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

  • Carli

    my shower door is leaking out puddles of water. The bottom ledge that meats with the glass door is slightly angled down, so when the water hits it it runs out the grout lines, down onto the floor and makes a pool of water. Would a new Bottom seal with A drip rail do anything to fix my problem? Any suggestions??

    • Roger

      Hi Carli,

      It sounds like your shower curb is angled the wrong way. It needs to be sloped into the shower, not out of it. A drip rail and seal will not stop that since it can’t really completely seal a grout line, which dips. The only true solution is to remove the top of the curb, build it up on the outside so it angles into the shower rather than out of it, and retile it.

  • Linda

    I am having a shower tiled by a contractor. When I asked him what he was going to use to waterproof the wonderboard he said he did not have to tape the seams and he did not use any waterproofing. He is going to put the tile right on the wonderboard with mastic and grout. He has done the ceiling and the back wall and I have stopped him from doing any more. Not sure what to do now? Do I have to remove what he has done and start all over?

    • Roger

      Hi Linda,

      1. Fire his ass
      2. Remove what he’s installed
      3. waterproof your shower
      4. install tile.

      Or, do #1 yourself and hire someone who knows what they’re doing to do the rest. :D

  • Yakov

    Hi Roger,
    I am going to install Kohler sliding shower door.
    I have porcelain tile on the wall.
    I did drill 5/16″ holes in the wall and 7/8″ deep for wall jambs, also my anchors are approximately 7/8″ long.
    I think I did something not right. Went on You tube and check how to install Kohler sliding door and saw that they use that diameter drill and anchor for plastic walls not porcelain.
    should I install this anchors and use 1 1/2″ screws how manufacture recommend or change screws to size 2″ – 2 1/2″.
    I just worry that I should not use this anchors.
    Should I also drill holes dipper but use 1/16″ drill beat to make easy longer screws go in.
    Of course I will fill the holes with silicone.

    • Roger

      Hey Yakov,

      I would just leave those holes and use larger screws. If you have solid backing behind the rails just do away with the anchors, you can use them with longer screws if you need to, though.

  • Jim

    Mr. Elf – why 1/2 instead of 1/4 inch backerboard on tub surrounds?

    • Roger

      Hi Jim,

      1. Because 1/4″ backer has too much deflection between 16″ oc studs
      2. Most drywall on the outside of the shower, where your backer will likely butt to, is 1/2″.

  • gary

    Hi Roger,

    I am looking at installing a frameless 3/8″ glass door. My opening is 34.5″ wide plus or minus 1/8″. The brand I was loking at has a 28″ door with a 6″ stationary panel. So the panel has a clip that attaches to the curb. Should I avoid this and try to find a hinge only 34.5″ door sans panel or is the curb penetration OK? Thanks!

    • Roger

      Hi Gary,

      It’s better NOT to penetrate the curb. But if you must drill the hole, FILL it with silicone, then install the fastener.

  • gary

    Hi Roger,

    I was going to use plumber’s putty for the holes for my tub spout and shower arm, is that ok?

    Also how do I deal with the punctures in the vapor barrier for these water sources, should I use the siilycone :lol2: ?


    • Roger

      Hi Gary,

      Silicone would be better than plumber’s putty, which will dry out over time.

      Waterproofing fixture penetrations

      • gary


        I am having a hard time finding a frameless glass door that is 34-35″ wide…a coupla more questions, and many thanks for answering all of my rookie questions…

        1. Should I worry about penetrations of my vapor barrier by the screws from the ledger board – I heard that applying Kerdi products or sillycone to the scrwew hole in the hardiebacker is often done BUT what about the hole in the vapor barrier – can condensate leak out these small punctures in the vapor barrier? I guess the same goes for all of the punctures caused by staples and hardiebacker screws as well. My inclination is to fill the ledger holes with thinset and forget about it.

        2. Should I create drain holes in my caulk at the bottom to alllow drainage of water? If I don’t do drain holes and if water sits on the caulk how will that issue manifest itself?

        • Roger

          1. When you put silicone in there it will seal the holes in the barrier as well. Penetrations with the fastener left in seal around the fastener and don’t allow water into them.

