How to build a proper shower base is critical to prevent having water damage, black fungus and mold issues developing in your home.
Building Shower Base
Building a shower base is a lot simpler than most people would think. There are a few different options, but I find that one works better than all the rest. Below I will list three main ones that I run into all the time.
- Membrane with compressed sand
- A cement base and membrane
- Schluter Shower Kit system
The membrane with compressed sand is medium in total floor weight for heaviness on upper levels for residential homes. This system is the most problematic of all the types I have seen around. You see from an install perspective it is one of the quickest and easiest to do. The problem is it can cause the most damage and problems when done wrong and left in place for too long.
If you use a particular product that has the silicon sand in it, you just shape the sand bed ( dry pack) to the required size and slope of the shower stall. You would then wet the sand that would take away its mobility and cause it to harden or stiffen up. Your doing the same principle as a rock patio outside where you would use this product as grout between them. For the final part, you would apply your rubber membrane over top of the sand and seal it at the drain and all your walls and curb face.
The problem is most installers place the rubber waterproofing underneath the sand to make their job easier. When water gets past the tile and grout on the floor, you start to get that funky smell, and the problems continue from there. One of the main reasons installers will do this is to avoid the possibility of the membrane on top of the sand bed from getting a puncture causing a leak.
Personally I never use this system; I only rip them out due to failure.
A cement base and membrane tend to be the heaviest of these three types. This system works well when it is done right. I find that this system can take the longest to install due to the
thickness of your cement bed depending on the size of the custom shower.
Depending on which products you use and the design of the shower this method requires more cure time before you can start applying the membrane to the finished floor tray. The larger the shower, the more you need to set the grade causing a thicker bed along all the extremities. This thickness will determine how many hours, days or layers it will require due to product type.
Any problems of leakage from this kind of base directly come back to what did the installer do wrong when sealing up the membrane to the base, drain and walls. There are rare cases from improper mixing of the base product for creating the tray; this causes the pan to broke up so the membrane will lose its seal and cause a leak. I’ve never seen one but have heard of it, usually improper membrane installation.
This system I have used on concrete floors where weight is not an issue on basement floors for residential and mainly in condos.
Schluter Shower Kit system is the lightest weight system to use with a expanded polystyrene foam. This system is one of the most widely used systems that I have seen and knew existed. Other companies using the same principles in design and application just different colours of membrane and names for the product exist as well.
This system can be modified to fit different designs to accommodate your requirements. This system is fast and easy and comes with its membrane product as well called kerdi and is set up with two types of efficient drain systems. One type that is original requires 4″ inch tiles or smaller to slope all around the drain for proper water flow. The second is a newer design that allows for the larger format tiles to slope to a trough type draining system.
Again if you are going to have any issues with this kind of system, it is usually errors made with the membrane sealing process method used by the tile setter during installation.
This system is the one I use most of the time for creating regular or custom showers.
Building the shower base
Whenever I do a shower using the Schluter system, I always try to get the base package that is the closest in size and style.
- Remove a tub I use the offset tray 32″ x 60″ inches
- If it is a new shower than the centre drain system works 32″ x 60″ inches
- You can also get a 48″ X 48″ inches try for square showers
Now let’s say you need only a 42″ x 42″ inches then you can centre up the drain and cut of the perimeter excess that you do not require to change the 48″ inch square tray into a 42″ inch square pan.
If you need a neo-angle shower tray, you just measure up for your drain again and cut away the excess perimeter sides again.
Let’s say your tray is the centre drain 32″ x 60″ inches after measuring up the drain location it’s fine, but you see your not big enough to fill from wall to wall because this new shower measures 42″ x 72″ inches, what now. Well your not able to buy a larger kit so this is what you do. Cement your tray and curb in where they need to be and fill the extremities with a floor leveller good for a 2″ pour. Leave it for the day so it can cure then use another product like “Sand Topping Mix Quikrete” that you can feather from basically nothing to a sloping grade that will cause the water to run to the drain. You can usually follow the slope from the tray itself and continue that grade to the wall and once that sets you are done creating your custom tray.
What it boils down to is if you’re lucky you can use the tray straight out of the box, or you will be customizing the tray the way I do 98% of the time. I’ve had people request I create an “L” shape trays angled something like a hockey stick etc. Anything is possible, it’s all up to the design you want to have installed.
So when it comes to building a shower base, you have some different options but I would suggest using the Schluter shower kit to get yourself the actual professional look and security of knowing you have a waterproofing system that’s been tried and test proving that it works. All you need to do is make sure that you have it installed correctly.
For more information on this go to Schluter Shower Installation
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