A common misconception about tile and grout is that they are waterproof. Once you install tile in your shower you have a big waterproof box that will last forever. Ummm, no.
Tile and stone (as well as grout) will actually retain water. How much water it retains is directly related to the density of the tile. For instance, porcelain tile is much more dense than travertine. This means that travertine will retain more moisture and allow more water to seep through to your substrate. If you happen to have travertine in your shower – don’t panic. As long as it was installed properly it will be fine.
So how do they figure this out?
When a specific type or brand of tile or stone is manufactured for production, the company will determine its density. There are four different categories into which each tile may be placed.
This is determined by weighing the particular tile, submerging it in water for a period of time, then weighing it again. The difference in the two weights determines the density or absorption of that product. Basically how much water it holds. It will then be placed into one of the four categories.
- Non-vitreous: These are tiles that absorb 7% or more of its body weight. These are for indoor use only, normally on vertical surfaces such as backsplashes and wainscots.
- Semi-vitreous: These absorb between 3% and 7%. These are also for indoor use only.
- Vitreous: Absorb between 0.5% and 3%. These tiles may be used for interior and exterior applications.
- Impervious: These are the most dense (porcelain) and absorb between 0.001% and 0.5% of their weight in water. They are suitable for all applications.
Depending upon where you intend to install the tile you may need to consider this. In most cases it’s not an issue. Only in the most extreme or unusual circumstance will you need to take into account the category of your particular tile. A tiled patio in Alaska, for instance. If you have a tile that absorbs a considerable amount of moisture and it freezes, well, you’re gettin’ a new patio.
The biggest factor to consider is the amount of water to which the tile will be exposed. (Along with the possibility of freezing, of course.) For anything up to and including a regular shower, it isn’t necessarily an issue. These applications, using proper methods, should be at least water resistant before a box of tile is even opened.
Why is this an issue?
With any tile application, the durability of the tile will be only as good as what is beneath the tile! Let me say type that again – that again.
If you have a wall in your shower with just plain drywall and you stick your tile to it, it may look good for about a year. It may look good for much longer. But, if moisture gets behind the tile (and it will) through the drywall, to the framing studs, well, you’re screwed.
Your framing studs are (most likely) just simple 2 X 4′s. If even a minute amount of moisture from your shower reaches it all hell’s gonna break loose. Common studs will do what we call “wick” moisture. It is aptly named because it acts just like a candle wick (tile guys are simple folk).If you place one end of a candle wick in water the other end will be soaked in short order. Wooden studs do the same thing.
Think of it as a water highway. The water will simply continue along that same path until it finds something else to soak into. That something else is more wood. When wood gets wet it . . . wait for it . . . swells. Normally that swell has only one place it’s going – right against the drywall and into the back of your tile. Tile’s will crack, grout will crack, your patience will crack, and the end of the world will be right around the corner. You get the idea.
This is not (normally) a subject that needs to be considered when installing tile on your floor. A shower (or other wet area) is unique in that it is subjected to a great amount of water on a regular basis. Unless your kitchen is a swimming pool you really don’t need to be that concerned about it.
Just understand that tile and grout are not waterproof so care needs to be taken to eliminate as much moisture from the surfaces as is realistic in any given application. You know – don’t make your kitchen floor a swimming pool.
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Add a Brilliant Retort
Add a Brilliant Retort
Roger,
We are in the final stages of finishing our shower project. The shower pan is from KBRS, the tile we are placing on the floor is cut stone. Should we seal it or not? If so what do you recomend? We will be using the spectraLOCK Pro grout.
Thanks in advance for the help!!
Hi Jean,
Yes you should seal it. I prefer Miracle Sealant’s 511 impregnator for most stone. Since you are using spectralock you should seal it before you grout.
Good day Roger
We have two problems which need some attention and your advice would be very welcome, please.
#1 The floor surrounding our toilet is already tiled with a non slip tile – feels like sandpaper to the feet – very rough indeed. So rough that a mop cannot clean it without losing its head.
