The Divot Method

What is the divot method?

The divot method is a way to utilize a regular three piece clamping drain with a topical waterproofing product. Topical waterproofing includes sheet membranes such as Schluter Kerdi and liquid membranes such as Laticrete Hydroban or Custom’s Redgard.

What you need to know:

If you are familiar with waterproofing a shower floor with Schluter Kerdi, or any other topical membrane, including liquids, you know that you need a topical drain. These differ from a regular clamping drain because they do not have an integrated weep system.

Don’t have any idea what that means? Then you need to do more research before you attempt to build and waterproof a shower floor. Seriously. You need to know what you are working with before building a waterproof box (your shower) inside of a wooden structure (your house) and expecting it to prevent damage that could compromise the structure (your bankruptcy). You can start with my free waterproofing manual. It will give you good overall information on the various waterproofing methods.

A clamping drain has integrated weep holes below the barrel, or central, part of the drain. Any water that does not go into the top of the drain (the strainer, the portion you see) will make its way down to the weep holes and into the pipe. A topical drain channels all water into the top of the drain. If you DO know what that means, then I’ll explain how you can use a 3-piece clamping drain with a topical waterproofing membrane. That’s what you’re here for, right?Location of weep holes in a clamping drain

The way to use a clamping drain with a topical waterproofing membrane is with what is called the ‘divot’ method. The divot method is a way to tie the weep holes in the drain, which are BENEATH the top of the deck mud, into the waterproofing on top of the shower floor.

The ‘divot’ is exactly what it sounds like – an impression around the drain. The sides of this impression slope from the top of the shower floor (where the waterproofing is installed) down into the weep holes of the clamping drain. By tying the waterproofing of the surface membrane into the waterproofing down the sides of the divot and into the weep holes any water not entering the top of the drain will run down into the weep holes. This divot, once waterproofed, is filled with deck mud.
The shower floor utilizing the divot method will look something like this horrible graphic here:Topical membrane with divot drain

And here’s what it looks like with a liquid membrane as the waterproofing.Divot method with liquid membrane

If you are using a sheet membrane it is best to use what is called a ‘hat’. This is a membrane material formed in the shape of a…wait for it…hat! A sombrero, specifically…Noble drain flashing

It comes without the hole in the center, you need to cut the hole to fit against the outside of the bolts in the lower flange of the drain.Noble drain flashing

This is installed with thinset, just like the kerdi membrane, and once cured forms a waterproof seal from the surface down into the weep holes. One of the most common products used for this is the Nobleflex drain flashing (the gray things in the photos above).  It is available in five sizes, the two most common being ¾” or 1 ½”. This indicates the depth of your mud bed at the drain. So if your mud deck is 1 ½” deep at the drain, you need the 1 ½” drain flashing.

You can use nearly anything to form the divot in the mud. A small frying pan, a mixing bowl, if using a hat you can place it down there and just pack mud around it. Anything that will form that impression will work just fine. I highly recommend the drain flashing tool. It is that pink foam thing you see in the photo below. It works really well.Noble divot tool

You can also use a liquid membrane if you are using a sheet membrane over the floor. You just paint the liquid from the weep holes up the sides of the divot and onto the surface of the sheet membrane.

Whichever method you choose you need to ensure that your waterproofing is installed directly up against the outside of the bolts in the lower flange of the clamping drain and is then sandwiched between the upper and lower flanges exactly like a regular membrane would be. This way water will flow from the surface membrane down into the divot and into the weep holes. You want a continuous layer of waterproofing from the surface of the shower floor all the way into the weep holes.

The graphic below shows an exploded view on the right and the way it all fits together on the left. See how the membrane is sandwiched between the upper and lower flange? Like that.

Once the waterproofing is completed you need to place something around the drain flange to ensure that deck mud does not block the weep holes. Pea gravel works very well, as does a ‘weep hole protector’ (it’s that clear thing you see in the photo below).

Once that is in place just fill the divot with deck mud flush to the top of the shower floor and tile directly over it up to the drain. DO NOT waterproof over the top of the deck mud filling the divot! That seals up the weep holes and defeats the entire purpose of all this work.Weep hole protector

The short list of steps necessary for the divot method:

Assuming you already have the basics down as far as creating a shower floor for tile (click that link – it’ll give you the overview), there are only a few differences. If you read through that link above, the one for the regular shower floor (traditional liner method), the main difference is that you only need a single slope, or the preslope. Once created your topical waterproofing will be installed directly to that.

Before you begin packing mud for your shower floor you need to have the drain installed with only the lower flange of the drain assembly. You then place your divot ‘form’, whatever you’re using to form the divot – pan, mixing bowl, the pink foam divot tool I mentioned above, etc. – over the lower flange in order to pack mud against it to form the divot.

