Another request from one of my readers, this time concerning weep holes. As you may know I answer every question I’m asked here on my site when I sober up get home from work. I have tried to explain in the comments section several times where to create weep holes in a tub or shower (acrylic base) tile installation and now realize it’s a difficult thing to do with words.

So when Kurt asked me to clarify exactly where they go a stroke of genius hit me! (Yeah, I’m slow sometimes) I have pictures. Well, not exactly pictures of the weep holes themselves, but I can at least let you know where they are.

When you have a tub which does not have specific spaces for a weep hole you need to ‘create’ them in your caulk line. Let me back up here a second and explain what weep holes are and why you need them.

A weep hole is basically an open space which allows moisture that makes its way behind the tile a space from which to dissipate. This is the spot that moisture can run out. When moisture gets behind your tile it will always end up at the bottom of your wall (tile installation). When it gets there it needs some place to go – to get out from behind the tile and into the tub or shower basin. That’s what the weep hole is.

Some tubs, and most acrylic shower basins, have these built into them. There is a spot about 3/4″ long that dips down from the plane of the edge and back up. It’s a dip in the edge of the tub or shower basin. When equipped with these built-in weep holes – DO NOT FILL THEM WITH CAULK! Everyone does that – they are there for a reason and no one seems to know what it is. They are weep holes. If you caulk them in it defeats the purpose of them – that will seal in the moisture.

If the moisture is sealed in behind the tile it has no place to dissipate and will simply sit there. Beyond that, the level of that moisture will continue to build with every use. The moisture cannot dissipate at the same rate that is gets back there. That’s gonna lead to a problem. You need weep holes to eliminate the moisture.Weep hole location in for a tub

When you caulk or silicone the change of plane between the tile and tub you should leave an open space – a space without caulk – in each side wall about an inch out from the back wall. If you click on that little bitty picture to the right you will see two pretty pink lines on it – that’s where those spots are.

Each of these spots are about an inch long (this doesn’t need to be exact) and contain no grout, caulk or silicone – they are simply open space. These are your weep holes.

These spaces will allow moisture to dissipate. These do not need to be the lowest spots on the tub. In other words, if your tub is not entirely level and those spots are not the lowest, it doesn’t matter. The water will end up there and run out – it is the only space to release the pressure the water will build up. It’s a whole physics thing and I haven’t had enough beer Pepsi to properly explain it – but that’s what happens. And yes, you can put them wherever you want, that’s simply where I put them.

Weep hole location in for a shower basinWhen you have an acrylic or fiberglass shower basin without built-in weep holes the same technique applies. Depending on how your tile and shower door lay out you may choose to put the weep holes toward the front of the basin, entirely up to you.

If you click the photo of the shower to the right, and ignore the fuzzy toilet seat cover,  you will see the two pretty pink lines in the back as well as pretty blue lines toward the front. That’s where I put them when I don’t put them in the back. They sometimes look better toward the front if there is a shower door there – the frame will make the weep holes less noticeable.

That’s it – longer than I expected but much easier than trying to explain with just words. If you have a question or just need something clarified do not hesitate to let me know! My blog is here to help you and the fact that I do this stuff every day will, at times, blind me to certain basic things. I do a lot of this stuff without even thinking about it and don’t realize that what is basic to me is not basic to you. If you want a post about a specific subject just let me know in the comment section of any of my posts or shoot me an email at Or, you know, send up smoke signals from your dogs back – he may have just burst into flames again. :D

There you go Kurt, tell mom you win this one and she owes you a six-pack. :D

UPDATE: I finally got off my ass and actually took some photos of weep holes in the silicone bead around a tub. These are what I’ve described above and can be used in either a tub or a shower base. There is one on each side of the tub towards the front.

Weep hole in silicone sealant around bathtubWeep hole in silicone sealant around bathtub
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  • Tim

    Hey Roger, what about one ginormous weep hole? In other words, just not caulk a tub to wall change of plane so there’s no chance of water being trapped? And if that’s a bad idea, and weep holes as you’ve described (sweet pics btw) are the move, make none in the back wall?