#2 We have a young man in the family who has learning difficulties and one of those difficulties is using the toilet cleanly! He tries very hard but most times fails. Need I say more
The result is that our floor smells because we cannot clean it properly
I am going to retile with smoother tiles so that washing will be much easier.
From reading your advice so far it would seem that grout is NOT to be used.
Would you suggest using a silcone mastick to seal between the tiles?
Thanks in advance
Quentin Foulkes
Hi Quentin,
I have never, ever recommended that grout not be used. Maybe I was unclear in a response to somebody, or talking about stacked stone, or…? I try to make it clear that grout it always REQUIRED in any tile installation.
For your particular installation I would recommend epoxy grout, specifically SpectraLOCK by Laticrete, or a urethane grout (keep in mind this takes about a week to cure enough for your particular requirements). Either of those are stain-proof and easily cleaned.
Any silicone-based product is going to dry out over time, which will eventually lead to lost elasticity in the product. Once that happens it will compromise the bond of the product to the tile and it will no longer be sealed. You will have tiny spaces between your grout and the tile, which will lead to all sorts of different issues with cleanliness. Those products will not be suitable for your installation.
Hope that helps.
Good day Roger
Thank you – really helpful
Sorry I should have said that the ordinary grout that is porous would not be a good idea.
So much to learn and that is for us adults – imagine what our young fellow is trying to cope with.
Your advice is much appreciated. Thank you
Quentin
Roger, We are n the process of selling our home and during an inspection some questions were raised about the possibility of behind tile moisture in a shower. A moisture meter (Delmhorst Navigator Pro)
was used to determine that there is under – tile moisture content in the tile floor substrate. I’ve done a bunch of on-line research and I see that this is likely a normal side affect of a tiled floor. We have removed a section of drywall from the ceiling in the floor below to inspect the wood subfloor and all appears to be dry, although actual wood moisture meter readings have not yet been taken to confirm. It does in my mind confirm that the liner pan is functioning properly. The same instrument was used to determine that high moisture readings were measured on the wall tiles about 2″ above the floor level. At 1 foot above the floor level the moisture meter read that the substrate was relatively dry. I’m curious if you could comment on whether high moisture readings in these areas should be considered as a defect or if they are normal for a tiled floor. I’d also be interested in your opinion (if you have one) on whether moisture meters used in Scan mode (not pin mode) are an accurate way to assess under tile moisture levels.
Thanks very much in advance for any advice.
Hey Al,
That is completely normal in a shower floor. Scan mode is about the only way to scan a shower without possibly compromising the waterproofing. In my experience they are fairly accurate.
Our bathroom remodel was finished 2 months ago. The 3 shower walls are wicking water–the first row of tile on the lower part of the shower wall is darker and has also developed a fine line/crack in places above that row of tile.
All work was done by veteran tradesmen who have done quality work in our area for years without any problems. We visited the job site daily and feel confident that the work was done correctly.
The new shower was framed on a terrazzo floor. (House was completely gutted. )The shower pan was made by the tile installer. He used durarock on the shower walls. The 3 shower walls are tiled with large subway style ceramic tiles. The shower floor tile is a mosaic which was made from the same tile used for the shower wall. The tile was broken up and set in a design by the tile installer and then he grouted it. He has done this type of shower floor many times without any problems developing. He does high end installations and great care was taken while doing this job.
However, he is not sure why the shower wall tile is wicking up water. His first thought was that because of the floor tile being a mosaic made of broken pieces of tile then perhaps there is a higher ratio of exposed grout for the water to penetrate than in a traditional floor. Therefore perhaps more water is seeping into the shower pan than usual. (He doesn’t think the fine crack line above the first row of tile is causing the water to go down behind the tile. The crack is not consistent around the whole first row–and all of the first row of tiles are darker.)
Could the water be penetrating where the wall tile meets the floor tile?
