Tub Surround Installation Question

[zaphod]

Hi Everyone,

I'm working on a tub surround and I've been searching and searching, but I can't seem to find the answers to a few simple questions.

Here is what I am doing: It's a simple tile surround above a whirlpool bathtub. I have installed Perma Base down to the tub flange, but not covering it, directly onto the studs, with no vapor barrier behind it. I now plan to install Kerdi Membrane on the surface of the Perma Base, the Kerdi will overhang down over the tub flange, and then I will install the tiles onto that.

My question is: With a Kerdi membrane installation, do I still use the fiberglass mesh tape on all the joints? and if so, is this installed in 2 separate installations? In other words, do I install mesh tape on the seams and corners with thinset, then install the kerdi with more thinset? or just put the mesh tape in the thinset used to hold ther kerdi on.. or do I even use the mesh tape if I will be using Kerdi?

One thing I did find out from reading through things is that I don't want to create any humps in the wall, so thats what got me thinking, of perhaps doing both the mesh tape and kerdi at the same time, because then I won't end up with thinset on top of more thinset.

any advice would be greatly appreciated.

[Houston Remodeler]

Zaphod,

Welcome to the forum.

1- no need to with kerdi
2- See #1
3- See #2
4- See #3
5- See #4

[Richard Tunison]

You are quick tonight Paul1.

I'll go play some golf...........

[zaphod]

I wasn't too sure about #3, but #5 answered my question nicely LOL. Thanks for the fast response Paul1

That sure simplifies things. Ok, next question:
See the hopefully attached photo... the walls behind the tub seem pretty straight forward, but what do I do with my strangely shaped corner shelf thing? I am guessing I will need to cover it with Kerdi in sections: starting at the bottom and working my way up, and overlapping the kerdi. How much of an overlap do I want and is this overlapping going to cause any issues with the tiles or is the kerdi thin enough that it won't hurt anything?
and while I'm getting educated on the subject.... do I want to wait for each section of kerdi to dry before installing the next, or do I just keep going, and install more on top while it's still wet?

Sorry if this seems extremely basic, but I am a complete novice when it comes to tiles

[Houston Remodeler]

0- Remember what I said about numbering your questions ?

1,2, & the rest of them - As long as you maintain a 2" overlap you fine. Buildup reduction takes practice and forethought. Sometimes we compensate for buildup by building benches smaller and niches larger. You can do all the kerdi then start tiling immediately. No need to wait between pieces of kerdi or kerdi and tile. Pretty cool huh?

Ceement board is very thirsty. You'll have a much easier time if you thin down some Red Guard 1: 4 with water and apply that over the CBU before starting the kerdi.

Watch this video to see how thin the thinset gets mixed.

[zaphod]

Yes, Very Cool!! Thanks again for the help and advice. I'll go watch the video.

[zaphod]

Question #7: Should I attempt to cover the 3 walls with one piece of Kerdi? The sizes are 34x22 66x22 18x22

[Houston Remodeler]

It's been my habit to run one piece of Kerdi horizontal all the way around hung to a height of 33" to allow for a healthy overlap on the floor. This will help eliminate some of the more troubling wall build up. The floor build up is easier to handle. Plus you can tile the floor after tiling the walls and still have plenty of area to overlap the floor Kerdi.

Somewhat carefully typed on teensy cell phone keys.

[zaphod]

One piece sounds like the way to go.

8) would it be best to install it in sections, perhaps apply thinset to one wall and around one corner, install it that far, then thinset the majority of the long wall, install it to that point, then thinset the remainder and finish the installation, OR just apply thinset to the whole thing and install it all at once? total size is just under 10 feet x 2 feet

[Lakee911]

If your thinset is going to start skinning over (i.e., drying), before you can get it covered, than work in sections.

[zaphod]

I got my Permabase coated with a 1:4 dilution of Red Guard. I think it came out pretty well. Now that I know that little trick to keep my thinset from drying out too quickly, I think it would be much easier if I coated my permabase outside on a pair of saw horses before I screw it to the wall. I ended up making a pretty big mess because it's so thin it just wanted to run down the vertical sheets, but I kept rolling it around until the sheets were coated with it. Unfortunately it did run underneath my making tape and onto my tub surface, as the masking tape didn't really stick to the fiberglass all that great, but it all cleaned up nicely.

9) what's the best way to keep the thinset off my fiberglass tub while I'm installing the kerdi membrane?

[zaphod]

I'm getting ready to install the Kerdi membrane on my tub surround.

10) What kind of mortar do I want for this? There are So many kinds and the people at my local stores just don't know, they don't even know what Kerdi membrane is, since they don't sell it, I had to special order it in. There are so many kinds of mortars all labeled as 'Thinset' I'm really confused here.

Here is what I have:
http://www.lowes.com/pd_13485-1295-1...tar&facetInfo=

I'm wondering if I need something more like this:
http://www.homedepot.com/p/Custom-Bu...BW40/100183448

Any advice would be greatly appreciated, I have zero experience with this.

[zaphod]

Perhaps this is what I need?
http://www.lowes.com/pd_12639-1295-1...tar&facetInfo=

[Richard Tunison]

That is the proper thin set to use with Kerdi.

[Richard Tunison]

Just realized we are close. I used to live on Oak st. by the High School.