When you build a shower you will eventually need to make some holes in it – it’s just part of the overall process. You’ll need to install frames or hinges for your shower doors, grab bars, shower curtain rods, a picture of your pet iguana – whatever. The problem is that now you have that completely waterproof shower you really don’t want to go poking holes into the waterproofing.

No matter which waterproofing method you’ve used any fastener penetrations will have to punch a hole into it. You want to make sure you install your screws properly in order to maintain the integrity of the waterproofing. You don’t want to ruin all your hard work because you need to drive a screw through it!

The first thing you need to do is mark the exact locations of your screw holes. Most things like grab bars come with little templates you can hold up and get exact placement. With shower door frames and stuff like that you can hold up the frame piece and mark the correct location.

Ideally you want to have the placement of things like grab bars in mind before you even put the substrate up on the wall. This way you can instal backing for them. A 2×6 between the studs in the right location eliminates the need to use wall anchors and gives you a solid framing piece to screw directly into. That isn’t always possible (things are added later, layouts change, etc.) but if you can do it you will save a lot of time.

Spade drill bit for tileOnce you have the location of the holes marked you need to take your drill and put a hole there – all the way through the substrate. I normally use the spade-shaped bits for most tile and stone. They look like the little arrow bits and are normally labeled for use with glass tile, they work with nearly any tile. Make sure you get the correct size for either your screw, if you have backing, or your anchor if you don’t. They look like this:

You want to drill slowly! If you attempt to drill too quickly you may burn up the bit and/or crack the tile. That sucks – just trust me on that one. It’s usually easier if you have a spray bottle with water and mist it down as you drill through the tile, it helps keep the bit cooled down.

Holes drilled for screws It’s also much easier to drill through grout lines if you can. That doesn’t always lay out correctly, but it helps tremendously if you’re able to do it.

For this particular post I’ll be using a small two foot grab bar installed on a shower wall. You can click on any of the horrible photos to see a full-size version.

Once you get the holes drilled through in the correct location get some 100% silicone and fill each hole all the way up to the surface. This particular grab bar has a total of six screws – three on each end.

penetrations filled with siliconeOnce the holes are filled with silicone push your wall anchors all the way in. Silicone will ooze out as you do this, it should – it means you have a full hole and there is enough silicone to seal whatever you place in there.

The little red things are the screw anchors I’m using. If you have solid backing behind your screw locations you can just skip this step – you know – since you aren’t using screw anchors.

If you do have backing and aren’t using anchors you need to ensure that you have screws long enough to penetrate through the tile, through the substrate and into the blocking you placed back there. 2″ or 2 1/2″ screws are normally what you want.Screw anchors placed in holes

When you have your holes filled with silicone, and your wall anchors in if you’re using them, go ahead and install your grab bar or whatever is causing you to drill holes into your brand new tile.

As you drive the screw in the silicone will seal the penetration. No matter which waterproofing method you’ve used, the hole will be sealed all the way from the surface of the tile to the area behind the tile substrate.



Waterproof grab bar installed

And there you have it. Completely waterproof fastener penetrations in your brand new tile. As long as you fill those holes with silicone you will never have problems with leaking or any other issues that commonly derive from poking a hole in your waterproof wall.

Besides, if you’re hanging a picture of your pet iguana in your shower you already have bigger problems to deal with…

{ 118 comments… add one }

Leave a Comment

  • Nick

    After tiling shower on kerdi board I want to install a sliding shower bar in a new spot wher I did not place wood backing. Can I reliably use anchors in the tile and kerdi with no backing? Bar is not heavy but will have pressure from adjusting. Kerdi fix to bond anchors?

    • Roger

      Hi Nick,

      Yes you can. And you can use kerdi-fix to seal the anchor holes, but you don’t need it to bond them to anything. Just install them like you would in drywall.

  • Sean


    I’m working on installing a curb-less entry shower and want to know how to ensure that I get the glass panel installed correctly as well as ensuring that I have a proper capillary break installed at the shower door between the sloped shower floor and the main bath floor. My enclosure is 5′ deep and 7′ wide and will have a 28″ door with the balance being solid panel of glass from floor to ceiling & attached at one wall.

    I am using a Schluder Kerdi Linear drain at the back wall of the shower and will fully waterproof floor, walls, ceiling and bench with kerdi membrane.


