I started this blog many years ago primarily to help homeowners through the remodeling process.
Over the years I’ve noticed a trend.
I see many installers MIXING WATERPROOFING SYSTEMS.
It is a terrible practice and leads to MANY shower failures.
What does it mean to “mix” waterproofing systems?
There are two types of water proofing systems.
A water in, water out system…where the water soaks through the tile and the mud bed. It hits a rubber liner under everything that is sitting on top of an additional slope that allows that water to get to weep holes at the bottom of a three piece clamping drain and evacuate the system.
Water in water out system with 3 piece clamping drain.
A three piece clamping drain. For a water in- water out waterproofing system.
It’s a perfectly good system but has to be done EXACTLY. No skipped steps.
Then there is a CONTAINED system where a TOPICAL waterproofing is applied to the TOP of the mud bed. The water soaks through the tile and grout, hits a waterproof membrane or paint on waterproofing (like Red Gard) and goes to the drain.
With a contained system, there is no rubber liner and no water contacts the mud bed.
This is the type of waterproofing system we use. Schluter, Wedi, etc are contained systems.
Contained waterproofing system with a waterproof membrane and a bonding flange drain.
A bonding flange drain. Used with TOPICAL waterproofing.
The problem arises when installers start MIXING waterproofing systems.
They will use a 3 piece clamping drain and paint on a topical waterproofing on top of the mud bed that has a rubber liner underneath.
With this type of drain, there is no place for the waterproofing to BOND like on a BONDING FLANGE DRAIN where the drain body itself has 3” of area for the membrane or paint on waterproofing to make a substantial connection.
Installers will build a water in water out shower system and then paint on red gard or another topical water proofing, creating a MOISTURE SANDWICH. Because this topical waterproofing has no place to connect to the drain, it forces its way BETWEEN the layers, causing BIG PROBLEMS.
The worst part is often, because they painted a topical waterproofing on the pan itself, they think it’s okay to skip putting a PRE SLOPE under the rubber liner and they won’t keep the weep holes in the 3 piece clamping drain free, which in short order causes that shower to become a sewer.
MANY showers are built like this due to poor instruction and lack of understanding.
When building a shower, YOU CHOSE ONE OR THE OTHER.
WHAT TO LOOK OUT FOR:
If you see a 3 piece clamping drain (GENERALLY) It should be a water in water out system.
If you see a bonding flange drain…It’s a contained system.
The key is —-what DRAIN is being used?
A water in- water out system OR a contained system. NEVER BOTH.
Keep your eye out!
In the video below, Jason gives a very concise explanation of this phenomenon while standing in a failed shower that we were called in to inspect.
If you see this variety of shower, it is not being built using approved methods and it is waiting to fail!
Observe the issues system mixing caused in short order in the video below: