A shower dam, also referred to as the shower curb, is the raised section at the entrance to the shower that keeps the water in. In this article, we will discuss some regulations and methods for replacing an old shower dam or building a new one.
The first thing you have to be aware of when working on a shower dam is your local building codes. Some local codes say that curbs must be from 2 to 7 inches high. Be careful though, because I have seen other codes that state dams or curbs must be 3 to 9 inches high.
Most local codes will also specify that dams should be a minimum of 30 inches wide as that is the minimum width of the shower entrance. However, some codes specify a minimum of 36 inches wide. If you want to go the safe route without referring to your local code (which I do not advise), you can make a common 4 inch high dam that is at least 36 inches wide and it will most likely satisfy any local code requirements.
Building a New Dam over an Old One
A lot of times while remodeling your bathroom, it becomes necessary to change out the shower tiles. While doing this task, you will run into the shower’s dam. To redo the tile on the shower dam, it is common to remake the entire dam. What is done is the new dam is built directly over the old one. The common way of doing this is to use a length of lath wire (a wire mesh) that is equal to the width of your curb or dam.
The lath is molded over the old dam forming a U shape. Then tack the lath onto the old dam from the front only. Do not puncture the dam on the shower side or the top as this may cause leaks.
Now you are ready to apply your mud. Apply about an inch of cement to the top of the curb. Then use a flat edge and form the top edge. Once you have all 3 sides formed in a similar fashion, you will let it set. Then remove the flat edges and you will have a new cement dam that is ready to tile.
Making a New Curb or Dam from Scratch
Of course if you are making a new dam, it will be done a little differently. First, make sure you adhere to the local codes mentioned above. You will need a base structure to build the dam. You want to select a base that will allow you to add about one inch of mass to each side and the top of your curb. The bottom will remain untouched.
Usually stacking 3 2x4s will give you a nice sized dam base. You can also use different sized boards or bricks for your base. Once you have your base, continue to build your dam in the manner described above. The steps are the same as if you were covering an old dam. The only difference is that you are covering a wood or brick base instead of an existing curb or dam.
Photo by Bart Everson, Creative Commons Attribution License