Let’s play “Myth Busters.” Everyone knows that it is important to keep the connections between tubs and its shower surround well caulked. I often find these areas recently caulked in an attempt to “spiff things up” for the sale. Take a look at this first picture. This is brand new construction----doesn’t it look “SAWEEEEET?” Don’t you wish you could lay a bead of caulk like that? Before you get too envious (you knew this was coming) I am here to tell you that the caulk should not be there. As commonplace as it may be----as seemingly logical as it may be----it is still wrong in many cases. Caulking this connection is fine if the wall is some sort of one piece sheet or enclosure, but with tile it should not be there. The grout joints are designed to prevent water from penetrating the wall but any small amount that does penetrate is able to evaporate out and/or weep out along the bottom. If the tub/tile connection is caulked the water cannot wick out through the bottom grout joint and moisture builds up and is able to feed the mold that eventually develops. I am sure you have all seen that grey discolored staining of the caulk that you would swear is “behind” the caulk----where it cannot be cleaned off? And you would be right---it is behind the caulk. The next thing that happens is that if there is enough water building up behind this area the water runs around the edge of the tub and down the walls behind the tiles “outside” the tub with the common resultant damage to walls and floors outside of the tub. Sometimes this damage is just from water not being corralled into the tub by the shower curtain, but when the same thing happens with a shower door in place, these other factors may be at play. These conditions also “complicate” the inspector’s moisture meter readings. So if you have a tile tub enclosure----keep the grout well repaired----but don’t caulk the connection and the enclosure will behave itself much better. Charles Buell
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And who is going to tell the builders to stop doing this? Also, about half my inspections come in with a recommendation for recaulking around the tub. Why would inspectors disagree about what would be just an obvious thing?
Hey I learned something today. I'm considering doing some DIY remodelling for my dad. So this tips are pretty helpful.
Charles - this is good information and thanks for sharing it about the caulking. I always learn something new from your posts.
Very informative...thanks so much for posting!
Charles - this is good information and thanks for sharing it about the caulking. I always learn something new from your posts.
That show is great - I cannot believe some of the things that they come up with to try! Great blog.
Charles - I'd still use caulk, one with a mildewcide. Because of the differences in materials (tub and tile) and the movement of the tub when filled, there will always be cracking in this area. While moisture penetration through the grout is possible, it's minimal, (I always seal the grout) and shouldn't present a significant problem.
Hello Charles,
As REALTORS we see so much of this and to this date, I do not recall anyone ever stating the error so clearly. And many home inspectors when calling it out, speak in terms of caulk and not grout. In San Diego, we are fortunate to have a company that actually specializes in " all things Grout" to treat the issue correctly and their company is aptly called " the Grout Doctor"
That's a good point and I'm glad I was listening. Now, off to the bathroom to see if I comply.
Hey Charles,
This is a great thing to know and you once again explain a common issue in a simple way-thank you. Question for you however, what happens when a "re-bath like" guy replaces my old tub with a stand up one and uses 5 different pieces to do it? The five pieces are as follows: one that is the actual stand-up shower (bottom), three that are the walls, and one that is the ceiling of the shower space. All the seals along the edges, where the individual sheets meet, are sealed with caulking. Should I expect disaster?
Hi CHarlie - I had no idea! thanks for the info :)
Thanks for the informative post. I would never have guess that the caulking doesn't belong there.
Donna, I would say that in my experience about 10% of builders, 10% of inspectors, and 10% of tile installers know that this connection should not be cauked if it is a tile installation. I did not know it myself for most of my incarnation as a builder. It will take some time to get everyone on board with this.
David glad to help
Sharon, you are most welcome
Terri, thanks and thanks for stopping by
Jody, yes, I often say next to being a home inspector that is the job I want :)
John, while sealers of the grout will help for sure it too has to be maintained and still some amount of water will penetrate and has to have a way out. Sealing the bottom with caulk in my opinion almost always sooner or later develops unsighly mold behind the caulk and can result in channeling of water around the edge of the tub to the outside.
William, this issue is not widely understood by any of the professions: builders, inspectors or tile installers. The problems that result are widely seen however.
Glenn don't be surprised if you don't---mine doesn't either :)
Joe, large multi-section enclosures should have all the seems properly caulked----or you will get all kinds of crud collecting and stuff growing over time. We are only talking about tile enclousures here.
Kara, you are welcome
John, most people are not aware of this.
Well done Charles. I knew that grout instead of caulk was the way to go. But I had no idea that the discoloration of the caulk was from water behind it. I learn something new every time I visit your blog. Thank you.
Craig, good job, you are a proud member of the 10% club :)
Charles - I did know this. And have seen mold develop behind caulk. And yes I wish I could spread a bead of caulk like that. Very informative post.
OH, well I'm glad I asked! Thanks Craig.
To caulk or not to caulk, that is the question...
I hope you're having a great Thursday,
Paul
Claude, thanks---it is a mean bead of caulk :)
Joe, I am guessing you meant me? You are welcome anyway :)
Paul, yes the real age old question---what the heck did Shakespear know?
Hmmm. Bummer. My tub is one of the bad boys!
Debi
Another great tip well illustrated Charles, thanks for keeping us walking the line.