We have stopped using the shower and are letting the shower dry out. (It is 4 feet x 5 feet.)
We love the mosaic pattern on the floor and it took days to install. (Which equals $ as well.) I am hoping there is something we can do to diagnose and fix the problem without tearing the whole thing out. Do you have any suggestions of where to start?
(I know I have said this before, and that no one is perfect, but the tile installer has always done superb work in our area and has tiled for over 25 years. He has done other work for us before and there is no signs of any problems in the rest of the house where he has installed tile.)
We are all scratching our heads on this one–including the general contractor, engineers, etc.
Any insight is helpful. I have photos if that would be helpful.
Hi Ellen,
You have told me a lot about the tile but nearly nothing about the substrate behind the tile other than durarock on the walls. Your waterproofing and the proper channeling of water is completely dependent upon the substrate and underlying structure – the tile and grout line size actually has very little to do with it. While larger grout lines will allow more moisture behind the tile it really makes very little difference in how the water is channeled into the drain.
Water will get behind your tile – always. Tile and grout are not waterproof. The key is being able to control how the water flushes through the shower. Durarock is not waterproof, it is merely water stable. It will not disintegrate or fall apart when wet but it does soak in water and can, in fact, wick water.
What all this means is that to give you a reasonably accurate answer as to what is causing your problem and why I will need as many specifics about the underlying structure, method of wateproofing, layers and layering order of the substrates behind your tile.
At first thought it sounds to me as if your weep holes in the drain may be clogged preventing water in the top mud deck from draining, which means it will back up to the perimeter of the walls. Once this happens it really has no place to go and will continue to climb from the floor up the wall, especially if the wall is wicking the water. Is your cracking more prominent on the walls closer to the drain (if you have a wall closer to the drain) or in the center of the walls more than towards the corners? If so that would probably be my guess. As the water backs up the liner from the clogged weep holes it will reach either the closest walls or the center of the walls before the corners.
Was there pea gravel or spacers or anything placed around the weep holes before the final mud deck? Is there a pre-slope beneath the liner? How are the walls waterproofed – cleavage membrane (moisture barrier) behind or a topical membrane in front?
Thank you so much for the prompt reply. I will contact the installer to get more of these details. Meanwhile, would sending you photographs that were taken at various stages of the shower remodel be helpful to you> If so, where should I send them?
Thank you again for your help with this.
You can send me photos at Roger@FloorElf.com
Roger: Thank you for your web site. I am doing research on the easiest way to “seal” an old tile/grout installation. My bathroom needs complete remodeling, so I’m looking for a way to make sure that water goes through the drain and not onto my failing shower pan.
Is there a dri-loc type substance that I can “paint” over the tile and grout that will be impervious to water? Or am I stuck grinding out the grout, putting in new grout, and crossing my fingers?
The tile is ceramic and I’d prefer not to use too many harsh chemicals.
Thank you in advance,
-John
I forgot to add that I don’t want to do a full remodel now, just keep it from leaking for a while until I figure out what I need to do (either hire it out or do it myself.) Thank you.
Hey John,
Sorry, there is no product which can be applied to the face of the tile which will make it waterproof. The best you could do at this point would be to use a topical sealer or epoxy grout. Either of which will slow water absorption, but will by no means make it waterproof. It may hold you over until you can replace it, though.
Thanks Roger for the answer. I wish there was an easy, temporary substance to apply. Just trying to hold off on ripping up bathroom and getting a new shower pan. Thanks again.
Hello…..I’m tiling a wall with 12″X24″ Porcalin tile. We are puttin in an ‘mosaic’ tile part way up. (They are 4″x1/2″ strips matted to a mesh backer. I’ve cut them into 4″x12″ sections)When we try to set the mosaic pieces, they slide down the wall. I was told this occured because I used too much thinset (3/8 trowel). If I go with a small v-notch trowel for this smaller tile, I still have to go with a deeper trowel for my main tile. This will result in the two tiles being uneven…..any ideas?