    -1 How and where to install the capillary break between the shower floor and the main floor. What is considered a ‘proper’ capillary break?
    -2 Should I use a Schluder profile under the door, installed into the tile to help prevent water from splashing out from under the door?
    -3 Should the fixed glass panel have the channel screwed to the floor (on top of the finished kerdi) before the tile is laid on both sides up to the channel OR should the channel be screwed to the top of the finished tile down into the heavily reinforced, floor framing?

    Love the site, EXTREMELY, helpful!!!

    Thanks in advance!!!

    • Roger

      Hi Sean,

      1. A proper capillary break is just a material between the waterproof portion of the shower and the non-waterproofed portion of the bathroom floor. This is normally just silicone or sealant beading to create the ‘dam’. I normally install them directly outside of where the glass will sit. The way I do it is install the ditra for the bathroom floor, run the kerdi out over that about three inches and lay out the tile so I have a grout line right where the bathroom floor breaks into the shower floor. Install the tile up to that from the bathroom side and install a bead of sealant, ensuring it contacts the kerdi fully.

      2. It never hurts.

      3. That is an aesthetic question. Either way works fine. I prefer to have the glass as well as any channels installed on top of the tile. It’s just a cleaner look to me. Make sure the holes are drilled and filled with silicone before a screw is placed into it. This way it seals the penetration as it is driven in.

      • Sean

        Hi Roger,

        Thanks of for the detailed and quick response. I now have a complete understanding of what I need to do and plan for as I get closer to laying tile and performing the final sealing and capillary break between the shower and bathroom floor.

        Next question that just dawned on me… I’m installing a free-standing concrete tub in the main bathroom floor area. The whole floor will be kerdi & kerdi band around the perimeter of the room where ever practical. Under the kerdi, I’ll be using their ditra heat system.

        At the tub manufacturers recommendation, I’m using a OS&B island tub drain to make installing the tub easier and simpler since I don’t have access below the tub to make a final drain connection. I’m assuming that I should also do some sort of a similar capillary break of kerdi-fix or silicone under the tile, below the tub to prevent any water from migrating into that area as well…

        The OS&B connection is a neat idea but it essentially sits flush with the floor and is recessed down to accept the drain tail piece of the tub. So in essence, if some small amount of water migrated to that area, it could in theory collect in that depression as well as potentially find its way into other undesirable areas.

        1. Any words of wisdom or suggestions on other things that I should be thinking of as prepare for the tile installation under and around the tub?

        2. The tub is ‘hand made’ by Native Trails and in talking with the local rep, he says that it may not be perfectly flat on the bottom… any suggestions on how to best install/shim it so that it doesn’t crack the tile etc?

        Thanks again for your help and time!


        • Roger

          Hi Sean,
          A capillary break there wouldn’t hurt. However, I think you are WAY overcompensating for the amount of water your bathroom floor may have. You do not need to cover the entire floor with kerdi unless you are expecting a flood. Also, if you are going to cover the entire floor with kerdi there is no reason to have a capillary break between the main floor and the shower floor, since the main floor will be waterproof as well.

          Tile installation under and around the tub will be identical to the tile installation everywhere else.
          The tub manufacturer is the one you need to ask about the proper way to shim the tub. The only negative thing that may affect your tile is a point load, and that is dependent on whether or not your tub has feet, it doesn’t sound as if it does.

          • Sean

            Thanks Roger, again very helpful and insightful!

  • Nima

    I recently installed a corner shower caddy and had to drill two holes in the tile grout. I did not use any sealant, just the anchors and screws.
    Can I seal them now? How can I remove the anchors? Can I just unscrew, put silicone inside the existing anchor and then screw?

    • Roger

      Hi Nima,

      Yes, you can seal them by removing the screws, filling the holes (anchors) with silicone and reinstalling the screws. They will seal the hole as you screw them in.

  • Ann Berg

    Hi Roger,

    I was able to post the picture on your Facebook page, if you can take a look at it, and advise us, that would be great! You have been a great help over the years, at 5 tiling projects and counting. We did hire this last one out, at least the tile installation part, and that’s where our questions come in. We’re pretty easy to work for, but not certain what to do with this situation. Need advice! Thanks, Ann in Minnesota

  • Ann Berg

    last try on the picture. Basically, where the two tiles meet around the main shower controls, one tile is 1/8″ higher than the other at the very top. There isn’t any lippage at the bottom. I can ask the plumber if that’s going to be trouble, but by then we will have grouted it, and it will be an uglier job.