That is certainly a new one for me. I've never heard this explanation. Hopefully, you don't write this up on many houses.
Debi, so is there mold behind the caulk?
Frank, it is such a thin line that caulk isn't it? :)
Barbara, I write this up differently depending on how much damage there is---or appears to be.
Mr Charles,
I am not a proxy error tonight. I am very pleased.
Nutsy
I have heard of fluid dynamics, but never fluid corralling! Cool concept! How do you do that? Head'em up! Move'm out! Head'em up! Raw fluuuuuuiiiid!
Sorry, couldn't resist...
When I moved into my house 12 years ago, I removed the cheap-o builder caulk and replaced it with 100% silicone with a mildewcide/fungicide. To date: no brownification! I did that because if the tiles are placed tightly onto the suface below and grouted, the very thin bead of grout cracks easily. Why? The builders don't use the latex amendment to the grout mix! I like grout as the bottom bead - as I did when I granited and splash backed my kitchen counter - but I used the additive!
The road less traveled can make all the difference. I heard that somewhere.
Very kindly,
Croakster
Jay I think tha approach "can" work as long as the grout sealant holds up and NO water ever gets through the grout and heads by gravity toward the bottom of the tiles---just a little riskier.
Good stuff, Charles. When remodeling for our abode goes into full gear, I think I'm just going to print out your blogs and put them in a binder.
And who is this Croakster fella? :)
Jason, croakster is just my rotund amphibian friend that pops in to croak about things now and then :)
OK Charles, So after the 29 warm and fuzzy, supportive comments already posted, I am going to be your first skeptic on this issue. :) ........This is quite the paradigm shift.
I am not saying you are wrong, but rather trying to grasp the concept. Maybe I can learn something?
But let me toss a couple things out, and see how you respond.
First do you have any technical sources that support "not caulking" the joint between the tub and the tile shower? It has always been my understanding that the Tile Council of America (TCA) has specified these joints to be caulked. I don't have the most current 2009 TCA handbook, so I can't look to see if anything has changed.
Secondly what I don't understand is what prevents the water from migrating into the wall through capillary action, when there is an absence of caulking.
Is there a difference in recommendations between the more modern (CBU) Cementious Backer Units and the ever so common shower tile adhered over drywall installation?
Also you stated that the reason not to caulk is to allow gravity drainage of moisture from behind the tile. With a properly installed tile shower wall, where would this moisture be coming from?
Thanks for reminding me that I don't know everything. :)
Harold, first of all there were a few "hints" of skepticism amongst the comments :) For years too I assumed that this joint should be caulked but after seeing so many problems with it being installed there I did some research and discovered why this damage was happening. All grouted tile joints accept water over time----this is why it is such a problem installed over drywall. Cementatious backer board is really the only accepted substrate for tiles in a shower enclosure and stops the damage to substrate so common with drywall----but does nothing to stop the small amounts of moisture that does penetrate over time. This moisture just needs a pathway out. Ever notice that little cut-out along the joint of a plastic shower base that is a weep hole for trapped moisture when tile is used with the base? It is the same principle with any enclosure where this small amount of moisture needs a way to weep out, evaporate out or run out. If the connection is caulked, one risks trapping this moisture behind the caulk. The better the caulk job and higher the grade of caulk the better the trapping. I see mold growing behind the caulk as pictured above too often for this to not be the case. With just a caulk joint---sure there is the possibility that it too will absorb some moisture but it can evaporate out---it isn't trapped. Keep the tile grout sealed as conscientiously as possible and the enclosure will behave itself just fine wiithout caulking this joint.
Very infomative post Charles. I like learning something new everyday. You are a great teacher.
Troy, hopefully we all are----hard not to if we are paying attention:)
Thanks for the response Charles. You spoke of research. Can you refer me to any documentation. Certainly if I were to recommend this to my clients, I would want something to back me up.
Mr Charles,
You are hanging by a thread on this one. I anxiously await your response.
Nutsy
So has Nutsy been traning for a space walk? .............
http://www.dailymail.co.uk/news/article-1256202/The-squirrels-love-stuck-coconuts.html
Nutsy, you are going to be in threads when that outfit goes off
Harold, great picture----however Nutsy's head is WAY to big to fit inside a coconut and it is just as hollow. Also, hand in their----I am tracking down that info for you. What I am finding out is that if NO grout is used then silicone caulk will be ok as it will fill all the way back to the underlayment and thus not trap moisture behind the caulk/tiles. It is only when the joint is grouted that it should not be caulked over.
Mr Charles,
It looks to me like Mr Harold, like me, has your number. Sometimes wiser heads prevade.
Nutsy
I'm proud to say I'm part of that exclusive 10%... now.
Thanks for the info!
Thanks for this great information, it answers a lot of mold questions when everything seems so ship shape and tidy. You are a fountain Charles!ems
Mind if I re-blog this entry on to my web site?
Reuben, I am sure you are always at least 90% :)
Ana, yes----very commone
Reuben, plese be my guest.
Done, thank you. http://www.structuretech1.com/blog/2010/06/bath-tub-caulk/
Good advice. Thanks
Aaron
You are on a roll, my friend. I have two showers that are caulked and they shouldn't be. You just added an item to the honey-do list. RUN!