    • Roger

      Hi Tim,

      That’s an option, however, I prefer to silicone at least the major portion of the transition because people tend to not clean very well. Regularly. If there is an open space that large it can definitely lead to a mold issue over time simply from lack of proper upkeep. And proper upkeep on an unsealed transition is tedious and fairly unforgiving.
      The lowest points of your tub rail should be the outside corners on each end, where I’ve install the weep holes in the photos. However, you can place them anywhere you want and as many as you wish. Just keep in mind the above issue with regular cleaning.

  • Dr. Joseph Arguelles

    Hi I just rebuilt a small shower over a fiat terrazo shower pan. The walls are large format porcelain tiles over kerdi board. The space behind the tile and mortar is waterproofed and sealed to the edge of the pan. Should I make weep holes?
    What mitigates the water that gets in the weep holes? Is it just a matter of easy to get in – easy to get out?

    • Roger

      Hi Doc,

      Yes, you should make weep holes. Gravity mitigates any small amount of water that MAY get into them, negative hydrostatic pressure causes water to run out rather than in.

  • MARK Richmond

    I have a large outdoor balcony 2nd story which last year I used Ditra membrane and metal drain edge. First I red guarded the plywood then used a self adhesive black rubber neoprene thick membrane. Then laid down Ditra and put down tile.
    My balcony is not completely level from north to south but it does drain away from the house. First 6 months I did not notice any problems but then on a large rain storm the side of the stucco which is on south end of the balcony started leaking water. There also are four or five drip line that are yellowish staining my wood beam and white stucco. There are no tile popping or leaks under the balcony. I was considering routing out three 1/2″ weep holes in the side of the stucco to evacuate the water. I do not want mold to start growing and being in AZ it will dry out quickly. Any suggestions?

    • Roger

      Hi Mark,

      Weep holes will work to evacuate the water, but it doesn’t solve the underlying issue, which is essentially water management. Although the deck is not level, you are not directing the water into a specific spot to drain, it simply does so on the lowest points – wherever it wants to. Channeling water where you want it to drain is a key portion of tiling a deck. The waterproofing simply ensures water does not get below that layer, but it still needs to go somewhere. Do you have any type of gutter or channel on the low side of the deck for water to drain into and be directed away from the house?

  • Darrell Moncus

    Just had some contractors come and refurbish both bathrooms. The contractors grouted the corners of the shower as well as the space between the tile and tub (sanded grout). The corners have developed a crack on one side in each bathroom. What would you advise me to do? Should I call contractor to remove grout from corners and use caulk?

    • Roger

      Hi Darrell,

      That is exactly what you should do. Changes of plane require flexible sealant – caulk or silicone – due to differential expansion and contraction. Silicone and caulk can compensate for that, grout can not. Silicone is better and will last longer.

  • Marc

    Hi Roger,
    I am building a walk in kersi membrane shower with foam base and curb. Anyways I was wondering if you recommend caulk with weep holes where the shower wall tile meets the mosaic tile on the shower floor like you suggest above with tub surrounds. I am worried that the weephole will allow water in the shower base to always wick up the mortar behind the walls in this case where as a tub surround I expect the water to continue down to the tub more readily and not be an issue. Also what do you think about using grout to fill the weephole in the caulk?

    • Roger

      Hi Marc,

      There is no need for weep holes in that application. The water will run down the wall and under the tile on the floor into the drain.

  • Shane

    Hi Roger,

    I have those weep holes in my cultured marble shower (near the front where the sliding door is) but I’m getting water damage on the same wall that the weep hole is on. Any thoughts on what’s causing it?

    • Roger

      Hi Shane,

      Many cultered marble showers are placed directly over drywall. The drywall is normally not waterproofed, which means that any water getting behind the ‘marble’ will be soaked up by the drywall before reaching the weep holes. This can also be caused by a compromised seal at the corners and changes of plane. If the substrate behind the weep hole is absorbing water the weep holes may work in reverse.
      What is causing the damage is an improper installation of your cultured marble walls.

  • Sue Van Epp

    If the installer has sealed them up, should I open the weep hole?
    The acrylic shower enclosure even has them built in to the design.

    • Roger

      Hi Sue,

      Yes you should.