    Again, many thanks!!

  • Ann Berg

    OK, I realize I’m not a technology genius, here, but I can’t get that dang picture to post following the directions, so I’m going to give up for now : (

  • Ann Berg

    We are finishing up a travertine shower. Since we are both getting….old…..we decided to hire this job out, or at least most of it. We did the Kerdi shower and bench, but hired out the tiling. Our tiler had to cut our 18″ x 18″ large tiles into subway – type tiles (we paid him by the hour, so he was ok with doing that). Anyway, there was one tile (18″x18″) that had a large crack which had been epoxied by someone before we bought it. Looks sturdy, and all that, but it’s obviously a crack. Well, when the guy doing the tiling was working around the shower controls, he used that piece for 3 of the subway tiles, 2 of which ended up around the shower. Additionally, there’s at least an 1/8″ lippage around the main shower control (I attached a picture). I have two questions:
    1) How hard would it be to remove those tiles and replace them? There’s Kerdi underneath. Would other tiles fall off, or be damaged? If the cracks were in an inconspicuous place, we could live with it, but we’ll see those cracks every single time we use the shower. However, if it will damage the Kerdi/ other tiles, etc., we will just live with it, and not look at the shower controls. We have no intention of moving, so our kids will have to sell the house, and explain it to the new buyers : )
    2) Will the gasket for the shower controls fit over an 1/8″ lippage? We can grind that down a little bit, but not a huge amount, and it’s exactly the wrong place for a leak : ( (BTW, I, a 64 female person single-handedly installed the Kerdi in the shower, built a Kerdi bench, and installed the Kerdi on the shower floor, after buying your booklet on how to do a shower, so thank you!) We haven’t grouted the shower, yet, so that’s a plus if we need to pull the tiles and redo it. My husband or one of our sons can do the work, or we can ask the tiler to come back and pay him to do that.

    Normally, we do our own work, but this was such a big job, we hired it out. Mostly, it turned out good / great, even, and we’re really happy with it except for the shower and the cracked tiles that were used. Probably just as much as our fault, we could have / should have pulled that tile from the pile.

    • Ann Berg

      Thank you – the picture didn’t post for some reason, and I’m trying again to see if I can post it….. IMG_0598.jpg

    • Roger

      Hi Ann,

      It CAN be replaced with kerdi beneath it, but it really should not. There is always a risk of damaging the waterproofing. When I remove tile from kerdi I take a hammer and bust it into little pieces first, then gently pry off each little piece – less risk of damage.

      That likely happened there because the stud next to the controls always seems to stick out a bit further than the others, that framing needs to be shimmed flat before the substrate is installed. The gasket MAY fit over that lippage, but I wouldn’t put money on it.

      If you decide to replace them and do damage the kerdi you can always patch it (which will create more unevenness) or get something like redgard and paint it over the damaged areas.

  • Rommel Sison

    Does using silicone in drilled holes on concrete roof deck seals the holes from water?

    • Roger

      Hi Rommel,

      It will temporarily, but silicone is not a wear surface, so unless it is covered with something to prevent abrasion on the silicone (like tile) it will eventually fail.

  • Mike

    When my tile installer anchored the grab bars he did not use any kind of waterproofing to prevent penetration of water via the screws. Can I remove the screws and fill holes with silicone and not compromise the stability of the grab bar?

    • Roger

      Hi Mike,

      You should be able to. It depends on the type of anchors used and whether or not they will fall back into the wall cavity once the screw is removed.

  • Mitch Stockton

    Hello Roger!!!

    I was unable to attach photos (jpg too large – 1MB limit seems very small and I’m not very computer literate). Anyway,

    Water is somehow escaping my shower stall out onto the carpet. This only seems to be happening in one corner (please see pictures).
    I carefully removed and replaced the clear silicone around the leaking area (enclosure) but the carpet is still getting wet in that one corner. I then placed a folded piece of tissue paper on the outside corner ledge of the pan (tissue was also in contact with exterior shower tile and grout) and another piece just below it but on top of the carpet. I then took a shower. Shortly after my shower I checked both tissues and they were dry. I checked them again a couple hours later and they were WET???

