How much should the water level drop in a Kerdi Shower flood test?

**boardable** · 09-29-2012, 09:00 PM

Very true. I do agree. I am going to use bostik epoxy grout. Any good ?

**johnfrwhipple** · 09-30-2012, 07:15 AM

Originally Posted by jadnashua

...This is the one big advantage of a surface membrane, however achieved: the water stops at that point and doesn't saturate the substrate. ....

Jim a tile floor will stay saturated. As Boardable found out the thinset moves moisture around especially where it is in contact with Kerdi. So a poorly prepared seam could potential wick water through it forever.

That said the flood test shows us that the shower under "Worst Case" Scenerio holds tight. This is whyy we flood them for three days to be sure.

An Evaporation control is another dish or pan with water in it. Measured the same way. A small coffee cup will evaporate at the same rate as coffee can full of water. A bread loaf pan the same rate as the shower. I have a little fishing tool box I use now as the control.

JW

**boardable** · 10-01-2012, 12:05 AM

I agree flood test is a mandatory thing. Membrane will always stay wet. Even if a little water gets there. How do you guys feel about urethane and epoxy grouts ?

**johnfrwhipple** · 10-01-2012, 06:23 AM

I was talked into using a urethane grout on my kitchen counters. I wish I had not.

When it comes to grout selection I would be leaning to a light gray or white colour. Nothing else.

JW

**jadnashua** · 10-01-2012, 07:05 AM

While costly, and if you like the look, epoxy based grouts should be a lifetime install without regular maintenance. You can get some special effects with them (glow in black light, for example or glitter), if that's something that may go with the install design. Some are harder to install on the vertical than others (because it can slump a little), and cleanup is critical (but regular grout needs good cleanup, too) as it's harder to clean again afterwards if you miss some. Epoxy grouts have improved over the years to become easier to install and their colors will be brighter than any cement based grout.

**boardable** · 10-04-2012, 08:13 AM

I installed a euro thane or epoxy. Can't remember which it was in my parents shower. It was cleaner but yes the film was annoying took me a good 4 hours with caulking in the corners. Not sure. But with epoxy or eurothane grouts is it still necessary to caulk the corners ? Or is the grout just fine ?

**jadnashua** · 10-04-2012, 09:08 AM

Industry standards call for caulk at the changes of plane (corners, floor/wall joints, etc.). Urethane remains somewhat flexible, so you could likely use it everywhere...epoxy does not. You likely used epoxy as, in a wear surface, it's harder and stronger. Epoxy would remain easier to clean as it is a very smooth surface. Abrasion can rough up urethane.

**johnfrwhipple** · 10-05-2012, 06:55 AM

If you are in a rush and need to flood test your Kerdi Shower sooner than later you could consider using Ardex's 8+9 as a seaming material. Like how Kerdi is installed overseas this approach can allow you to install your Kerdi and flood test the same day.

I have never tried seaming a topical membrane like Kerdi with a cementious product until last week.

This has been holding water for days and was made with Noble Company's Noble Seal SIS and Ardex's 8+9. I cut a large hole in the bottom.

I'm going to test the 4 hour window very soon but product information states just this. I have found that the 8+9 product dries a little slower than printed instructions so to be safe I would still wait till the next day to flood test any shower using this approach.

JW