The shower pony wall, also known as a knee wall or half wall, acts as both a divider between your shower area and exterior bathroom, and also as a method to keep splashing water from exiting outward. Furthermore, a shower pony wall is a wonderful accent piece to your finished bathroom remodel, offering a unique focal point for your tile installation.
A well designed shower pony wall in relation to the shower area is a good start before constructing the frame. As soon as you know exactly the where it will be placed and the finished dimensions, you can begin construction. There are different methods for building the shower pony wall frame, you can build the wall before securing it to your floor or you can build up starting with the wood base and securing the floor and wall as needed. For either construction, the base and top of the shower pony wall should be blocked and secured, and set plumb and square to the adjoining wall. This is an important step for when the tile installation, should the shower pony wall not be plumb and off center by even 1/8 of an inch, each tile above will continue to be offset, therefore leaving your tile symmetry off.
The structure of your shower pony wall is important in providing a solid place for added features, such as frameless glass, hand rails, or even just a place to hold onto when entering and exiting the shower area. While you may have studs running the height of the shower pony wall, you can install blocking wood to help provide support to the finished structure. Blocking wood can be added at the top or bottom in between the studs. If your shower area design requires fixtures of hand rails to be installed, the blocking will provide ample area and stability to the screws that will be used. Some waterproofing methods will require blocking to lead up the shower pony wall up to 10 to 12 inches. Local building codes would determine what is an required height. This can be achieved by cutting to size multiple 2×6 or 2×4 wood pieces.
The waterproofing method that you choose will be carried over into the shower pony wall. While the shower curb plays a major role in keeping the build up of water inside the shower area, the shower pony wall serves the same purpose with added needs. It is important to ensure that water does not enter the frame of the shower pony wall, which is why your choice of waterproofing method will be carried up the interior wall to the height of 10 to 12 inches. While this is a minimum height that is pre-determined by your local building codes, your waterproofing strategy may involve installing a water resistant membrane up the interior wall and over the exterior wall. In this case, you will need to have a paintable, preferably a flat surface already constructed, such as a backer board or cement over the wall.
Cement Over Wall
While installing a wire mesh and applying a cement scratch coat over the shower pony wall is a very secure way of ensuring your wall is plumb, it is also labor intensive and requires a skilled tradesman to get it done right. There is also counter waterproofing methods that can not be used together. For instance, applying a cement scratch coat over the shower pony wall will require a minimum 15lb. felt paper as a water resistant barrier that is layered into the shower area and carried over the wall. In this case, you would not be able to apply a water resistant barrier over the outside of the finished cement layer, eliminating the possibility of a “moisture sandwich”.
Backer Board Over Wall
Installing a backer board over the shower pony wall is an easier method, but still requires a suitable level of understanding to ensure the finished product is ready for a symmetrical tile installation. First and foremost, the frame must be plumb and square with the adjoining wall. Next the backer board must be level, if necessary during installation, shims can be used to complete this process. Only use backer board specific screws which are used for this type of installation. Make an effort to cut the backer board to the exact size of the shower pony wall, with the least amount of joints possible. Your choice of waterproofing method, installation method, and local building codes will determine at which point you stop installing screws into the backer board. It is suggested that you never puncture the water resistant barrier and even less below the shower curb, but you may be left with bowing walls at the bottom of your shower pony wall. The rule of thumb is to stop 2 to 3 inches above the shower curb. The alternative would be to install the least amount of screws as needed and mud pack the openings with a thin set, deck mud, or silicone. You can further use a fiber mesh over packing and to further protect the exterior from water seepage, you can apply a liquid waterproofing membrane over these punctures
If you put a sufficient amount of effort into the design and planning stages of shower pony wall, the construction and installation stages will be much easier and provide you with a great finished product.