘websites’ would that be?
If the tile is not offset the imperfections due to cupping of the tile would not be noticed. As long as your bottom tile is either fully supported or already cured and you use spacers you won’t need to worry about tile sliding down the wall at all.
Thanks. So by “already cured”, I should set the bottom course and let cure before moving up the wall? (Makes sense……what a concept, huh? )
Yup, that’s what I mean. Set the first row then set the rest the next day. It gives you a solid base to build up from.
Thanks. Next question- do I have to have a curb on my shower or can it be curbless like a wheelchair accessible shower? My existing bathroom has a hideous fiberglass enclosure that has got to go. I would love to have the new tiled shower without a curb to stub my toe on every morning. Since the floor joists and subfloor are already in place, I’m thinking it is more difficult to retrofit this than it would be to build it from scratch to get the slope to the drain properly set. I know there are gasket type collapsible dams that can be glued and sealed to the floor, that you can run a wheelchair over but don’t especially want the institutional look. (i’ll be there soon enough……) I have seen European wet rooms with no shower separation, but don’t know how that flooring is sloped. What do you recommend?
Doing that requires rebuilding the joist structure and shoring up the present floor since you’ll need to drop the joists or cut them down a minimum of 1 1/8″. The European wet rooms are designed from the start with sunken areas and recesses for any areas which need to be sloped. Retrofitting it is a fairly large undertaking.
Great site! It is answering many of my questions. I am installing almost 500sqft of 12 x 12 porcelain tile in my kitchen. We are doing it for our landlord for a break on our rent. We pulled out 1970′s glued down industrial carpet (yes, in a kitchen, gross). I spent a week scraping off the remaining glue and pad. The floor has minor level problems and normal cracking for the age of the house but it is flat. I suggested a membrane but the landlord just wants to mortar right over the old concrete floor. It is his floor and I am tired of convincing him otherwise. The kitchen is 25 feet long (very big). We are doing a brick layout to help break up the length. It sounds like we need a soft joint but how do you do that with a brick pattern. The width of the kitchen which is 16 feet. Do I do it that direction?
Any other suggestions for this floor are helpful to. oh, and we are thinking of 1/16″ grout lines.
Hey MollyMo,
With a running bond (brick) pattern you do have consistent, straight grout lines in one direction – put your soft joint there. Unless your offsetting them in the short direction, in that case you can simply follow one grout line back and forth from one side to the other.
You’ll want to check the flatness of those tile, especially using a 1/16″ grout line. All tiles are ‘bowed’ to an extent, just make sure it isn’t bowed enough to leave considerable lippage when placing the corner of one tile next to the center of the other.
I’s totally unaware about soft Jointing. It seemed to me something like joining the tiles lightly. But, I once came to no this is not like this. Then I read this post and acknowledged clearly about what is a Soft joint and how to install it effectively. Indeed, your other posts are also useful and informative.Keep informing Roger.
Glad I could help Alen.
Wow… That was a quick answer . Are you an elf lord or what .
Well , there are few reasons it is important to know about understanding guidelines or using guidelines .
Any other literature , other than the TCNA guidelines ?
Considering 2 large areas of 1000sf , same level floor , one installed over mud bed with modified thin-set and the other on plywood with Ditra , both with porcelain tiles , how large the soft joints should be ? Is the width important ?
I am not talking about movement or expansion joints . Because there are differences in between movement joints and soft joints. How much of movement is expected in those applications and where is situated?
What are the considerations for them ?
As you describe them , with the must importance , I am really curious to have your understanding on using them .
Roberto,
I understand your question although I’m a bit confused as to why you are asking it? You describe two 1000 foot floors with different installation methods, which would mean different placement, location and size of expansion joints – each installation dictates different methods. You are asking me about other literature – other than the TCNA guidelines???
The Tile Council of North America ‘guidelines’, as you refer to them, are the minimum installation standard as far as general tile installations as a whole are concerned – I’m unsure what else you would be looking for? Each state, county, and even city may dictate their own standards, but rarely do. As far as ‘guidelines’ for tile installation are concerned here in the US – the TCNA is not the guideline, they are the standard.
Maybe you’re talking about the American National Standards Institute? The NTCA standards are all based around, and take into consideration the ANSI standards. If you follow the NTCA standards, the ANSI standards are, in most cases, covered.
As far as how much movement is ‘expected’? C’mon, you should know as well as I that is a question that cannot be definitively determined without at least an in-person, hands-on examination of the particular area on which it is to be installed. Not sure what you’re fishing for, here.
The bottom line is this: I created this site for Do-it-yourselfers, we are currently discussing a subject that doesn’t really apply to anything a diy’er would tackle. If you would like to discuss the professional applications and understanding of any of the TCNA standards, or any other that you may be implying about, please join us at the John Bridge Forums in the Professional’s hangout and you will not only get my take on this stuff but the opinion of several of the country’s best installation contractors as well. That would be the place to discuss matters such as this, not the comment section of an article I wrote for diy’ers tiling their bathroom floors.
Fair enough.
I will for sure get there.
As far as I understand , you tell that it is a must to have them – soft joints – .
Aside from guidelines or recommendations , what are the bases of having them ? Do you have any literature which explain how to make them and why you need them , regardless of your situations or layouts ?
Roberto-
The TCNA standards for movement joints – vertical and horizontal – are covered in the TCNA handbook under methods EJ171 – A through I. There are ten standards in there which describe nearly every scenario. As a professional you really should get a copy of this handbook – every standard that I state and methods I describe are covered in these standards.
The methods I describe when I write something like this – especially when I emphasize the need for these things in this manner – are not simply my personal opinion on the matter. While I do post things in which personal opinion do come into play – such as the running bond corner joints on which you commented earlier – I always state that they are an opinion and there may be more than one way to do it.
While the methods in this standards handbook do describe what is needed, when, and proper methods of different installations it does need to be translated into something which normal people can understand – that’s what this site is about. If there is anything here that you are questioning it will be in that handbook. As a professional you should be able to interpret them with no problems – get yourself a copy, it’s invaluable.
Do you need a control joint on walls?
Hi Cliff,
You do not need control joints on interior walls unless they are over 25 feet long or high. If they are larger than that – yes. I didn’t mention it because that would be an awfully large wall and most people don’t even have one wall that large in their house without any windows or openings in it. If it is one solid, non-interrupted wall over 25 feet then yes, you need a control joint on it.
Exterior walls need control joints as well every 8-12 feet. Interior walls exposed to direct sunlight DO NOT need the joints every 8-12 feet – it’s because of the wall substrate and the fact that it has open space in the wall cavity behind it. Interior only larger than 25 feet.
Great question – thanks!
So how do you leave a control joint for on-point installations if the control joint in the concrete below is perpendicular or parallel to the walls? I’m not doing such a thing – just curious. Do you do the control joint in a zig-zag pattern, or do you have to cut the tiles in half so that the tile control joint and the concrete control joint are aligned?
Hi Nicole,
The technically correct answer is to cut a saw joint directly above your control joint in the concrete and fill it with caulk or silicone. Yes, it looks like shit, and no, the standards don’t care.
I don’t do that. If I run into that situation I will use a flexible crack suppression membrane as far out each side of the concrete joint as possible, then I use ditra as my underlayment, then I zig-zag it. Technically correct? No. Ever had a problem with it? No. Ever will? Possibly. In which case I will replace the floor, do it technically correct, and call it a very expensive lesson learned. But I don’t think that will ever happen. I leave enough of a perimeter joint and the zig-zag patterned control joint which, short of something like a mall or airport, should give the tile installation more than enough movement ability.
Excellent question!