Hey Kevin,
Yup, read this: Setting different thicknesses of tile. Your tile is sliding partially because of the amount of thinset. Using a substrate behind your mosaics allows you to use the same trowel for everything and build it out to wherever you need it.
Thanks for that link…..What size trowel should I be using for my main tile (12″x24″)? Is there a greater chance of those tiles slipping with a larger trowel……could I go 1/4×1/4×1/4?
You are letting the possibility of sagging dictate the trowel size – stop doing that.
Unless you are using a non-sag mortar your tile will slip or slide down the wall, it happens every day. You want to start at a solid base and work up using spacers and/or wedges to prop the next row above it. Think about it like this: Your tile is going to slip down the wall if you don’t prop them up there for a total of about 24 hours – your tile will need to bond to that wall for 25 years or more. Be more concerned with getting enough thinset and a good bond rather than the tile slipping as you install it. You can always prop up the tile as you set it.
12 x 24 is a large format tile. You need a larger trowel – 5/16″ or 3/8″ is standard. It will give you a better bond and ensure full coverage. That is why I use things like kerdi or 1/4″ backer or another substrate on the back of mosaics when installing them into a field tile – it allows you to build it out without thinset squeezing through and makes them easier to prop up so they stay put as thinset cures.
Thank you so much for sharing your knowledge and experience. You explain things in a very clear and rational way. Web sites such as this are very rare…
Hi Roger,
I had my master bath remodeled about 7 years ago. We have a separate shower that we did all in tile and with a tile floor (typical shower pan under tile with liner). We now have a leak (not a large one, yet). The plumber tested the shower pan and the shower pan tested OK. However, the grout on the shower floor stays wet for a week or more in places (we are using the hall bath so as not to run water in the master shower and to test). Same thing with the grout on the sides and in the back of the shower where the water hits (wet grout up to about 4 ft.). My guess is water is getting behind and under tiles on both walls and floor and I picture in my mind a “mini-lake” underneath the floor tiles. What are your thoughts and solution?
Hey Mark,
Sounds like a couple of issues, I don’t think there’s a pre-slope under the pan – is that correct? You didn’t mention it, and while it isn’t the entire cause of the problem it certainly doesn’t help. I believe the main issue is that the weep holes in the drain are likely plugged up. Any water beneath the tile (completely normal) runs down the liner and into the weep holes. If they are plugged up it will simply continue to build – the mini-lake you mentioned – and will back up until it has nowhere else to go, that will likely be at the top of the liner where it can get to the framing or behind the waterproofing. The four-foot high wet grout you mentioned simply means the water has no place to drain.
You may be able to remove the tile around the drain and inspect the weep holes. If they are clogged up you can unplug them and reinstall your tile.
Thanks Roger. Not sure about the pre slope but I think there is one. However, only 3/4 inch slope from back wall to drain (about 3 feet) as measured by plumber when tested shower pan. If I remove tiles around drain and weep holes are not clogged was thinking I should go ahead and have entire base torn out plus one tile up on walls (14″ tiles) and have shower pan redone. Plus maybe remove grout to 4 feet up wall and re-grout. I recall a “traditional” method of construction was done on tile walls with either plastic or felt behind hardibacker. maybe important to note that I have wide grout lines (1/4″ to 1/2″ in many places) due to 14″ tiles and uneven edges. Does the above sound like a decent shot a permanent solution if it’s not just the weep holes being clogged? Thanks, love your site. Very professional AND entertaining. Bookmarked it and sent to others.
Yeah, if it isn’t the weep holes then there’s an open area in the liner somewhere. As long as it’s waterproofed correctly the grout line size doesn’t really matter, but it wouldn’t hurt to regrout after you dry everything out.
