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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My work partner and I do a lot of bath remodels and I would like to add to your original post.

Whenever we have a new stand up shower to build we leave grout lines for everything, (we like 1/8″ for a 12″x12″ and under) also we use 100% silicone (clear usually) in all of our corners after the grout has set. The grout sucks it up so you get some flexibility and a great bond that will last.

Clear paintable silicone is also wonderful to use at any spot where you might have a grout/paint border. It stops the grout from wicking the paint in and you can keep a nice straight line. Just some extra for you do it yourself era


Doug Thompson

Hi Floor Elf.

Please help. We have white 4 x 4 tile in our master bath and the grout seems where floor and wall (also tiled) are cracked and crumbling in spots. I’d like to scrape away the old grout and then re-grout, but I’ve been reading that “changes of plain” should be caulked. Is this correct? I know that eventually I’ll get more cracking, but in my opinion, grout will look better than caulk, at least in my situation.

Thank you in advance for any help or advice you can provide me.

Doug Thompson



Hi Doug,

As I stated in the fairly lengthy article above where you posted your question yes, it is correct. It needs to be siliconed or caulked – grout will crack. But you already knew that.



We have removed grout from a honed slate shower (with granite sills on two sides, tile under these) showere was previously all grout. One can see the crack on one vertical change of plane–however clearly there were leaks where walls met the floor and or sill met the tiles). Siliconiized acrylic was used for the entire shower as a fix…and of course failed. It just gets wet and washes out, rinse repeat. I have attempted to remove most of this and the contractor will re-grout.

Naturally I am nervous about using the siliconized acrylic caulk for change of plane. The folks (spoke to two different technical specialists) at Tec tell me one should NEVER use this product where floor meets a wall. Always use silicone. Along with no grout in the joint, no hollow spots (not sure what these are?)’ go DEEP (maybe trying to make sure we ar not just covering up the grout?)’ it’s to be a “rope” around the base, needs two edges to attach to.

That leads to the issue of, really? I don’t read that often and gosh it sounds hard to apply? But clearly the siloconized acrylic is not intended for this? My tiles from floor to wall do not overlap — in other words, they meet at their edge and floor tile doesn’t go under wall tile.

Grout has been removed from floor tiles and one tile (12″) up the walls and from underneath the sills.
Thank you!



Hi Sharon,

If by ‘leaks’ you mean there was actually a leak in your shower into another part of the structure then your tile, grout or caulk has absolutely nothing at all to do with it. Siliconized acrylic should not be used at wall/floor transitions. Silicone is what you want to use. It isn’t that hard to apply, they’re going to tell you everything they can think of to cover their ass. It applies just like the caulk.



Roger–Thank you!

And no, by “leaks” I meant through grout joints, not an actual leak –at least not that we know of!

That helps tremendously, duh, of course it’s just a CYA.



Hi Elf ; )

Im about to grout my first tile shower and am wondering about order of things. Ive got a siliconized latex caulk and fusion pro grout (both products from custom – so colors are a match). Im gonna fill all changes of plane with the caulk first and then once thats dried – start-a-groutin. Is that order right?

Im also wondering about the spot where the grout meets the caulk. Is this a weak point or will the grout fully seal up to the section of dried caulk?

Am I over thinking this?




Hi Andy,

You can do it either way, but you’ll get a better seal and bond if you do the grout first. The caulk will bond to the grout, the grout will not bond to cured caulk.



exactly what I did – and it turned out great. Thx!



Great site with great info. I have a granite kitchen counter 18 years old that looks perfect. Still shiny been though I abuse the heck out of it with cleaning products. The grout/caulk between the 4″ backsplash and counter needs replacing. Do you think a first timer is capable of doing this (me)? How difficult and do you suggest caulk? If yes, which brand is the best (I need a color)? Thanks.



Hi Marilyn,

Yes, a first timer can definitely do it. I suggest silicone. Laticrete and TEC both have numerous colors that can match your grout or granite color.


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