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!

{ 35 comments… add one }

Leave a Comment

  • Daniel Westfall

    Hey Roger, as a young tiler I just wanted to say you are an inspiration. Thank you for your amazing content.

    • Roger

      My pleasure Daniel! Thank you for saying so.

  • Aaron

    Wasn’t sure where to put this, but are you still selling your different tiling books?? I was trying to purchase one, but kept getting the error below. I’ve tried from a phone, ipad, and windows computer with chrome. Any ideas?

    ***** Received Error *****
    Access Denied.
    You don’t have permission to access “/cgi-bin/webscr” on this server.
    Reference #1641009194c568bd8829c3b0301d519
    Timestamp: 1641009194

    • Roger

      Hi Aaron,

      Yes, I am still selling them. I have been arguing with paypal about this for over a year. It is something to do with their proxy, which is a sort of firewall between here and their site. These are the solutions they’ve given me, unfortunately it’s all on your end:

      1. Clear your browser cache, a prior visit to paypal stored in your cache red-flags the ip in their system
      2. Use a different browser to access the page. Same as the cache issue above, but your ip would not be shown in an already existing ‘cookie’
      3. Try multiple times

      These are ridiculous to me, but I don’t run paypal. Most people have been fine with 1 or 2.
      Some have been able to order a different manual than the one they’re trying to buy (it’s a different purchase button). If that ends up working let me know and I’ll just send you the correct manual after your purchase.
      Some have been able to click the order button, which adds it to their cart, then go back to the page and click on ‘view cart’.
      It seems the easiest is to try and order from a different device. If you’re trying from your phone, try from a laptop of tablet.

      I have done everything I can from my end to resolve this, paypal doesn’t seem to have any concrete answers for this. Sorry for the issues, paypal is frustrating as hell sometimes.

      • Aaron

        Thx. I was able to get the Kerdi walls with tile tips to work tonight, but would prefer the traditional walls guide if that’s possible. PayPal was through my wife’s account (Natalie). Looking forward to devouring the info, thx!

        • Roger

          Just sent it. If you have any issues at all just let me know.

      • Jose Pinon Guizar

        Hi Roger do you know the measurements from that fabric flange? I need to mud my floor before fabric arrives

  • Cody


    I am so lucky to have stumbled here! I was wondering if it would be possible to use the divot method with a linear drain? I want to use a 36” x 2.75” linear drain and kerdi membrane. I was thinking:
    1) I would use 1.5” or 2” foam (as someone in the comments suggested) to form up my “divot”. Maybe it’s better described as an axe wound? (*childish snicker*)
    2) My blocking would be 38” x 6” (6” wide to accommodate the drain clamp) and then I would carry my mud up from there 1/4” per 1’. It will have only 2 slopes with the drain being centered
    3) I would install waterproofing, then my drain, pea gravel around the weeps, then mud my divot.

    My questions:
    1) Would that work or am I at risk of exploding kittens and other four legged friends?
    2) I was thinking I could lay my membrane as one solid piece starting first in the recess and then up and over the mud bed, but worry the inside corners of the recess could cause trouble?
    3) What am I missing and/or how would you improve on this plan?

    Thank you so much in advance if you answer! If not, thank you a ton for everything you’ve provided anyway!

    • Roger

      Hi Cody,

      1. Yes, it would work just fine.
      2. They could cause issues but you can paint over those corners with redgard over the membrane to ensure they are waterproof.
      3. I would use a topical linear drain. :)

  • Sissy

    Your instructions is what I have went by more than anyone’s that I have researched I appreciate it. I was wondering when I fill in the divot do I let that dry as long as my shower pan took to dry? And my dried shower pan is not so smooth can I go back over it with some wetter dry pack?

    • Roger

      Hi Sissy,

      The dry pack you put in the divot should be just fine to tile over the next day. Wetter dry pack won’t work well, but you can skim over the top of it with some thinset to smooth it out.

      • Sissy

        Thank you so much! Before I seen your response I tried wetter dry pack lol yes definitely doesn’t work to well for an amateur at least. I really do appreciate you.