    Any help would be GREATLY appreciated.

    Mitch in northern Nevada

  • Colleen

    Neither your tile design book nor the blog, apparently, covers my penetrating question.

    My tub enclosure has a glass block window in the sidewall opposite the showerhead. It’s between the living area and the shower, not the outdoors, but never mind that. This is in a new construction so the enclosure walls are still just bare framing.

    The window is slightly thinner than the thickness of the wall. When the builder (my brother) and the unskilled labor/contractor (me) installed the window in the wall, the unskilled labor neglected to pay attention to which side of the window was being placed flush with its wall. So it ended up being flush with the living area drywall, and it’s inset on the tub enclosure side, 11/16 before the cement board is even installed. Make sense?

    So now I’m scratching my head over how I’m going to tile around this window and make it waterproof.

    I do plan to install a 90 degree shower curtain rod so that the curtain will go across the back of the tub and then the front, because I figure houseguests might be shy about showering in front of a window, no matter how blurry the view through it. Still, you can’t depend on houseguests to keep your glass block window from getting wet.

    Are my chickens going to spontaneously combust now?

    • Colleen

      Hm, the pictures didn’t upload the first time around.

  • John

    So, I found the structural issue simple. There is the steel I beam right about where I was going to shore up. I oubled up the joists and added blocking over the beam between joists. Around perimeter as well to reattach plywood. The offset drain (in corner) out maybe 6-8″ from walls could be moved to center of 3.5″ wall but not toward center of long side due to structure. Will it look funny to have that much slope to the drain near the corner?

    • Roger

      Hi John,

      Yes it will. That’s why I opt for the unlevel perimeter, with the bottom row of tiles cut to follow it.

      • John

        Thanks Roger. Unlevel bottom row sounds like best option. A little less cement too.

  • John

    I hve a question on offset drains. I bought your book but it does not say how to handle offset pan drains. I removed a 3 X 3 fiberglass corner shower. For it I plumbed a corner drain. I could relocate the drain if needed but if I leave it in the corner of the traditionally sealed 3.5 X 4.5 corner shower I am building do I:

    Leave the drain and have that corner at 3/4″?
    Taper rest out to farthest point like example with center drain in book?
    This is on a wood floor with 2 X 6 joists on 16″ centers. It is a mobile home so access under floor. Should I double up the joists and shore up joists by adding a header under on either pier blocks or adjustable mobile home stands?
    I replaced the particle board subfloor with 3/4″ CDX last time around with fiberglass shower.

    • Roger

      Hi John,

      You can do one of two things if you want to leave the drain where it is. You can measure 1/4″ per foot to the furthest corner, make the entire perimeter that height just like a centered drain, and you’ll have a steeper slope right around the drain. Or you can run the perimeter from the height of the drain to 1/4″ per foot all the way along the walls, which means you’ll have a non-level perimeter so you’re bottom row won’t all be the same size.

  • Brian DeBill

    Sir, I was in the middle of removing grout from my shower because of many cracks in the old grout that tricked outside of shower and into the wall. Any how, when removing it with a dremal multi-tool I penetrated through the hardi and through the wall. My question is, Do I have to remove the tiles now and replace the hardi or can I must go ahead and grout it or what should I do?


    • Roger

      Hi Brian,

      It depends, is your shower waterproofed? (hardi is not waterproof) If so, what type of waterproofing do you have and was it penetrated while you were using your dremel as a long-sword and fighting ogres with it…

  • Kevin

    Hi Roger-
    Great site, thanks for all the great tips. One question I haven’t found answered.. I pulled up linoleum from a basement concrete (bathroom) floor. Tub & shower surround are done; for the floor, what is proper preparation? I’ve removed damn near all the gunk from the linoleum; cleaned with TSP.. do I need to coat with Redguard waterproofer, or…?

    • Roger

      Hi Kevin,

      Splash some water on the concrete, if it soaks into it within ten seconds or so you’re fine to go over it with thinset. If it beads up and sits on top you need to cover it with something to which thinset will bond – redgard will work just fine. I always prefer to use a membrane such as ditra over the concrete, then tile on that.

  • Joe

    Thanks for the nice tutorial. I am installing a handle shower bar in a Schluter shower and have a stud to attach to.

