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.
Since I’m just a tile guy I”m not usually up on all the new technological crap that has nothing to do with tile, like online video or the ‘SlapChop’. I’ve decided that since I spend most of my days in other people’s showers that I should get out more and learn something else.
So naturally, since I own kitchen knives, I decided to make a video about a tile subject. So here is my first video, sans sound because in audio I sound like a drunk leprechaun, for my readers. Umm – that’s you.
And since I actually have a day job and bills to pay all you get is a time-lapse photography of the creation of a mud deck for a tiled shower floor. But I’m gonna call it a tile video ’cause Google loves that shit.
Once you have your entire perimeter done you simply need to pack deck mud into the rest of the base from the perimeter to the drain. Once again – beat the hell out of it. Seriously, pack it in there really well. The more dense your floor is the better. You need to ensure that the line of the floor is straight from the wall to the drain all the way around without any major humps or dips. It takes time and patience – use both. This step is critical since this is the substrate your tile will be installed upon.
Well now we’re ready to waterproof your curb. If you have reached this post before reading the previous two, start with How to build a shower floor from the beginning. Now that you’re ready to get the curb cut and waterproofed lets get it done.
And yes, I know my pictures suck – I’m a tile guy for cryin’ out loud, not a professional photographer. Until you try to balance a liner, a razor knife, a margin trowel, and a camera while trying to take a photo don’t give me any crap about it. Oh, and you can click on any of the images for a full-size version – partake in the full glory of how much my photography sucks.
We need to start by finding the inside lower corner of your shower pan and making certain that the liner is pressed firmly against it. Then follow it up the corner of the curb and wall to the top inside corner of your curb. This is the spot at which you will start the cut in your liner.
Now that you have your curb built and your pre-slope done (if you haven’t done this yet check out How to create a shower floor, Part 1) you are ready to install your waterproof liner.
Purchasing a waterproof liner
When you order or buy your liner you need to get one large enough for your shower. The liner you get has to be at least one additional foot larger than each of your measurements. For instance, if your shower floor is three feet by five feet your liner needs to be four feet by six feet. This allows enough to run the liner up the wall behind your backerboard six inches each way. You also want to purchase two “outside” corners for your curb. These are pre-formed corner pieces to waterproof the ends of your curb after you cut the liner.
I usually order mine two feet larger in each direction. Six inches is the minimum. Specifications state that your liner must run up the wall at least three inches above your curb. So if your curb is three inches high your liner needs to run at least six inches up each wall. I usually go a foot above the curb – overbuilding your shower is rarely a bad thing.
The following five-part series gives a basic overview of building a shower floor for tile. If you would like a complete step-by-step of the entire process with all the little idiosyncrasies and details I now have manuals describing the complete process for you from bare wall studs all the way up to a completely waterproof shower substrate for your tile.
There are a couple of options to create a shower floor for tile using deck mud. The first is a single-layer shower floor which can then be coated with RedGard or a similar product or covered with kerdi to waterproof it. The other is a normal shower floor with a liner which will have two layers – a preslope, the liner, then the top slope which is then tiled. This series of posts will describe the latter.
Before we start I should note that unless you are using the kerdi waterproofing method or utilizing a liquid membrane as your floor liner you should not have the backerboard installed in the bottom part of the shower. Your waterproof membrane for a shower floor will be installed behind your backerboard. The curb and pre-slope need to be completed before installing the lower wall substrate.
Creating the curb for a wooden floor
The first thing you must do is create the outside curb of your shower. You need to create the “box” which will become the inside of your shower floor. Depending upon whether your shower will be created on a wood or concrete floor will dictate what material you use for your curb.
If you have a wooden floor you want to use regular dimensional lumber. The 2 x 4’s they carry at Home Depot – those. That is the easiest and most readily available material. Ideally you want to use kiln-dried lumber. That is lumber that is, well, dried in a kiln. By removing moisture in this manner the moisture content of KD lumber is normally between six and eight percent compared to regular dimensional lumber at close to 15%. Why does that matter? Well moisture and wood don’t mix. As it dries wood has a tendency to warp and twist. The less moisture initially in the wood the better. KD lumber is best and regular air-dried dimensional lumber is also acceptable. NEVER use pressure treated lumber – ever.