Copper Shower Pan Vs. Rubber Membrane

[emptysea]

Could someone please tell me the plusses and minusses of using a Copper Pan vs. a Rubber Membrane system? My Plumber wants to do a copper pan, and has no faith in the rubber membrane system. He won't even install it. The Tileman wants to use a rubber membrane and a mud floor. I asked if him it was Kerdi, but he said he uses another brand that is thicker. He didn't tell me the manufacturer or what process he uses though. The shower will be around
30" x 60". I've done some research, and the only difference I have come up with so far is the cost. The copper shower pan seems to be more expensive. What are the other differences, and which do you think is 'better'. Thanks. Michelle

[Splinter]

It seems that there arent too many plumbers who will take the time to prep a shower floor properly... There's more to it than just clamping a pan liner to a drain pipe. This is why most tile guys here like to do it themselves.... A shower requires a preslope. This is a mortar bed BENEATH the liner which directs any water to the weep holes in the drain. I'll guarantee your plumber has no intention of laying a preslope before installing a copper pan... It would be quite difficult to get the copper to conform to the preslope anyway... Also, I doubt the plumber will notch the studs and add proper blocking so the backerboard fits straight and secure.

Let the plumber set the drain, and leave the liner to the tile man... Copper pans are rarely used anymore... Seems its a northeast thing...

Edit: just out of curiousity, why does the plumber have no faith in the PVC liner? I'm guessing he's been doing copper pans for 30 years, and NEVER had a problem... right? ugh!

[emptysea]

You're right Splinter, I am in the Northeast, in MA. The plumber said "it's a rubber membrane, it could tear, if it tears that's it" and "it's not a plumbing thing, if it leaks it leaks, it's not my responsibility". He's a young plumber, but he only uses copper pans. I think it's just the thing here that's all. Thanks.

[Davy]

I think the PVC liner has more advantages than the copper. Like Splinter mentioned, all liners need a preslope, the PVC will form to it better. The PVC liner can be patched if you knock a hole in it, not a big deal.

Your plumber only knows copper pans, that's all he's going to recommend. Let the tileman do the pan but make sure he puts down a preslope, we are re-training plumbers as well as some tilemen.

[Splinter]

Check out the shower constuction thread in the liberry for some great info... PVC, CPE liners are basically the norm for shower construction these days... Liners arent subjected to wear, since they're sandwiched between two mortar beds. The only chance of damaging it is during installation. (It's easily repairable as well)

There may be something in the Massachusetts codebook that requires copper pans still, but I'd rather argue with the inspector about my PVC liner than install a copper pan without a preslope.

(I dont build showers too often, but when I do, I use KERDI now.... )

[Splinter]

Hmmmm... y'know, I picked "Splinter" as a handle 'cause I'm a finish carpenter at heart, but y'all can call me Alex...

Maybe one of the world famous JB moderators can change that little "registered user" tag to "Call me Alex"

[emptysea]

Thanks Davy and Alex I didn't think about the preslope, and doing all the prep work. I don't know that the plumber wouldn't do it, but I don't want to ask and aggravate him either, *lol*. I told him we're going to go with the rubber membrane, and he said okay. He just wanted to know how high for the drain so he can glue it, and I told him not to glue it until the tileman does his thing. So, everything seems to be going well.

Up until 2 days ago I thought I was putting back another bathtub, then we decided to go with the shower last minute. (I still have the tub sitting in my living room) I haven't had much time to prepare, so this forum is extra handy today. Thank You.

Oh, and the Plumber said that both are code in MA.

[Davy]

Is the plumber going to move the drain to the middle? Sure will look better and help the tileman.

The bottom flange on the drain needs to be about 1/4-1/2 inch above the slab. This will give you a little mud at the drain for the preslope.

I don't know how long a copper pan will last, I'll bet not as long as a PVC.

[emptysea]

Davy, Today the plumber was able to move the drain to the center. He replaced the drain pipe and the vent with PVC pipe. Luckily the joists ran the right way, and he did not have to drill through any of them.
I don't have slab, I have 16" apart joists and 1 x 8 ledger board or something on top of that. I plan on putting 1/2"-5/8ths exterior grade plywood on top of the ledger board, and then a 1/4" cement board.

[Davy]

Okay, thought you had a slab for some reason. Skip the 1/4 inch cement board. Put down tar paper and wire lath before putting down a preslope. How high did the plumber set the bottom flange of the drain?

[emptysea]

Hi Davy, I forgot that what we do under the rest of the bathroom is not what we do under the shower, so no cement board. Thanks for reminding me. Ultimately, it will be up to the Tileman. I am not sure how high the bottom flange is, he is still working in there.

[Davy]

You might ask and see, I know you don't want to pry, but it's good to know. The bottom flange needs to be 1/2-3/4 above the plywood height.

[emptysea]

If the bottom flange is the round thingie at the bottom of the drain, that's what he hasn't glued in yet. It comes out.

[Davy]

The height of the riser pipe under the drain will control the height of the drain. If it's too low, the drain will be too low or vice versa. The drain height can vary a little and still work but I wouldn't want it too low for sure.

[emptysea]

He's welding the shower stuff right now, so I can't get in there. I think the whole drain system he put in comes out, and he also showed me earlier that it is adjustable too, because the top part screws up and down. He said earlier he'll come back and put it at the height the tileman needs. I wish I could save him the trip, but I want the tileman to decide.