    I am using a hole saw diamond coated bit to drill thru the tile. Should I stop when I reach the drywall? The wood screw can cut thru the rest but is that deep enough to fill the silicone and have a water tight seal?

    • Roger

      Hi Joe,

      Yes it is deep enough.

  • Tom

    Hi Roger,
    Once again your site popped up on the Google with the info I needed. ..and more….

    For the pet iguana pic, should I go with 11×14,or try and find one of those custom print houses that could wrap the entire shower with a pic of my iguana? Maybe graphic wrap could be waterproof too! It could be the new thing, thanks for the idea!

  • Rick

    Hello Roger,

    I am planning on installing a fold-down seat on the wall opposite the ‘wet’ wall (where the shower fixtures are located). This fold-down seat was in the plans from the beginning of this shower project so I reinforced the wall area with two 2x4s going horizontally between the studs. The seat is made for showers. I have 1/2 inch hardibaker substrate and then 12×12 wall tiles. The brackets for the seats (left and right sides) take 4 screws each. Three screws in the top of each bracket that span a total distance of 3 inches and one screw in the bottom of each bracket approximately 3 inches below the center screw in each bracket. It is a fold down seat with no supporting legs. It is only supported by the brackets. My question is – when I install this seat, is there a potential for the brackets and screws to place too much force (torsion) to the tile on the wall and possibly pull the tile away from the wall or possibly crack the tile?

    Thanks for your help.


    • Roger

      Hi Rick,

      Provided you hit the studs you placed into the wall, and they are fastened securely, it shouldn’t have any problems at all.

  • Charles

    Hello Roger,

    For a tub surround redo, what do technique/products do you recommend to clean up the bathtub surface (remove old caulk and dirt) before installing hardibacker and caulking it to the tub? I am going to put Hydroban on the hardibacker. I was thinking of using a razor blade for the caulk and a Scotchbrite pad with Simple Green for the rest. Does the surface have to be perfectly clean, or is it ok to have some tiny rough spots here and there?

    Also, I installed hardibacker on two short walls which are at 90 degrees and will be subway tiled (the cooking range goes against these walls). Before I found your site, all joints were taped with thinset, including the corner and Redguard was painted on the seams (with mesh in the corner seam).

    The wall will have subway tile. To follow your recommendation to not thinset vertical corners,I was thinking of making a cut down the corner, running a caulk bead, and then reapplying Redguard with mesh to allow for independent movement. Is it worth the effort for a “range surround”? The only water the wall would get would be a spill or maybe steam from cooking.

    Thank you.


    • Roger

      Hi Charles,

      Razor blade and scotchbrite will work fine. A few rough spots are no big deal. I would leave the corner as it is, it’ll be fine with a range surround.

  • Karin


    Just checking that this is the waterproofing concept I would use when installing a slide bar over the Schulter-KERDI membrane?



    • Roger

      Hi Karin,

      Yes it is.

  • Randy

    Super site/info! I wondered about penetrations messing with the nice waterproofing- good read. Q: I will be making my shower curb out of concrete/brick blocks as mine is on top of basement concrete floor…this site convinced me of this verus wood 2x4s. So…..when I install my shower door on top of my concrete curb….how do I screw/fasten the door fasteners into/onto the curb??? I will be using 2 layers of approx 2″ brick plus thin layer of thinset over this so I can stick the kerdi membrane over it then tile over the curb. Now when the shower door instructions call for screwing a few door brackets into the curb (sliding door) what do I use (tapcon screws?? Do I predrill the screws using masonry bit first?). Do I need a 2×4 on top to hold the screws or is solid concrete and tile the way to go…..I only want about a 4.5-5 ” curb height and I intend on backsloping the curb by 3/8″ for drainage when I tile it… help appreciated!!!!!

    • Roger

      Hi Randy,

      Never saw a shower door call for that. Normally the bottom rail is siliconed to the tile and the two side rails are set on top of the ends to hold it in place. Are you sure that’s what it calls for (you already have the doors)? Or is it just assuming it’s attached in that manner?

      You can use tapcons by drilling, filling with silicone, then installing if that’s what you need to do, but I highly recommend against drilling into a curb for ANY reason.