I’m going to try to only address the drain issue first (as you suggested). If looks like needs more then will redo the shower pan and re-grout shower. Do you recommend grout sealer for the shower or is it unnecessary? Is there such thing as a tile sealer or unnecessary? Will post what I find and ultimate solution when completed. Thanks for all.
Any tile sealer can be used as a grout sealer. Sealer is not necessary, it simply assists in cleaning. It DOES NOT assist in any way with waterproofing – in any manner at all. Really. I know it’s called ‘sealer’ – it shouldn’t be. If you have natural stone then yes, it should be sealed. If you have ceramic or porcelain then no, it doesn’t need to be sealed.
Hello–
So I’m not so sure about a “brilliant retort.” How about another question instead…
I too am renovating my shower and am running into some issues. My main concern is the durability and water resistance of the tile I purchased. The specifications say it is semi-vitreous porcelain tile. Now, everything I’ve come up with from the Google machine says it absorbs water. But after doing some searching, I’m relieved to find someone who obviously knows their stuff say, as I assumed, “For anything up to and including a regular shower, it isn’t necessarily an issue.” Specifically, I only intend to use these tiles on vertical surfaces. I have an experienced tile guy using concrete board, shower pan, and membrane to thoroughly seal everything behind the tile. The sills and curbs (any horizontal surfaces) will be marble, and he’s also applying epoxy floor. All that said, I want the tile itself to be as impervious as possible.
So, I guess my question is this: Would you put a semi-vitreous porcelain tile in your shower?
Also, these tiles don’t have matching trim pieces. What is the cleanest/best looking way too complete the transition between tile and drywall? At one point we have a column where tile and drywall will intersect at an outside corner.
Your straight talk and descriptiveness is refreshing. I’m looking forward to an honest, objective, and knowledgeable answer. (Especially because this is the tile my wife wanted, and I need to make it easier to convince her to return it for something better.)
Hey Williey,
Well, there’s two ways to look at this. A semi-vitreous tile absorbs 3%-7% moisture (by weight) so yes, you can get a more dense porcelain. A more dense porcelain is easier to clean (over the long run) and more durable.
However, provided your shower is built correctly it should be absolutely waterproof before a box of tile is opened – so it doesn’t matter how much water your tile will absorb. The epoxy on the floor (I’m assuming you mean grout) is not necessary in regards to waterproofing – your shower floor should be completely waterproof. So I really hope he’s not relying on the epoxy nor the limited absorption of the tile to assist with the waterproofing in any manner.
I’ve put semi-vitreous tile in many, many showers – most ceramic tile is in this absorption range, it works just fine. My personal shower, since you mentioned it, is marble and granite, marble absorbs about 4%-7%. Travertine, which I’ve also installed in a LOT of showers, runs into the 10% range with certain colors. The only place you really need to be concerned with the absorption range of a tile is if it is being installed in a steam shower (and even then it’s not a major deal) or being installed outdoors in a freeze/thaw environment where the absorbed moisture can freeze and expand inside the tile – the tile will crack. In a normal shower – not a big deal.
If this is a through-body porcelain (the back of it would be off-white) it can be bullnosed if your contractor knows how to do that. You can also get something like a pencil rail to finish off the edge with. Schluter trim profiles can also be used in lieu of a bullnose.
Thanks! That’s a relief.
We are getting real close to beginning to tile. If I decide to bullnose a very dark colored tile, is it going to look unusual? Is it common practice to have that exposed edge appear so contrasted to the rest of the field? I can’t recall seeing that.
Also (and sorry for veering off the original topic) I’m still weighing my options on what to use to cap a short wall on one side of the shower upon which I’m having a glass panel installed. I’m sure using a slab of stone would have the best look and function, but $ is an issue. Where would I even start looking to have some cut? What is the best quality? What is the best value?
BTW, I butchered my own name last time. It’s Willey (yeah it still sounds funny)
Hey Willey,
It is not very common to have a darker edge, but it’s your shower and a purely aesthetic thing. If you like it – do it.
