Caulk or Grout in Corners?

by Roger

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.

  1. 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.
  2. 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.
  3. 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.

Using Caulk at Changes of Plane

There are several advantages to using caulk in corners and any other area where there may be a plane change or where tile meets another material such as your bathtub or sink.

  1. Unlike grout you are able to use caulk in a corner where tiles are butted against each other. It will stick to the face of the tile rather than needing a space between the tiles to grab.
  2. Caulk is flexible. If there is any movement the caulk is flexible enough to move with it and remain in place. It will not crack out or fall off.
  3. Caulk is waterproof – grout is not. Water will collect in corners such as where your tile meets the tub more than it will on the face of the tile.
  4. If your caulk does crack out or need to be replaced it is easily done.

The only two disadvantages to using caulk instead of grout are that you need to periodically remove and replace the caulk and, depending on your choice of grout, you may not be able to find a caulk that matches exactly. The first reason I consider to simply be regular maintenance and the latter is less of a problem since most major grout manufacturers sell matching caulk.

When to Use Grout

The only time I will use grout for a plane change is when I am using epoxy grout. Epoxy grout is bulletproof! OK, maybe it’s not bulletproof but you can hit it with a hammer a couple of times before it chips. (Don’t do that.) If you are using epoxy go ahead and grout the corners and changes of plane as well. Although it is not flexible it will grab the tile well enough to prevent it from splitting or cracking out. Precautions must still be taken but the Epoxy is strong enough to withstand normal structural movement.

How to Decide

Given the above parameters I believe caulk to always be the best choice. What you must understand about tile installation is no matter where you are installing the tile, it is always a structure that moves, no matter how minutely. Concrete moves, (the ground beneath it) that’s why it has expansion joints – to control where the movement goes. Most shower installations are over a wood structure of some sort. Whether you have drywall, backerboard, or a membrane, if you go far enough behind the tile, you’ll find wood. Wood moves, it’s just a fact of life. Humidity, weather, even the structure’s foundation all affect how much it moves. By taking proper precautions you can minimize the movement, but it’s still gonna move. Taking structural movement into consideration caulk is, for me, the logical choice.

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Nichole

Hi Roger,
I’m a DIYer and just finished installing slate tile above the bathtub. I grouted and left the corners empty to caulk, however, given the uneven thickness of the slate, I have sections of the corners that have a larger space. I ended up using 1 3/4 tube filling one corner alone! Given this, I went to the local tile store where they reccomended pulling that caulk, grouting the corners, and doing a layer of caulk over that – ugh! I just pulled that caulk (scraped still wet caulk) but am thinking this may have not been the best advise as I don’t know if grout will stick after having the caulk in there. So, if I go back to just caulk, can it be that thick and ever dry? Or should I let the remnants of caulk dry and do the grout/caulk combo? Didn’t really think I could be so inept!

Reply

Roger

Hi Nichole,

Go to your local big box store and get some backer rod. It is a cylindrical foam that you stuff into the gap to fill most of it, then you just silicone right over it.

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RK

Hi,

I came across this site and I’m hoping you can help with a tile problem. I have a walk-in shower with a stone tile floor and ceramic tile walls. From what I can tell, that joint has some kind of sanded caulk, but I don’t know what kind. The home is about a year and a half old and the caulk is separating from the wall tile. Assuming I can find a replacement caulk, what kind should I look for, and how do I apply it so it doesn’t separate again (at least not so soon)?

Any help would be appreciated – thanks!

Reply

Roger

Hi RK,

It needs to be removed and you should replace it with silicone. If you google laticrete latasil you will find silicone in nearly every grout color. The silicone will retain it’s elasticity and won’t pull away from the tile, acrylic caulk dries out and pulls away (as you already know).

Sorry for the delayed response, my spam filter went ape shit last week for some reason, I just found your comment in the spam folder, I hope the answer found you in time.

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Jeff

Hello Roger,

My shower is tiled floor to ceiling. Along the bottom of the wall at the floor there is some cracking (just a few small spaces). What is the best to fix this problem? Also entering the shower is a marble “step” that overhangs a bit into the shower. Under it is a little area of tiles. The grout attaching the marble and the tile is coming out in chunks. Should I just pull the rest out and re grout it or just fill it with caulk?

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Roger

Hi Jeff,

It sounds like both areas you are talking about are changes of plane and they require silicone or caulk, not grout. Silicone can compensate for differential movement in the different planes, grout just cracks. You need to remove all the grout and replace it with silicone (ideally) or caulk.

Sorry for the delayed response, my spam filter went ape shit last week for some reason, I just found your comment in the spam folder, I hope the answer found you in time.

