I love the creative process of remodeling! One of my favorite things is when a space is re-envisioned and reinvented into something entirely different. That’s what we did recently on a project which included creating a shower in a space that was previously a bedroom.
The first post in this series talks more about that process and shows some cool pictures of things like guys with huge gigantic concrete saws. Check it out here.
In this post, I’m going to drill down to a little bit more detail and show you the exact steps involved in creating the sloped mud bed shower base using Sakrete Sand Mix.
How to Install a Sand Mix / Dry Pack / Mud Bed Shower Pan
The majority of tile showers are what’s often referred to as a “curbed” shower. In these types of showers a curb is built up at the entry/exit point, usually out of 2×4’s and that, combined with the walls of the shower, provide a structure in which to place a rubber shower pan liner. This liner seals to the shower drain and provides a watertight “tub” underneath the tile floor in the shower. The primary reason for this is because some water will eventually get down through the tile.
But because the goal is obviously that most of the water just run unimpeded down the drain right away, the floor needs a slope toward the drain. The “mud bed” is the mechanism for providing that slope. See below.
Sakrete Sand Mix Bedding & Topping Mix
The go-to product for mud beds is Sakrete Sand Mix Topping and Bedding Mix. Available at most major retail home improvement outlets, this is a high strength (5000 psi cured) mix that is capable of everywhere from ½” to 2” in thickness. This makes it a perfect product for shower bed installations but it’s also great for things like exterior patio floor beds (bricks, pavers, tiles).
Mix With Water
All you have to add to the mix is a bit of water. If you’ve got a powerful enough drill with a mixing attachment as seen in the photo above, then that’s the easiest way to do it. Otherwise, simply add water to the mix in a bucket or a wheelbarrow and mix it with a shovel, a hoe, or whatever works.
This product takes far less water than what you might expect with concrete or even the mortar used in block and brick work. Sand Mix for shower pans is meant to be used as a “Dry pack” so the proper consistency is much like a snowball. You should be able to form the mud into a ball in your hand and it should hold that shape easily but not feel very wet.
Planning Ahead in the Shower Pan Area
In the project shown, the wall tile is already on. I’ve seen this done both ways. Often the mud bed is installed before the wall tiles. Either way, you’ll want to get about 2” of mud depth around the perimeter of your shower and set your shower drain, which usually just screws up and down to adjust, at a depth that would provide ¼” per foot slope from the farthest edge. In this case that means we set the shower drain depth at around 1.5”. (the Sakrete Sand Mix can go down as thin as ½” and perform well, but mud beds and ceramic tile specifically should be installed following ANSI, TCNA and local building and plumbing code requirements.)
Initial Rough / Loose Set
The first step is essentially just to dump the mixed up bucket of mud into the shower pan.
Note: In these pictures you can see that the installer has coated the shower pan with a thin coating of the thinset mortar used for the marble setting. This is an optional step that this (very experienced and highly skilled) installer swears by, citing a better bond between the mud-bed and the shower pan. I’ve never seen that done on previous projects and you can safely skip that step if you’d like.
The initial process is simply to spread the mixture evenly around, getting to roughly a 2” depth at the perimeter and sloping visually to the shower drain. The exact setting of both the perimeter and the slope will be handled in the next few steps. For now it’s just about getting roughly the right amount of material in the right places in the shower.
Pack Down a Level Perimeter Using a Solid Level
Not a task for a fancy wood carpenter’s level, the next step is to pack down a solid edge of the Sakrete Sand Mix mixture and to make sure that edge is level. This will be your guide as you slope the floor down to the drain.
Here’s how it is done:
- Having placed your mud mixture against the walls to your desired depth, place the level against the wall and down onto the mud as shown.
- Then use the handle of a hammer to pack (sternly) the mixture down, keeping an eye on the bubble to create a packed down, hard level mud line beneath the level.
- You can add mud along the line if you have a low spot. High spots can usually be fixed with a little firmer packing down, since the surrounding mixture is all still loose at this point.
- Do this on all four sides, making sure that the packed down perimeters are level with one another across the shower each way.
Use the Level or Straight Edge to Create The Slope Line
Once the perimeter is packed down and level, the corners are set. Using the corner as the upper point and the drain as the low point, you can now pack down a line between those two points, as shown here:
Above is a bird’s-eye view of setting the slope line using a level as a straight edge. (obviously not as a level, because you want this line sloped)
In the above image, the level is lifted up just after the packing step in order to illustrate the slope. In showers like this one where the drain is not in the center (often done so that bathers aren’t standing on the drain) there will be a steeper slope on the shorter points between the drain and the walls, this is normal.
Screed, Even Up, Trowel, Pack
After all of the perimeter is set and level, then all of the slope (corners to drain) are set, the task is to even out the mud. More mud is added if low spots are found or mud can be taken away if high points occur.
First trowel it down to roughly the right levels, then hard pack it with a flat trowel. It’s important that it be packed down and compressed so that the end result is a hard surface, not loose.
It’s advisable to double check the perimeter level on all sides after the initial hard pack. Sometimes the mixture compresses a little bit and more mud is needed.
Once the entire shower pan has been done in this manner, check to be sure there is good and even slope to the drain by placing your level over from corner to corner each way… as shown the bubble should be fairly level (it doesn’t have to be exact like a counter would be) and there should be a visible and even slope down to the drain.
Once you’re happy with the mud bed, you have to mess it up again! Unscrew the drain, raising it to the right height for your floor tile. Then repair around the drain as needed.
Set Your Tile Within 16 Hours
I didn’t know this until researching to write this post, but you should set the tile floor while the mud is still fresh, before it gets “green” in the curing process. So either set tile that day or the next, or wait until the sand mix is cured, which takes a few weeks.
For a look at more of this project and a bit of inspiration (or not, depending on your sensitivities) that you can do this kind of project too, check out the first post in this series!
Learn more at the Sakrete website!