          2. Weep holes

  • L (LANELL)

    I am sorry forgot to answer about the call I made long ago that had a rep assuring me Silicone was good to use to stick TILE to durock…. I know the place you are referring to IF a 502 area code. No… Was THE silicone site itself. Someone had too much adult beverage that day and was trying to sell me a 5gal. bucket of the stuff.
    I am still held up waiting on glass estimate (window and door) bu8090t have enough Durock dust to prove progress. And I will do my own window and door when time comes very soon.

  • LaNell

    Hi Roger… New day so new question from lady DIY’er. As for tile over Duroc, an Indiana company I spoke with assured me porcelain tiles would easily and ‘waterproofly’ adhere forevermore with 100% silicone adhesive/sealant. This is a fumey, messy product I have used for decades. I even know how to easily clean it from my skin.
    Questioning if you would trust it on all counts in shower walls and pan? Over Red Gard or AQUABAN coated Duroc?
    My project awaits your input.
    I am in SW FL so temp varies rarely from 65-95 For.

    • Roger

      Hi LaNell,

      Absolutely not! That is not even close to a proper method and won’t last long-term. If I were you I would lose their phone number. :D The company didn’t have the name of the state followed by the word floors, did it? You need to use thinset. It is the only proper product for your installation.

  • Greg

    Hi Roger,

    I recently finished my first Kerdi shower install. The Kerdi is installed on drywall and 16×16 travertine is installed on the walls of the shower. I used the foam shower pan and curb, the shower floor has 4×4 travertine installed on it. It was a definately a learning experience but I am very proud of the result. We have been using the shower for approximately 2 months and I couldn’t be happier with it. Unfortuneatly that came to a screeching halt yesterday. The grout line, where the tiles on the top of the half wall meet the vertical tile surfaces of the shower wall, is cracking. The cracks are on both sides of the half wall and extend from between each of the glass clips/clamps to a few inches past each clamp. I suspect that the glass installers drilled through the top of the wall (piercing the Kerdi) to install screws for the glass clamps and then neglected to seal the screw holes with silicon or some other sealant. The piece of drywall under the tiles is probably wicking up the water (throught the screw holes) and has expanded enought to displace the tile upward.

    My two most burning questions are:

    Is it common practice for the glass installer to seal screw holes when installing hardware in a shower? I would think that even in a shower that didn’t use the Kerdi method you would still seal any holes to prevent water from intruding.

    What is the best way to fix this? If I need to remove the wet drywall how do I remove the travertine tiles with destroying as little as possible in the proccess? Should I just break out the two tiles, slit open the Kerdi and remove the we drywall?

    • Roger

      Hi Greg,

      I don’t know how common it is, but good glass guys ALWAYS seal the penetrations before driving the fastener into it. Removing the tile will damage the kerdi, there is no way around it. The best thing to do it remove the grout around the tiles you’ll be removing and cut all the way around them, through the drywall, before removing them. Then remove the tile, kerdi and drywall all at once. It is the best way to do it with the least damage. If you try to just remove the tiles you’ll rip the kerdi off the wall and it may damage kerdi under tiles you want to leave.

  • Devin

    Thank you for your help with everything. I have looked around, but have not found anything, so I apologize if this is a repeat question.

    Thoughts or concerns with RedGard over HardieBacker 500? I did not think this was an issue, but I have been reading a lot of people have adhesion issues; pealing off from the backer board, not sticking, etc. Any tips or advice?

    I have already applied my first coat last night, I will check how well it has adhered tonight.

    Also, what about tiling over the RedGard with a trowel? Doesn’t a notched trowel cut through or scrape off the RedGard, essentially making it ineffective?

    Thanks for the help.

    • Roger

      Hi Devin,

      I normally do a prime coat first with 1 part redgard and 3 parts water. That gets it into all the open pores in the backer. Normally it’s not really a problem, though, provided you had a clean surface on your hardi. Keep in mind as you are peeling the redgard (or trying to) that the tile will NEVER put that specific type of pressure on the redgard. If you can grab one end of it and slide it off the hardi I’d be worried, but you won’t be able to do that. :D The trowel isn’t going to damage the redgard.

      • Devin

        You are awesome, that’s all I really have to say about that.

