Happy New Year & Hello. Schluter ?

[Melanie's Eden]

I would like to introduce myself, I have been a voyeur of sorts on this site for a very long time. Thank you to all that have un-knowingly helped me along the way. I have thus far had an interesting life as an entrepreneur, furniture designer [& much more]. Flipped many homes along the way; always did my own work. With that said, I am no stranger to tile. I would say in this day & age, I would regard myself as old school.
I have never worked with the Schluter system but have read about everything they offer. At the end of the day I have one question that I have yet to read in all the data I have come across. Hence my need to finally join this forum.
If all mud is porous to some degree then what stops the thinset [as used to affix the bandings] from wicking moisture.
I can not wrap my head around this. If the banding [& I know it is not] was set in a silicone, I would think it better. [I am not proposing using silicone, just that I would understand it better] Can anyone help me to understand this?

[Tool Guy - Kg]

Welcome to the forum!

To answer your question, it helps to think of a freshly waxed car. Does rain water or hose water sprinkled on it cover the whole surface in an even layer/film like it does on the sidewalk? No. The surface is hydrophobic, meaning it repels water. The hydrophobic nature of the wax combined with the surface tension of the water combines to form obvious beads of water.

What does this have to do with your question of how overlapping membranes joined with porous mortar are sealed from moisture intrusion? When hydrophobic membranes are overlapped to each other and the physical proximity is close enough that the surface tension overcomes the capillary action, moisture cannot penetrate. In short, the surface tension of the membranes repels water from the otherwise porous seams, making them waterproof.

[MisterJJ]

As an engineer, I had a hard time accepting this as well. I have yet to hear a good scientific explanation but decided to just accept the evidence that it works. I think the key is that normal capillary action requires a certain amount of space to work and having the membrane in close contact prevents this.

With this in mind, I got really compulsive about using pretty thin thin-set, and squeezing most of it out as I went. Originally, I was going to fold the base membrane up under the wall membrane but decided that was too difficult so I went the easy route of doing the walls and floors separately and then just using the band to join them. I did my flood test for 50 hours... no problem.

[Shady at Best]

Is there a fine line between squeezing too much thinset out vs leaving enough in between the kerdi band and overlaps?

I think of taping drywall but not sure if the 2 should be compared. The drywall tape isn't going to stick if you squeegy all the joint compound out.

Back to kerdi. I really like how well customs versabond adheres to kerdi. It will strip all the felt off after a few days of dry time. I also like using thinset with fine sand.
I very much dislike Schluters new schluter set thin set. Its got huge grains of sand in it. Its like trowling over ball bearings.

Travis, that is a very good idea!

[Tool Guy - Kg]

Yes, you can squeeze too much out. If you’re applying firm pressure, limit striking the joints to no more than two times with the taping knives.

[Melanie's Eden]

Thank you for all your replies. I also have an engineers mind so I have been told, glad I am not the only one who had these thoughts. I am just [as I knew I would] trust that it would work. Thanks again