  • Megan

    Hi Roger,

    We removed the shower pan from our downstairs bathroom over the weekend. Underneath was bare slab, with a 10×12″ opening. There is dry, loose dirt surrounding the drain about 8-10″ below the top of the slab. We are planning to replace with a Kerdi shower. What is the best method to fill this hole? House was built in 1990, daylight basement in a dry area of Washington state. Thank you!

    • Roger

      Hi Megan,

      Just mix up some deck mud and fill it with that. You can use just regular concrete, but any movement will lead to cracking over time, deck mud won’t do that.

  • David Dolch

    Hi Roger,
    I have used your books (or whatever you call them) to do two Kerdi showers, three Ditra bathroom floors, and a Ditra Heat kitchen floor.

    My dilemma is with my kitchen backsplash. It will be tile over drywall, using Mapei Porcelain Thinset. My question is should I prime the drywall or not. Some people say yes, it will prevent the drywall from absorbing too much moisture from the thinset. Others say no, because the thinset will bond better to the unprimed drywall.

    What do you say?


    • Roger

      Hi David,
      I wouldn’t bother. The porcelain thinset is modified so it retains moisture. Bare drywall won’t be a problem.

  • LaNell Barrett

    I carefully studied your e-books, everything about your shower and tiling advice (particularly the waterproofing). Before my gut to metal studs and redo of shower a few years back (we have metal studs in SW Fl)
    Wish I could post photos 😁…
    But my thought has always been why did it have a 12″ x 14″ divot mess to begin with? It certainly is not what I turned it into. Oh, and I have a photo of my foot next to that gaping hole full of sand and a few hairy roots. Really funny.

    • Roger

      Hi LaNell,

      Not sure what divot mess you’re speaking of? If there was a large divot that size filled with sand it was because concrete needed to be removed in order to plumb a drain pipe to the area after the slab was already done. Is that what you have? If it was growing roots it was either due to improper waterproofing (VERY likely in florida, as they don’t think a concrete floor needs to be waterproofed) or a moisture issue below the concrete.

  • paul

    hi Roger,
    awesome site and thanks for helping us DIYers. i plan on redgarding entire shower or maybe not the floor depending on your answer :)
    i completed the preslope with chicken wire and its just under 1/2 inch thick at the drain, but havent installed the cement board walls yet or applied any redgard yet. i did put plastic sheeting under the preslope to keep the moisture from the preslope mud being soaked by the subfloor. i also have an outside wall with vapor barrier over insulation. i was planning on doing the traditional pvc liner when someone told me about the divot method which led me to your site.
    1. custom building products told me that redgarding the outside wall which already has the vapor barrier will not cause any issues with mold (mold sandwich) whats your thoughts?
    2. is the plastic sheeting under the preslope any concern for a mold sandwich when the pvc liner or redgard is applied over the preslope?
    3. do you recommend the divot method over the pvc liner? if so, can i just add the additional layer of mud on top of the preslope and use a bonding agent in the mix instead of water? if not, i can rip out the preslope and start over.
    4. when i install the cement board walls, is it ok to sit them on top of the pan since it will be redgarded down and over the floor, with 6″ membrane fabric?
    thanks again

    • Roger

      Hi Paul,

      1. No, it will not cause any issues.
      2. That also will not cause any issues (the plastic should not be ‘sealed’ or tied into your wall waterproofing).
      3. No. You want one or the other (pvc or redgard), never both – that will cause a mold issue.
      4. Yes.

      I’m a bit confused. If you are going to do the redgard you need to add a full top mud deck (with divot) to your preslope (the preslope was not needed with a topical waterproofing, the divot is to allow use of a three-piece clamping drain with a single deck). I believe this is your plan, but you keep mentioning a pvc liner…?