  • Sandi

    Well it gets better!!!! Just found out Home Depot recommended and sold us AcrylPro by Custom to tape finish all seams on Hardie board. It is not a modified thin set which they should have known. Contacted Custom and they say to use a paint /adhesive stripper to remove their product. Contacted Hardie and they say that will damage their board!!!! Met with HD and they have accepted responsibility and will give us new materials!!! Stupid idiots!!!!! Since we are now paranoid we had a builder come over. He says ” neutralize” the problem by going over the existing materials with the correct tape and VersaBond thin set covering all seams and everything will be fine!!!!!! Have you EVER with all your communications heard of this happening before and resolutions or resources to check with?????? We just want to do what is correct and no problems in the future and no cracks ,problems showing on our finished shower down the road!!!

    • Roger

      Skimming over it with thinset is a band-aid, at best. The correct way to do it is to remove everything and begin again. Anything else is really just trying to cover up an incorrect base.

  • Sandi

    I taped with the mesh tape and skimed corners per Hardie instructions. After trying overnight one corner has a crack line (separation )going about 12 in down middle of -area????? What is going on or what do I do, just skim again????

    • Roger

      Hi Sandi,

      Yes, just skim it again. It’s fairly normal, thinset shrinks as it cures.

  • Sandi

    I have installed a new shower mud pan and all Hardie boards. Please tell me EVERYWHERE I need to apply silicone caulk before I do tile installation??? Example, so I caulk where the pan and board meet before tile?
    Love this site

    • Roger

      Hi Sandi,

      In the corners from floor to ceiling. Then tape and mud all corners and seams in the backer.

  • Steve


    1. My understanding is that glass installers tend to want to drill holes in the curb, but that the curb is particularly vulnerable to water leaks. What is your position on drilling holes in the curb? Avoid it? Seal it with silicone as described for grab bars etc…? (I’m using kerdi over hardie if that matters)

    2. Do you have any experience / thoughts on using a local supplier / installer for glass enclosures vs ordering “custom” glass from an online shop (or locally, I guess) and installing it myself?

    3. Do you have any recommendations for glass suppliers/installers in Denver?



    • Roger

      Hi Steve,

      1. Don’t let them. It’s not required unless the door is hinged off the curb. If they say they will, find another glass guy.
      2. I’ve never ordered them nor installed them, so I don’t know. I’m one that let’s the professionals do they’re job. Especially with something that’s gonna cost hundreds of dollars if your hand slips once. :D
      3. Don’t know about Denver, I’ve had the same guy here for about 12 years.

  • Carl

    I have read your “book” on installing Kerdi membrane and I have questions.
    I’m building a shower using a Swanstone shower base. Their instructions (http://www.theswancorp.com/images/link_installation/Form%20200%20-%20Shower%20Floors.pdf) are vague when it comes to using tile with their base. The vertical part of the base lip sticks up about 1″. I assume (dangerous) that the substrate, 1/2″ hardibacker, will come down to within 1/4″ of the top of this flange. (They recommend 1/2″) Can it be less than 1/4″ Should it be more than 1/4″?
    Next, as I interpret your instructions, I attach the membrane, using thinset down to the bottom edge of the substrate, and leave the membrane extend to the horizontal surface of the shower base. I then “glue” the back of the membrane to the vertical face of the shower base flange using silicone caulk. The face of the substrate may or may not be flush with the base lip. The base lip may be recessed slightly by as much as 1/4″. If I then tile down to the horizontal face of the base, I think there may be some voids behind the tile near the base (In that last inch or so). Is this a concern? Should this void be filled in flush with the face of the substrate before tiling? And if so, using what?
    Any suggestions or comments are appreciated.

    • Roger

      Hi Carl,

      Yes, it is normal and no, it isn’t a concern. You don’t want to fill that with anything due to differential movement between the base material and the tile, they will expand and contract at different rates. Trying to fill it with anything will likely lead to problems.

