Kerdi Band question

[tweeks]

My first post (well actually I responded to someone asking network related questions) so I guess this counts as my first question. But before I get to that I have to say that I have learned an amazing amount just browsing this site. My wife and I are constantly researching stuff on the web and this by far is the most valuable site I have ever run across. Great job!

Now to my question. Putting in a new master bath and am going to use Ditra on the floors and Kerdi in the shower. Never used it before and am a bit hesitant but we are into our 3rd remodel and I am always up for something new! The Kerdi Band comes in 3 widths (5", 7.25" and 10") and wondering if anyone has found one of these easier to work with. I know I have to overlap 2" on the floor and walls, so the 5" doesn't give much margin for error. 7.25 would seem to be wide enough and easier to work with than the 10". Anyone have any thoughts?

[Bri]

Hi
I'm not sure what you are going to do with the kerdi-band? The 2 inch overlap on the kerdi is enough to waterproof the shower, and on the ditra, the five inch is lots to use on the seams...though it's not needed at all unless you are planning to completly seal the bath floor.

[Cisco]

welcome tweeks,

You dont need the kerdi band to waterproof the shower you just over lap the kerdi seams by at least 2". If your looking to waterproof your floor just cut strips from the kerdi matting to waterproof the seams and wall junctions. This way you dont have to buy any kerdi band. The only difference is the kerdi band is 4mil thick and the kerdi matting is 8mil. I dont think 4mil is going to cause any problems.


Cisco...

[John Bridge]

Hi Tweeks, Welcome. Please give us a first name.

While I agree that overlapping the Kerdi in the shower will work, the reason that the Kerdiband is thinner is so there won't be as much of a buildup at the joints. That, and the band is easier to work with in the angles. Typically, a piece of Kerdi goes on the shower floor, then the angles are done with the band, allowing the band to travel up the wall a couple inches. Then when you install the Kerdi to the walls, you allow it to hang down over the band and cement it there with thin set.

The thin set used to cement the joints together should be mixed almost runny. Not watery, but very loose.

Once again, simply overlapping the pieces of Kerdi will work. I'm not trying to argue. I'm merely pointing out that there is a definite reason for the Kerdiband.

Unless you want to waterproof the floor, you simply butt the pieces of Ditra together and tile away. If you do want to waterproof, use the 5 in. Kerdi band.

[tweeks]

First name Tom, and thanks all for your replies. Not looking to waterproof the floor at all, just want to use the Ditra to keep from having to use backer board over the plywood. I am embedding an electric floor heating system underneath (Warmly Yours), so wanted to eliminate the buildup of all those layers. Plus it's a large bathroom and it keeps from having to haul a bunch of backerboard up 2 flights of stairs (i know i am a wuss). And since I live in an earthquake zone in San Francisco, I am heavily speculating that by putting in an isolation membrane I can help eliminate cracks from minor earthquakes.

John, I was thinking with you that the 4 mil of the Kerdi Band made it a bit easier to use in the corners of the shower which is why I was going to try it instead of overlapping the 8 mil Kerdi from the walls onto the floor. Sounds from the replies that the 8 mil Kerdi is easy enough to work with in the corner, and it would certainly be beneficial to eliminate another seam. May be the way I end up going.

I also have a seat in the shower which is simply the extension of the tub deck. Piece of glass will separate the shower from the tub. From many threads on this site sounds like I just need to slope the portion of the deck that is in the tub (i'll actually slope the substrate), and make sure the Kerdi runs a bit over on the tub side of the glass. The tub deck probably doesn't need waterproofing (or the walls adjacent to the tub) but I might just Kerdi the whole thing for the hell of it.

Thanks again everyone.

[K_Tile]

When you purchase the drain it will come with a couple of Kerdi-Kereck sheets. Play w/ them before you buy the the Kerdi band.