Hey There just signed up. In hopes to end my headache.
I've done extensive research on the Kerdi membrane.
about 2 weeks now staring at the computer.
Ok so this is what I've got.My shower was leaking found out it was the pan that was leaking. One of those ancient lead based pans.
so I've gutted out the entire shower. I have installed hardibacker
board to the walls about 9 feet high. I dont plan on tileing to the ceiling.

Any way let me paint you a picture.. The shower is rectangle
with three walls. the two side walls are are 3 ft by 8 ft.
the back wall 4 ft by 8ft and obviously the floor without the
curb is 4 ft by 3 ft. the curb will be made of three 2x4s stacked. I got a concrete floor in which I'm going to put the kerdi drain and slope the mortar to the drain.

question 1. Can I use a fernco fitting to attach my iron
drain pipe to the kerdi pvc or abs drain?

Question 2. haveing trouble or maybe just seconds guessing myself on how much kerdi membrane to get? I dont want to
over purchse Because funds are limited. I've seen places that
sell the membrane by the square foot.


thanks for your time.and as this project gets going I'll take
pictures of the progress and post.

Sounds like the shower floor is 4'x3', correct me if I'm wrong. That all comes out to 92 square feet. If you're going to have a bench, that would add slightly more. http://www.tile-experts.com offers a 108 sf roll, which would probably be as cheap or cheaper than you can get it by the square foot. That would give you a little extra if you need it (I didn't include a little extra for the curb, overlaps, and waste). They also have the drain you would need. There is a shipping cost, but no taxes, so it's pretty much the same as buying it from the store for me, plus it's delivered right to your door in about three or four days.

If you want to cut back a little, you could go up to the height of the shower head with Kerdi, which is probably a little under seven feet. That would give you a little more "breathing room" in case you have any miscuts. That's what I usually do, since no significant amount of water is going to go above that.

As for the fernco, I'm pretty sure that would work, but you might wait for a reply from one of the other guys to be sure.

Hope this helps.

Are you doing the plumbing or a plumbing contractor?

Is this a slab on grade?

There's quite a bit of prep work to do before you install a Kerdi Drain.
Do you know how to do a dry pack mud bed over concrete?

(((Are you doing the plumbing or a plumbing contractor?)))

Theres no plumbing that needs to be done. The drain pipe
is allready there from the old shower it sits maybe 1/2 an inch below the top of the concrete and the concrete is chiseled out
around the drain I would say allmost 8 inch diameter.

((Is this a slab on grade?))
Not sure if i under stand what you mean but the concrete slab does not have any grade to the drain at all.

There's quite a bit of prep work to do before you install a Kerdi Drain.

((Do you know how to do a dry pack mud bed over concrete?))

never done it before but what I was thinking, Was laying some chicken wire over the slab. and securing it down with some sort
of concrete staples. Is there such a thing? and then drypack How would you recommend Securing the chicken wire down to the concrete or is there an all together different method?

I didn't even think about just going above the shower head thanks.
that will save me some materials for the bench seat.
another question that I have Is with Kerdi membrane would I have to buy Kerdi Band to put in the wall corners and then buy
the prefabed inside and out side corner pieces for the floor
corners? Or is it all possible with just the kerdi membrane?

92 sqft thats what I figured too. just needed some reassurance.
My first home and my first big project. well its not that big
I just have never done this before. I allways say though
the only way to learn is to just do it yourself.
And thanks to this site and people like the members on here
it makes that all possible.


Thanks to everyone.
I plan on doing a lot more work to the interior of my house so I'll be around here for a long while. Hell maybe as a go, and learn more I will be able to help somebody else out with their questions.

((Do you know how to do a dry pack mud bed over concrete?))

never done it before but what I was thinking, Was laying some chicken wire over the slab. and securing it down with some sort
of concrete staples. Is there such a thing? and then drypack How would you recommend Securing the chicken wire down to the concrete or is there an all together different method?



NEVER MIND.. I just read on here you can lay some thin set on top of the concrete and then dry set over that to bond the dry set to the concrete. That would be easier.

No Kerdi-Band required ... just overlap the Kerdi membrane about 2" in all areas where the sheets meet.

Is it possible for you to post a picture of the existing drain pipe?

That 8" hole is going to have to be filled with concrete once the Fernco coupling and ABS stub pipe is attached if you leave it as is.
Unless the existing drain pipe is lowered, the bottom of the Kerdi drain flange is going to be about 4-7/8" above the existing concrete which is a lot higher than normal. This will end up making your curb really high.

This is why I asked who is doing the plumbing. You need to modify the existing drain. Do you have the skill and tools to cut that metal drain pipe down?

Something else I thought of: Is the drain pipe 2"? If not, that's probably going to be another issue.

As far as the preformed corners, you should get four inside corners and two outside corners with every drain. At least that's what I get through tile-experts. Some of the guys don't like them, but that's what I still use. When waterproofing a corner bench, I don't use any preformed corners, I just make some pieces out of Kerdi band. If the bench goes straight from wall to wall, you could use two more outside corners for the front of the bench, and two more inside corners for the back.

Good luck with that drain, sounds like a bear.

I'll get some pictures up either this afternoon or tomorrow.
for ya. thanks for the help.