    • nancy walker

      roger, hey-hi. I am doing this exact same install. However I could not get my Kerdi to embed the thinset because I am not fast enough to work a large area. I have accomplished a 6” wide band around the bottom to meet the Swanstone base, but I am thinking Hydroban would be easier for me to use to waterproof. Since my whole left wall is now covered with unmodified thinset over the hardie will it be a problem for the Hydroban since I have read to use latex thinset under it.? I am going to have beer while I await your wisdom. ;)


      • Roger

        Hi Nancy,

        I hope you scraped off the thinset. Yes, you can go over it with hydroban with no problem. If you still have dried ridges of thinset, though, they need to be scraped off first. I know you probably don’t, but if I don’t say it… :D

  • Pamela

    We have a tile ready shower pan in a new shower what is the best way to install tiles shower pan tiles first then wall tiles so they rest on floor or does it really make any difference since we don’t plan on doing complete job same day we can do it either way we just want to do it right if it makes any difference thanks

    • Roger

      Hi Pamela,

      It doesn’t really make any difference. I prefer the floor tile under the wall tile, it just looks better to me.

  • Shannon

    I’m back with another question, we’re getting ready to tile in the shower (walls and floors). I’ve been reading about using a ledger board for the wall tiles, but I’m hesitant to screw through the regard membrane. I know we could just put more regard on afterward, but I think I just need you to tell me that it’s ok or that it’s not ok and there’s a better way to attach a ledger board.


    • Roger

      Hi Shannon,

      Yes, it’s just fine. You can also put them up with double-sided foam tape, but that will sometimes pull the redgard off when you remove it, so the screws are better anyway. You can also prop the ledger board up from beneath if you want to.

  • Mark

    What about the option of using some form of Epoxy resin based adhesive?
    I realize it would not form a strong enough bond on a handle for some fat ass yank to haul their 200+Lbs upright on a daily basis, (do such fat slobs shower daily? They never smell like they do!) but if I just want to fix a small corner stainless steel shelf into the corner of my shower to put my shower gel and shampoo on would it not work, and it does not penetrate the tiles/waterproofing at all?

    Could one not attach the handle to the wall before tiling?
    Then paint the walls with the water-proof red stuff that is visible from space? Use fiber-glass-matting as needed and the handle is fixed, and water proofed before the tiles go over it.

    If the person is heavy enough to break the seals one way they are heavy enough to break it regardless.

    Forgive me if I fail to understand, but I am in the UK- my flat is bricks & concrete blocks, not wood and plaster-board. I can not make a “shower nook” by cutting a 4″ deep hole in the wall on the back of my shower, a 4″ cut out in the back of my shower would go right through the wall, an let me see next door watching TV. :corn:

    • Roger

      Hey Mark,

      I guess it depends on what type of tv programming your neighbor watches. :D

      Yes, you can use epoxy to attach corner shelves. Provided they are not used as a step ladder it will stay put and the epoxy will waterproof it.

  • Jon

    I have installed 1/2 inch Hardie backer board in a shower area from tub to ceiling. I then used 3×6 subway tile, 8 rows off the tub and then 7 rows of clear penny tile. I did not seal the backer board before installing the tile. On the 5 foot back wall of the shower, on the corner next to the water supply I am getting brown staining in the glass tile about 18 inches from the corner. I have torn out this section one time to get rid of the staining and the backer board was totally dry. For a few days was fine but is now brown stained again. Is it possible something is bleeding though the backer board? Should I cut that section and apply new backer board? I need to remedy the situation that there is no longer any brown stain. What do you advise?

    • Roger

      Hi Jon,

      Is the staining on the face of the tile or behind it. How was the penny tile put together? A mesh behind it or a paper coating over the face? If the staining is behind the tile is it also on the backer or just on the tile?

  • Denise

    Hi Roger,

    Love the site and how you explain things.

    Could you please not tell people that it’s OK to install grab bars with screw anchors? They really do need better backing…studs or installed backing. These are good if you can’t hit a stud – http://www.toggler.com/products/snaptoggle/tech_specs.php . Only a 1/2″ hole. No, don’t work for the snap toggle people.


    • Roger

      Hi Denise,

      I would love to if the manufacturers of said grab bars agreed with that line of thinking. However, when a grab bar is packaged with those same screw anchors it’s difficult to tell people that the manufacturer of the product is incorrect and I know better. Also, when I install one of those with the six supplied screws and anchors and can stand my 210lb. ass on it I find it difficult to tell people that they are insufficient for said use.

      Larger, more secure anchors are better, solid backing is always best.