Then just pack all the mud in there as you normally would for the preslope (in the link above). Be sure to pack it well against your divot form so that once cured the walls of the divot are solid.

Once the deck mud is cured, remove your divot form carefully. It is usually better to slowly twist it back and forth out of the divot rather than trying to pull it straight up. You should have a (fairly) perfectly formed divot around the lower drain flange.Shower floor divot

Pretty, isn’t it? :D Then…

If you are using a topical liquid as your waterproofing:

Just paint the waterproofing liquid with the required thickness over the entire shower floor, including down into the divot and ONTO THE LOWER FLANGE OF THE DRAIN, up to the opening.

Once you have the required coatings and they are cured, install the top half of the drain flange, put your weep hole protection in there (pea gravel, weep protector, etc.), insert the threaded ‘barrel’ portion of the drain then fill the divot with deck mud flush to the top of the shower floor.

If you are using a sheet membrane as your waterproofing with the drain flashing:

Cut out the hole in the flashing (hat) to fit snugly against the outside of the bolts in the lower drain flange. Install a silicone bead around the outside of the bolts onto the lower drain flange. Comb thinset from the perimeter of the drain flange, up the sides of the divot and out onto the shower floor enough to reach the edges of the flashing once installed. 

Place the flashing (hat) down onto the drain, press firmly around the flange in order to embed it into the bead of silicone. Embed the rest of the flashing into the thinset around the drain, up the sides of the divot and out onto the shower floor. Install the upper flange of the drain assembly and tighten down the bolts.

Install your sheet membrane onto the shower floor and over the edge of the drain flashing, all the way up to the very top edge of the divot (where it meets the shower floor).

Once finished  place your weep hole protection into the divot around the drain flange (pea gravel, weep protector, etc.), insert the threaded ‘barrel’ portion of the drain then fill the divot with deck mud flush to the top of the shower floor.

If you are using a sheet membrane on the floor with a liquid waterproofing for the divot:

Begin by installing the sheet membrane over the shower floor up to the very top edge of the divot where it meets the shower floor. Once that’s installed paint your waterproofing membrane from the very edge of the drain opening on the lower flange all the way up the divot and onto the membrane on the shower floor a minimum of four inches around the outside of the divot. Repeat with as many coats as needed to achieve the required thickness of the liquid membrane.

Once you have the required coatings and they are cured, install the top half of the drain flange, put your weep hole protection in there (pea gravel, weep protector, etc.), insert the threaded ‘barrel’ portion of the drain then fill the divot with deck mud flush to the top of the shower floor.

These are the very basic steps for utilizing a three piece clamping drain with a topical waterproofing. I can answer any specific questions below, because not every project is going to be so basic and every installation will have different aspects. I obviously can not cover every scenario in one blog post, but I will help if you ask a question in the comments.

If you need instructions on the rest of the steps for your shower installation with topical waterproofing membranes just head on over to the Library and pick up one of the manuals for your specific shower. We have every waterproofing type in there and each manual is detailed from the start of your project to the finish.

With, of course, some horrible humor and adult beverages thrown in. Because when you’re building a shower – you absolutely need both!

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  • JoLynn Dixon

    Hi Roger,
    I used your instructions to rebuild my last bathroom in my previous house. Your instructions are so detailed that I was able to build it perfectly with no previous experience. thank you! Now I’ve purchased a new (old) house and curious if I can use the divot method to replace a drain over existing flooring where I am laying new tile on top of old tile? Also, do I need anything other than thinset between the new and old tile?

  • Tim

    Hi, Roger. I’ve been reading stuff on here periodically, and definitely have learned a lot. I finally picked up a three-pack of your ebooks today (Liquid Topical Shower Waterproofing, Tile Tips, and Tile & Stone Installation.

    So … I started doing serious research about shower pans etc well after my father-in-law and I had already laid out the room, and he had already put down concrete board on the shower floor and installed the drain. I learned subsequently that’s not really how it’s done.

    Anyway, my thought is to treat the concrete board like a concrete floor: i.e. throw down a thinset slurry and put my deck mud over that. Would you say that sounds workable?

    I have two 3 1/2 gallon pails of USG liquid membrane (a $60 steal from Craigslist), but have a conventional type drain so will need to use the divot method. Where would you recommend a DIYer pick up pea gravel, and would I be seeing it under that, or another name?

    • Tim

      I forgot to ask something else about my drain. When I look at the lower part, I’m not all that confident where the water is going to drain, while the upper (middle, I guess) part has four holes, through which I can see the vertical drain pipe. (This is the drain on Amazon: Note that I’m not using the white threaded insert as the finish part of the drain I’m using is not threaded.)