  • Larry


    wanted to ask a quick question. But first a history, this is my second tile job, the first was the downstairs half bath, turned into full bath with steam/shower, learned a lot, pony walls, neo-angle, etc. which included all kinds of life learning experiences after being ripped off by the (so called) contractor, if I had only used the baseball bat on his ass! Anywho, I am doing the second floor hall bath, removed iron tub, installed whirlpool tub, reduced the size to add to the extremely small master bath. At the moment I am doing the tile, this is when I found your site because of niches, (just so you I had done some things wrong and some a lot better then the steam/shower). Now to the question, I had to remove a couple of tile after they had been in place for a day, due to miscalculating measurements (spacers). In do so, I damaged the Redgard. What is your recommendation in repairing? I was going to use fibertape and mortar, allow to dry then reapply the Redgard in the damaged area. So in stead of jacking it up, thought I ask you.


    • Roger

      Hi Larry,

      That’s exactly the correct way to repair it.

  • Ramon

    I am doing a job that as of now will be two bathroom floors over well aged concrete. The homeowner wants heating mats and the new Ditra system is about 3x any other mat so I am using “another” but still want to use Ditra under the tile…I know that the heat mat must be encapsulated..Under or over the Ditra? Please suggest a BRAND name thinset suitable to 1.)Encapsulate the heat mat. 2.) bond the Ditra to the concrete and 3.) Bond the tile to the Ditra. I am very confused about the thinset requirements. Thanks so much..Ramon

    • Roger

      Hi Ramon,

      You need unmodified thinset for everything in that installation. If you read through my post on unmodified thinsets it will give you the rundown of all the most commonly available.

  • Ann

    Dear Roger,

    We are doing our umpteenth tile installation. Or, at least it seems that way. Our oldest son was over last night, and, as usual, was giving advice to us on what we are doing WRONG on our tile installation plans. Since there is at least a small chance he is correct, I thought I’d ask your opinion.

    We are planning to put 21″ x 21″ tiles in our basement bathroom floor. They are very high quality, textured-type commercial tiles. He stated that tiles installed on concrete will always, always crack, and that we should go with smaller tiles to prevent this. (He worked at one time for a “high-end” remodeler, so he has some experience in these matters.)

    Our first thought is that if the tiles are installed correctly, with actual thin-set under the entire tile, it shouldn’t crack. But, what do we know? We’re just the old, feeble-minded parents. Should we play it safe and put Ditra over the concrete and under the tile? Go with smaller tiles? Give up and use carpeting?

    We couldn’t have done the tile projects we’ve already finished without you….many thanks! We have already purchased your Design, Tile Tips, and Shower/Tubs manual, and are rereading them several times before proceeding with the basement bathroom remodel – then we’ll tackle the upstairs with the Kerdi shower kit, so we’ll order that book at that time. You have done everyone a favor by writing all this stuff down!

    • Roger

      Hi Ann,

      He is partially correct. Concrete ALWAYS cracks – always. If tile is bonded directly to the concrete it will crack as well, in the same spot. It does the same with smaller tiles, except it will normally only give out at the grout line, since it is the weak point and there are a hell of a lot more of them. A crack isolation membrane of some sort is best, be it ditra, redgard or whatever.

      Concrete also is manufactured to crack in specific areas, the expansion or saw joints. You need soft joints over these, whether the membrane is there or not. This compensates for the controlled crack.

      • Colleen

        Concrete always cracks? In a new construction, my bathroom floor is 5′ x 8′ slab on grade. Surrounding floors will be adobe so this is like a standalone pad. So I shouldn’t tile the bathroom floor directly on the concrete? Better to find out now rather than later!

        Same goes for the cement pad under my woodstove, which is only 30″ x 50″. It will crack?

  • Freeman


    I am in the process of installing the backerboard surround for my new shower and am going with the liquid redgard method for waterproofing but am stumped with one issue. The water fixture has a 3″x5″ plastic plaster guard that is supposed to be installed flush with the interior finished wall. The plaster guard has a number of holes for the attaching screws and water flow adjusting screws. My question is how do you seal this type of penetration? I realize that the escutcheon has a rubber seal that will surround the opening but water will still be able to follow the grout lines and penetrate the opening.

    • Roger

      Hi Freeman,

      The water running down the grout lines is stopped by the foam on the back of the escutcheon. For the rest of the waterproofing of that hole, you do it like this.