  • Mark

    Hi Roger, Ray wrote:
    1b. Gluing the the three piece flange to the drain pipe so the bottom of the flange is 3/4″ above the plywood sub-floor then installing the deck mud to a depth of 3/4″ so it is even with the flange, then adding the divot and completing the deck to a depth of 1 1/2″ with the 1/4″ per foot rise to the wall. Then proceed as described above.

    and you replied this method, “1b” is the proper method, but in your photo, it appears that the flange is flush with the plywood, i.e. no 3/4″ of airspace between the flange base and the wood. Please advise … just looking for clarity, not trying to nit pick.

    • Roger

      Hi Mark,

      No worries, that isn’t very clear. If the flange is flush with the plywood it’s fine, the thickness of the mud bed around the drain would be 3/4″, the the divot dives from the perimeter of the drain down to the flange. You would have a 3/4″ deep divot around the drain.

      If, in fact, his drain sat 3/4″ ABOVE the subfloor, the thickness of the mud bed around the drain would need to be 1 1/2″ – 3/4″ up to and under the drain, then 3/4″ above that to create the divot I described above.

  • Ray

    Hey Roger,
    I really like the website, and appreciate all the great information. I would prefer to only do the work once, and most importantly keep our dog from bursting into flames.

    Which leads me to the following questions:
    1. When using the divot method with liquid topical waterproofing, which is preferred method for installing the drain flange?

    1a. Mounting (to include the proper ABS glue/cement) the three piece flange directly to the plywood sub-floor then installing the deck mud to a depth of 3/4″ to 1 1/2″ with the 1/4″ per foot rise to the wall. Then proceed as described above.

    1b. Gluing the the three piece flange to the drain pipe so the bottom of the flange is 3/4″ above the plywood sub-floor then installing the deck mud to a depth of 3/4″ so it is even with the flange, then adding the divot and completing the deck to a depth of 1 1/2″ with the 1/4″ per foot rise to the wall. Then proceed as described above.

    2. When using a liquid topical waterproofing membrane (Mapei Aquadefense), is there such a thing as too thick, as long as you wait the required amount of curing time.
    2a. I plan on using the trowel method to apply the waterproofing and had considered a third coat applied via roller as extra insurance.

    Thank you,

    • Roger

      Hi Ray,

      1b is the proper method (even with the lower flange, of course). There is such a thing as applying too much AT ONCE. Using the trowel method I use a vct trowel (1/32″, I believe) and put a coat on with the ridges, let it cure (so you have dried ridges), then go over it with another coat with the flat side of the trowel to fill in the ridges. Once cured you have the correct thickness. A third coat is unnecessary, although it won’t harm anything as long as it isn’t a REALLY thick coat.

      The problem with too much at once is that once the top of the layer cures the underlying membrane cannot cure because it requires air. Once the top cures air cannot get to the stuff beneath to allow it to cure.

      • Ray

        Perfect, thank you for the quick response. I think I have everything I need to to do it right the first time and keep our dog from bursting into flames (she is too old for that much excitement). I know where to find you if I have any questions.

        I will follow the process outlined in the the Liquid Topical Shower Waterproofing manual (3/16 V-notch trowel) and wait the full cure time before adding the second and third (maybe) coats. The shower is not going anywhere and I’m not under a real time crunch (my wife may disagree on this point), and as a friend once told me:

        You can complete any project: Better, Faster, Cheaper… Pick any two.


  • Tom

    Just found this website, love the humor and the detailed explanations including exploding K-9’s.
    1. Can the divot tool be fabricated from a piece of Owens Corning R10 foam board? It’s 2” thick, should it be cut down to 1 1/2” thickness? What would a minimum depth be for a divot to work? What diameter should the divot tool be?
    2. Are there any downsides to applying a 30w felt paper to the whole bathroom floor directly on top of plywood before applying the cbu on top of that? Would my feline explode?


    • Roger

      Hi Tom,

      Yes it can be fabricated from that. Thickness doesn’t matter as you don’t have to mud flush to the top – it can stick out higher than the mud. Minimum depth would be whatever the depth of your mud happens to be at the drain. It should be at least 1″. Diameter should be a minimum of 6″, 8-10″ would be better.

      Not really any downsides, but not necessary, doesn’t gain anything and is a waste of time and money. But sure, tar paper away. :D

  • 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.