      Would it make sense to silicone the lower and middle parts of the drain together, and use those holes as weep holes?

      • Tim

        Hm … doesn’t look like my photos attached. Maybe one at a time?

  • Matt

    Hey Roger!

    First, thank you for all the great info! I am constructing a shower via your instructions, but have hit a bit of a snag.. I removed an old bath tub/shower which had that typical three piece plastic garbage shower surround kit which was glued to various pieces of OSB that had been skimmed off plaster. Anyway, I ripped that all out and now I have three plaster walls. The walls are in good condition minus some glue/paint/trash OSB remnants and a few nail holes from what they used to shim the plastic tub surround out with. My questions are these:

    1)Can I leave these in place when building a shower pan via the traditional method? My throughts were that I could use the walls as essentially stud equivalents, and run the rubber liner up them. Then attach hardie board directly to the plaster, and overlap the rubber liner as usual.

    2) Permitting that is acceptable, could I then redguard the hardie board?
    So, this is kind of like combining the traditional shower deck method with a liquid topical membrane.

    3) Which books of yours would accommodate this kind of endeavor.

    Thanks so much!


  • Mike

    I just found your website, and I am glad that I did. We used to do the “old school” mud pan for many years and I was having a conversation with a colleague about the proper ways to create. Very informative and the descriptions are easy to understand and follow.

  • Nick


    Great website, thank you for all of the information. My question is concerning the divot method and shower pans. I have followed your directions for installing the traditional liner and preslope and have done so successfully. I have also installed the lower panels of hardibacker so I can put my next layer of deck mud over the liner. However when inspecting the liner it appears my preslope in one area is not as it should be and there is water sitting next to the drain that cannot reach the weep holes. Clearly I messed up and did not do my due diligence. In order to remedy this I was hoping to get your input.

    1. Should I take off the hardibacker pull back the section of liner and try and repair the slope with thinset and deck mud like you had mentioned in a previous post.

    2. Cut out all the liner and do the divot method and waterproof with redgard. Regarding this my question was how thick the foam divot form comes in; ones I saw looked to be 3/4”, not sure if they made a 1 1/2” one.

    3. Some other solution.

    Thank you

    • Roger

      Hi Nick,

      Pulling off the cement board and repairing that spot would be your best bet. If the spot is less than 1/4 low or so you can likely just fill it with thinset, otherwise the thinset and deck mud.

  • Clip

    A friend recommended your site to me for advice on building a shower. I really enjoy your sense of humor. Everything is going great (I think) so far. I’ve got the first layer of deck mud down. I’ve got the lower portion of the drain in and put 2 coats of red guard on the deck, walls, and curb. I’m now trying to figure out how to install the upper portion of the drain. Mine is square, not round. I had a really hard time finding one anything like this. I had to go to 2 Home Depot stores to finally get the one I have. There’s a picture of it here: I’m thinking it’s going to be tricky screwing that square thing down on top of the tile without leaving gaps in the shape of a circle. What’s the trick to getting that drain level with the top of the tile?

    • Roger

      Hi Clip,

      You will just need to get the height correct before installing the tile. Set the tile next to it, keep screwing it down until you are about 1/16″ above the tile (to compensate for the thinset which will be under the tile), then just leave it there until you tile.

  • Matt J Mulhall

    So, I fully understand the concept. My concern is the additional day for curing when you fill the top of the divot with mud. I am in the practice of using a few handfuls of rubber like small plus shaped spacers around the drain to prevent the mud fro clogging the deep holes. Are you suggesting my method is not adequate? Or are you just platforming a method that is surefire failsafe. I am all about overkill, 30 yrs experience. Seems that extra day may cost me. Your thoghts please. Thanks, Matt J Mulhall

    • Roger

      Hi Matt,

      I believe you’re confusing this method with a regular traditional installation with a liner. The spacers around the drain are just fine to keep the weep holes open, that seems to be the gist of your question. However, this divot will be a MINIMUM of 1 1/2″ deep from the surface of the shower floor to the bottom flange of the drain where the weep holes are located. It needs to be filled with something in order to have the tile flush across the top of the divot.

      With the traditional method the entire top slope of the shower floor is placed over the flange and spacers around the weep holes. Can you explain to me what you’re asking here?

      • Matt J Mulhall

        Thank you for replying. I believe I am a bit confused. I need to reread it and envision. Yes, I am a customer to using liners, old school, over a prepitch, whether over concrete or decking. Always keep the depth around the drain at min 1 3/4. Inch and Taper it back according to shower dimensions, distances ect. I install my own liners, usually Clorolay, but occasionally Oaty, but always 40mil min. I must be missing something, I will reach out if I have more questions on this. Thank you for your time.