You can go to a local granite slab supplier and they’ll usually have small left over pieces of stone which they can cut and finish for your wall cap. And you can usually get it pretty cheap since it’s left over anyway.
Stop butchering your own name – that’s my job.
Dear Roger:
Great forum – great advice and I’ve learned so much here today. My question concerns a wainscot in a bathroom with a tub/shower combo. The wainscot will be going up approximately 3 feet. Does this application need to be waterproofed on the walls where no water will touch it? What about around the sink area? Do you recommend backsplashes for the sink, as we didn’t buy them. We thought the wainscot around the walls would look nicer framing in the sink. Do I need the same waterproofing around the sink area that I do in the shower? We are back to studs right now, and getting the skylight installed at this point, so I have time. Thank you.
Hi Jane,
Any area outside your shower in the bathroom is considered a non-wet area (I know, technically it should be called a dry area, but I don’t write the rules
) Since they are not wet areas they do not require waterproofing. That said, it never hurts to waterproof any areas you think may see a lot of water, around sinks may be one, the wall right outside the tub all the way to the floor is definitely one.
Roger,
My son and I are doing a shower and we are using Noble TS for the floor pan on top of the required floor slop and the TS over Durarock on the walls. We are going to put 4X4 tumbled travertine on the floor, with sand grout, caulk at the floor to wall transition, and will seal with DuPont™ StoneTech® Professional Impregnator Pro® Sealer.
My son works for a home remodeling company and has done a lot of tile work, but this is the first time he has used travertine for a shower and we are getting a lot of different opinions of what order to do the job, seal tile before laying, lay tile then seal, lay tile grout then seal. We are of the opinion that we will lay the tile then grout and at the same time, we are grouting filling in all of the depressions and voids of the travertine with the grout, and last apply the sealer.
Your opinion and any other suggestions would be appreciated.
Hi Garry,
You guys are correct. If you want the depressions and pits in the face of the travertine filled you do not want to seal before grouting. The sealer will fill all the microscopic voids of the tile and not allow the grout to remain in the pits for very long. If you want the pits filled then the correct order is tile, grout, sealer. Great sealer choice and TS is good stuff too. Do make certain you follow the required grout curing time before sealing the tile.
Other suggestions? Well, my son should get a job… Oh, you probably meant about your tile. Soaking the travertine in a bucket of water and allowing it to dry before setting it will rid the tile of excess ‘dust’ created in the fabrication process and shipping/storage. Just toss ‘em into a bucket for ten minutes or so, pull them out and let them dry, then set them. This will increase your adhesion to the tile by about 20% or more and eliminate any bonding issues due to excess powder on the tile.
And my son still needs to get a job.
Have Fun!
Hey,
and then water gets behind the curtain and somehow undermines all that hard work. anyways i might be just paranoid but figured i would ask for your professional opinion. Thanks again for all the help, i could not have done this without this site! seriously… is there anyway i could send you some pictures???? mabey you could start a section of what your readers did…. or pick out my flaws and use it in the flawed… 
I wanted to say thanks again for all the help and information, i am all done and love the way the shower turned out but i have one thing left. I have gotten quotes for frameless glass but am having a hard time shelling out the $950 for it and was thinking of using a shower curtain instead. My question is, is the water retention of the glass setup worth the price or should the curtain do just fine?? my concern is that i dont put up the glass cause im a cheap
Hey Justin, Hallelujah! Someone finally finished a shower and told me about it.
You can use a shower curtain if you wanna. Your shower is waterproof under your tile, right?
As long as you properly installed your pan liner and it’s waterproof and the bottom of your shower curtain hangs inside the curb it won’t be a problem at all.
You can absolutely send me pictures. Just email them to Floorelf@Floorelf.com. I only have one other photo of a fireplace but I’ve been wanting to put up a page of everyone’s projects for a while. Maybe I’ll just do it and then people will start sending stuff, eh? Yeah – I do everything the hard way.