View Full Version : Remodel Bath to Shower

02-03-2008, 08:30 PM
Hello, my first post. I am an amateur remodeler.

I have removed a tub on my second floor bathroom and plan to install a tiled shower in the 60" x 30" tub footprint keeping to the original drain location (10" from left side of tub) because of a large beam that blocks the center area of the old tub. I plan to use a membrane on a built up sloped mud base. I do have access to the drain plumbing from above via a 12" square hole in the floor, and access from below could be gained by taking out a section of ceiling in a first floor closet area

Examining the existing drain plumbing I found 1-1/2" copper DWV pipe for drain water branching to a main copper drain (I have no easy access to that connection without ripping out first floor bath ceiling) and copper for vent pipe. I had no issues with drainage/clogs with this drain.

My issue is how to connect the copper DWV pipe to the ABS drain. I am concerned because:

a) the drains I have seen are ABS and seem to be sized for 2" or 3" ABS pipe. How to I connect the 1-1/2" DWV copper to the ABS? Can I use ABS adapter to get from 2" to 1-1/2" and then use some king of adapter to mate the ABS to copper? Should this be a threaded connection or can I use a flexible coupling such as Fernco/Proflex (spelling??).

b) Is is OK to reduce the shower drain from 2" ABS to 1-1/2" ABS and then to the existing 1-1/2" copper DWV or will this cause problems?

Thanks in advance for your advice.

02-04-2008, 05:21 AM
You haven't had issues with the tub draining into the 1 1/2" pipe because it holds the water and then it drains as fast as it can. With a shower, you may have a problem because it's water has to drain as fast as the faucet is running, which could be in excess of what the 1 1/2" drain can accomodate. There are transition compression couplings to mate the two materials, but going from copper to ABS and then increasing will not improve the drainage, so you might as well continue the 1 1/2" all the way to the shower drain fitting and reduce it at that point to 1 1/2" to eliminate any potential problems where the reduction in size occurs.

02-04-2008, 10:02 AM
Thanks for the timely reply and advice. I will use a compression fitting to mate and will use 1 1/2" all the way to the drain where I will put in a 2" to 1-1/2" reducer.

As I recall from showering in the tub, the drain handled the flow, except when hair plugged the screen at the top. Interestingly, the shower drains I have seen seem to have very large 'grates' instead of fine screens and so I would think they would pass most hair along, and it might get clogged further along if there was a buildup of soap, etc along the drain pipe. When I pulled the old p-trap there was quite a bit of hair in there.

Thanks again, Larry the Amateur

02-04-2008, 03:46 PM
If you are going to get this permitted and inspected, the inspector may make you replace the 1.5" line all the way back to the stack with a 2" one. Then, it won't be a problem. You want the trap right under the drain, or you'll end up with a lot of pipe that can get stinky with hair or soap scum.

Schluter makes a tileable pan made for tub replacements with the drain at the end. It is designed to work with their Kerdi shower system www.schluter.com (http://www.schluter.com). A drypack shower pan would be less expensive, but the pan might be quicker, if that is an issue. Given a choice, I'd use Kerdi, regardless of the type of pan used. You'd need their drain, though which comes in either ABS or PVC depending on your choice. The drain comes in various finishes, and is square, which often makes it easier to get the tile to. In the one I did for my mother, she chose 2" tiles, I just took 4 out of the sheet, and it fit right over the drain perfectly with no cutting at all! In fact, other than cutting off some tile from the sheet, I did not have to cut any of the tile for that pan as it is exact the sheets fit in great.

02-08-2008, 11:39 AM
Much thanks. I ordered the Kerdi shower tray, drain and membrane material as you recommend. I will be able to locate the trap right under the drain, and am considering running 2" all the way to the main stack, but it will require ripping out some of the ceiling in the first floor bath that was remodeled last year, not a pleasant thought when added to the prospect of replacing the large copper fitting in the stack, a job I think best left to a pro.

02-08-2008, 04:15 PM
Everyone that used the Kerdi system was happy that I know of. The best place for help while doing it is www.johnbridge.com (http://www.johnbridge.com). John has written a couple of books specifically on how to use that stuff and it may be a very good investment (only about $10 as an e-book).

02-14-2008, 05:21 PM
Thanks, got the book and it is great. The DVD that comes with the Kerdi drain is also very good. It expands on the small videos that are on the Schluter web site. I have installed the Kerdi drain, and tray and will be laying in the membrane soon. I went ahead and tied the Kerdi drain (2") to the existing 1-1/2" drain line using a flex coupling. Tested it with a ton of water poured down the drain and it flows well and is water tight.

Thanks for all the advice and assistance.