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Russ

Hi Roger,

I just installed 3″x6″ subway tile as the backsplash and wall decor in my kitchen (stacked 6 rows high to the underside of the cabinets). Unfortunately, I neglected to put spacers at the bottom where the tile meets the Corian counter top. The tiles have a continuous recessed edge for grout lines, so they are all butting up directly to one another. I am concerned there is no space – how likely is that to become a problem? The job is done except the grout/caulk, so if the chance of problems is lower than 50/50, I will leave it and hope for the best. If it is very likely to become a problem, can you please suggest how I might approach making a correction? Thanks!

Reply

Roger

Hi Russ,

I would leave it. Being only 18″ high you don’t really have a lot of space that will be creating pressure with expansion. It’s not ideal, of course (you already knew that), but if you use silicone at the bottom you should be just fine (grout will definitely crack out of there).

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Ross

Hi Roger,
I feel silly asking…I want to caulk the corners in the shower but the only “bath and kitchen” colors are white and almond. My grout is gray. “Pewter” if I’m saying it with my pinky finger in the air. I found a light gray but it is “window and door” silicon. Will the “window and door” be ok in shower? (GE SILICON II)

What caulk are you using that you mentioned has many color choices that will do well in shower?

Thanks man. -ross

Reply

Roger

Hi Ross,

It WILL work, but I think Laticrete #90 light pewter 100% silicone would work better – and match better. Just google that, there are several places online you can purchase it. TEC also has 100% silicone in all their grout colors.

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Carol

I read your information on waterproofing a shower. It was helpful. Thanks. I will use cement backer board and one of the paint on products. The thing I don’t understand is what to do where the backer board meets the preformed shower pan. If you caulk between the tiled wall and the shower pan, then if any water has seeped through your caulk and drips down, it won’t have any place to go, right? If you don’t caulk, does water creep up behind the tile? It really isn’t clear to me what you are supposed to do at this juncture.

Reply

Roger

Hi Carol,

You silicone between the backer and tub, you silicone between the tile and tub as well, with weep holes.

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Tim

Hey Roger I too am a tile contractor with more than thirty years experience, primarily, (lately) in high end custom homes. MOst of my work involves…no big surprise…kitchens and bathrooms. I started using TruColor grout by Bostik a few years back and now it is my grout-of-preference in almost every instance. I have successfully used it in plane-change corners many times, with no call backs yet.

TruColor (No, I don’t work for Bostik nor do they…..” is a pre-mixed, urethane based premium grout. It has a LOT of good qualities and a few not-so-great ones. It is very easy, and VERY quick to apply, you basically grout less than 10 square feet at a time, knock off the excess with the edge of your float, clean it ONCE with a very dry sponge, and move on. You’re done.

It is ALWAYS exactly the same color, unlike portland cement based grouts which can have their color washed out by overzealous sponging.

Biggest advantage, to me, is that it always stays ever so slightly flexible. I grout vertical as well as horizontal plane changes with it and the results have been flawless…at least for the last four years or so that I’ve done so. I have attempted to use Bostik’s own, “color matched” siliconized color matching caulk in the past and all of the traditional shortcomings of regular caulk apply. In my experience, these “siliconized” color matching caulks, regardless of their manufacturer, are far inferior to any pure silicone caulk, which only comes in a very limited number of colors.

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Bonni

Hi-
Can you please tell me whose responsibility it is to caulk around the tub for a new installation? My bathrooms are brand spanking new and the grout is already (after 3 uses) coming out from the wall/tub intersection. I just noticed that no one bothered to caulk around the tub. I used a tile installer for all of the tile and a home repairs guy (not very good) for the rest of the reno. Who should have done the caulking???
Thanks!!!

Reply

Roger

Hi Bonni,

Your tile guy should have done it. And there shouldn’t be any grout in the wall/tub transition, that should be silicone or caulk only.

Reply

Jim

Roger,

Great news..My bathroom restoration project has had a 1rst birthday party! Even better news is that I am nearing the grouting stage.

If I caulk my corners, should I caulk first or grout first? If I am supposed to grout first, how do I keep the grout out of the later to be caulked lines?

Thanks.

Reply

Roger

Hi Jim,

You can do either. If you grout first just scrape any residual grout out of the corner before it cures.

Reply

Sue

Hi Roger,

I like to change the sealing around my kitchen faucet every two years (build up of something black occurs, and when removed, a fishy smell.) What do you think we be a good sealant but very easy to remove? In my experience, silicone caulk takes forever to properly remove, and I don’t want to damage my granite nor the chrome finish on the sink faucet with an accidental scrap and the back splash to so close to the faucet, that it’s very hard to scrap behind it. Basically, I want something waterproof/sealant, and easy to remove and replace. I think grout is out of the question, and I’m not sure if latex is any better than silicone to remove. Any ideas?