  • Bubba N.

    Great site man! My wife and I used this as a guide through an entire D.I.Y. bathroom/custom pimp shower remodel even including two beer holders!!! We are almost done!

    Thanks for putting in the time to help others out! It has been really appreciated.

    B + V :rockon:

    • Roger

      Sweet! New byline – PIMP MY SHOWER! :D

  • Svend

    Hi Roger,
    I’m glad that I found your web site today, have been reading for a couple of hours now. Great Site, thanks. I have downloaded your free manual and I’m trying to decide which system to use on my project, a finishing of a shower that was roughed in when the house was built, but the room was used for document storage for quite awhile. Shower will be 32″ x 48″ finished size and two wall is currently 5/8″ painted drywall. My question is, if I choose to go with a Topical system and use a liquid application on the wall, will it be OK to just apply 1/4″ backer over the drywall or should I get down to the studs. When I was searching for more information on the systems I found that Redgard now has a fabric system similar to the Schluter. Thanks for your help.


    • Roger

      Hi Svend,

      If you want to use a liquid topical membrane you need to remove the drywall and replace it with cement backerboard. Kerdi can be used over the drywall (although you’ll need to rough up or remove the paint), liquids can’t. Redgard has come out with a sheet membrane but I honestly don’t know a thing about it yet, so I don’t know if it is approved for use over drywall yet.

      • Svend

        Hi Roger,
        I purchased your manual on the liquid topical membrane and on page 11 you have a warning saying “Never use pressure treated lumber…Ever!!!” but you don’t state your reasoning for that warning. My house, like most here in the California Desert, is built on concrete slabs with pressure treated base plates, so the three walls surrounding the shower stall will have pressure treated lumber against the concrete, so why can’t it be used as the base for the curb. If it is the connection to the concrete that’s a problem I can shoot it in every 12 inches, use KD lumber for the rest and wrap it all with Hardiboard. Just wondering. :roll:

        • Roger

          Hi Svend,

          The problem with using it for the curb is that you’re covering it completely, sealing it from all outside influence save for the concrete. This means that absolutely no vapor can dissipate. Since it’s on concrete, and pressure treated, the wood will attempt to stabilize the pressure from the internal moisture and the concrete. This is why it works for baseplates. So it will either absorb moisture until stabilized or release pressure until stabilized. The first leads to expansion and the second leads to contraction. To do this there must be a place for excess vapor to dissipate – it will do this into a wall cavity. It can not do this if sealed in a curb with tile installed over it on three sides. When it expands or contracts it will warp and crack grout and/or tile.

          • Svend

            Thanks Roger,

            That makes sense!!! :-D

  • Zack


    Hell of a site man. I’ve not a clue how you can keep up with all of this. I’ve read quite a bit of it, don’t know how I have time either- probably should be grouting somewhere. Most of what you said I’m spot on with you. One thing though, about kerdi and hardibacker. I prime the hardi so that I can get the sheets on in one shot. Thought myself pretty clever when I came up with it, but now you’ve got me second guessing myself. I agree that it would seal the pours as you said but I’m having trouble seeing any difference between that and the paint-on waterproofers (maybe a word). What do you think? This will keep me up at night. I’ve got contemporaries that I wouldn’t let tile my dog house, no prepan, burnishing (flat trowelling) etc. so the thought that I am hacking something doesn’t settle.

    • Roger

      Hey Zack,

      Nope, you’re fine. Priming it helps. Sealing (what I’ve mentioned to a couple of different people) means not with any type of concrete sealer. (yes, people ask me that) If you’re using killz or a specific primer made by TEC or someone then it will definitely help, that actually creates more surface for a bond (it creates peaks and valleys on a microscopic level).

      I don’t know how I have time for it either…beer? :D

      • Zack


        Thanks. I should of thought of that.

        May all your tiles be full and your concrete flat.


  • Mark Chavez

    My question is: when tilling a shower do you have to make grout lines or can I lay the tile right next to eachother?

  • Jim

    The Kerdi membrane is up and the tiles are ready to go on. My project is headed toward total success because of what I’ve learned from the Floor Elf. I’ll have a few holes to drill for the glass enclosure/shower door, but now I know how to do it!