Condo building shower from scratch

[Condo]

I am replacing a 30x60 bathtub with a custom built shower. I have an issue because the drain is at the end of the 30x60 shower and I have to use a three piece “baby blue” drain which is basically a cast iron bottom(that screws onto the copper) with a plastic clamping ring for the rubber membrane. This drain is to meet fire code which means no PVC.

I have installed the drain which is about 3 inches from the end of the shower and about 2.5 inches above the slab (p trap is below the unit) it just fits but will be an inch from the tilled wall. I have built a sloping bed of sandmix which is flush to the metal flange of the drain. On top of this I put down a rubber membrane which was clamped down to the metal drain using the plastic drain ring. I installed an additional bed of sandmix on top but for some reason the slab is rocking side to side when I step side to side on the opposite end from the drain(not a lot but noticeable).

So, do I break-up the slab and retry (not sure what happened)?

Can I use the Kerdi membrane on the first slopped bed? I know I can’t use a Kerdi drain but can I fix the membrane to the metal drain flange(2 inches wide around the drain) I see that Kerdi has an adhesive. Can I use this? If not, what would I use?

[Davestone]

If the drypack was rockin i would think it would have cracked.If there was a bulge in the pan you might get some movement, but again it would crack.Is this a wood floor?That might explain some of it.I wish there was some way you could center that drain Can't help ya much on the Kerdi but i'll find someone that can.

[John Bridge]

Hi Condo. Give us a first name.

The Kerdi-drain is plastic. You said you have to have metal. I don't understand that code, but I won't argue.

To use the Kerdi-drain you'd have to get the drain trap further out into the shower floor, and you should do that no matter which method you choose.

Sounds to me like you might not have used the right kind of mortar. Did you use deck mud? There are descriptions of deck mud in the "Liberry."

[GHR]

Originally Posted by Condo

This drain is to meet fire code which means no PVC.

Where exactly are you that the fire codes are so stringent?
New York City maybe?