Reply

Roger

Hi Sue,

Silicone is your best option. You don’t have to scrap it, you can get the largest portion of it out by scraping, but you can just rub your finger on the remaining little bits to remove it. It lessens the possibility of damaging anything. Anything that is waterproof will, by nature, not be easy to remove – or it wouldn’t be waterproof.

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Tony

Roger,
I am a GC from MA and have an issue with a tile installation 5 years ago that we are now dealing with. The job was to remove a fiberglass tub, existing floor tile, install an Americast Tub with a new porcelain wall tile surround with antique white grout. We shimmed out the studs and installed hardibacker over flange. We tiled 3/16″ from tub base and then installer grouted all areas. We got a call a month after completion that paint outside of tub on lower wall was flaking and water was getting onto floor. At the time we thought it was a shower curtain issue and owner bought a sliding shower door and we never heard from them again until this summer 4.5 years later. We were told that the tub was still leaking but they didn’t want to be a pain to us. Great people but hard for us to fix something when we don’t know. We should have followed up after shower door company installed looking back at it. Anyways, we used a hose from outside to give it a leak test and both the shower door leaks as well as the corner tile grout 18″ up on mixing valve side. Our original solution was to remove all grout on tub/tile and vertical inside corners and use latticrete silicone color match but owner does not like the “shininess” of it. My next solution is to remove those same areas and use SpectraLock in those same spots. After reading your site, I will use weep holes 1″ behind sliding shower doors and make sure glass door guy removes silicone from inside track and only have it on exterior. If this does not work, we can re-grout all with spectralock as another option or just simply start over and waterproof hardibacker like we do now on all jobs (we started that about 3.5 years ago on these applications and we almost always use Spectralock unless the owners refuse to pay the extra or want some different color/look). Any advice/thoughts on our plan? Thanks

Reply

Roger

Hi Tony,

It sounds like that would be fine, but the silicone would be a much better option due to differential movement on the walls. Have you asked about sanded caulk? It isn’t shiny, she may go for that. You may also want to pull the screws out of the frame and squirt silicone into the penetrations and re-install them.

Reply

Tony

Thank you for the quick reply. BTW, love this site! The tile installer actually used sanded caulk after grout at tub/tile intersection but not on vertical wall intersection. Now, I am not sure he waited for grout to dry properly and/or if that is kosher to do anyways (caulk over permagrout). If it is ok, can I use sanded caulk over vertical corner grout now before I go through with grinding out those corners? The tub/wall intersection is already free of grout/caulk now. For the record, I am not excited about sanded caulk as I am not sure it will pass the leak test like spectralock or silicone but would love to hear your input.

Reply

Roger

It is not there to prevent leaking of any sort. Your shower should be absolutely waterproof before tile is put on the wall. The silicone or caulk is there for purely aesthetic reasons. The reason silicone is better is because it won’t dry out and lose elasticity as quickly as acrylic caulk. You need to remove all the grout from the changes of plane before you caulk it. Caulk or silicone over grout is useless, the grout will still crack and break the bond of the sealant. It should be only silicone or caulk in all those areas, no grout at all.

Reply

Denise Tomion

Hi Roger,
My sanded grout was cracking where the different planes intersect. I have taken MOST of the grout out from those spaces, but I cannot seem to get every little bit out. Can I still put a sanded caulk on those corners/edges?
Thank you,
Denise

Reply

Roger

Hi Denise,

Yes, you can.

Reply

John Walls

I like your idea of using caulk in corners, instead of grout, to allow for wall movement. I have a few questions and would appreciate your advice on the following:

1) If you used a color matching silicone caulk (Latasil, or even GE silicone II in very limited color choices), wouldn’t that last a lifetime? So the caulk maintenance issue would go away? If not a lifetime, what is a reasonable expectation for it to last?
2) Is sanded caulk available only in latex?
3) If you used epoxy grout at a plane change, wouldn’t that subject your tile to stresses from eventual wall movement? Like maybe the grout won’t crack, but the tile (or underlying thinset) will (somewhere in the plane maybe)?
4) I thought tiles were not supposed to be butted together in the corners (for the same reasons as in 3) above). Shouldn’t you leave a 1/16 to 1/8 gap regardless of our choice to caulk or to grout?

Reply

Roger

1. Silicone is not a permanent product, it is meant to be periodically replace. 5-7 years is average.
2. As far as I know, yes.
3. It depends on the construction of the shower, but for the most part yes.
4. They are not. And yes, you should leave that gap. I’ve never stated otherwise as far as I know.

Reply

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