I am just finishing up my Schluter shower. The last step is to hook up the drain. The Schluter drain is 2 inches and the original house drain is 1-½ inches. The original drain/vent is copper and is connected to a cast iron main.
I would rather not mess with the connection of the copper drain/vent to the cast iron because they are both original to the house and are over 60 years old.
Is reducing the pipe size by ½ inch all right or do I need to have a 2-inch drain all the way to the main.
Thank you in advance for you comments.
Replies
My main concern with a modern shower in an older drain fixture is the ability to pass hair without clogging. I have a screen in my shower drain, and you wouldn't believe the hair it catches. Same with the clothes washer and drainage lint. I believe that most home owners are thinking of other, more pleasurable stuff when they install these things and aren't practical about the potential down stream consequences. If you can clean it out periodically, then maybe okay.
It depends a lot on what the copper is doing. If it's a long run with barely enough slope then you should replace it. If it's short and steep then not so much.
In either case, maybe you can cut out the copper up to where it mates with the cast iron, leaving a few inches of copper in place. Replace what you cut out with 2" plastic and then use a 2" x 1-1/2" Fernco coupling to join plastic to copper. That way you have as much 2" as possible without doing the whole thing.
If you can lay hands on a cast iron snap cutter it's a piece of cake to cut out the CI fitting that receives the copper and replace with plastic, then glue plastic all the way from the Kerdi drain.
is the waste vented? you may have bigger prolems then size.
your shower drain line should be 2" ...
a tub is 1 1/2.
putting in the right size drain line should have been the first step.
no permit , no plumber and not inspected I see.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Building code in my area calls for 2" drain for tubs and showers. The existing 1-1/2" may be acceptable because the grandfather clause, I'm not sure.
Changing the connection to the main DWV to 2" won't be easy, especially if it's cast iron. Simply connecting 2" pvc to a bit of the existing 1-1/2" doesn't do anything but create a bottleneck affect.
Personally, I'd make it 2" all the way, but just using a reducer to the existing 1-1/2" might be acceptable. ~ Ted W ~
Cheap Tools! - MyToolbox.netMeet me at House & Builder!
You will be sorry if you don't replace it all the way 2", unless all users of the shower are bald.
Most times if it is a lead caulk conection to the cast it is 2" then reduced to 1½. A tapped conection could be either. If you have to replace the cast wye use a grinder to cut out the old one, a chain snapper on 60 yr old pipe has a chance of crushing it and is jarring enough that it will loosen up scale on the inside, possibly causing other clogging.
If this all sounds to daunting, I would spend a few sheckles on a plumber rather than leaving the 1½.
I own a Ridgid snap cutter and have used it many times without crushing the pipe, which is always old. Never tried a grinder, but have tried a sawzall... which caused me to buy the snapper.
Thank you everyone for your input.
If the transition from 2" to 1-1/2" is in the vertical, that is, on the tailpiece above the p-trap, and if you make that transition with a bell reducer/increaser (as opposed to a bushing, because the bell reducer will have a sloped transition, not a square one), then you probably can get by just fine. I say this as a one-time plumber (27 years), and as a plumbing inspector for the last 16 years.
No, it would not meet the letter of the code, but it would work in the configuration I've described.
As others have noted, most codes require 2" for showers, but the ironic thing is, a shower that is part of a tub/shower combination is allowed to have an 1-1/2" drain, even though the tub will discharge a sudden, large volume of water compared to the relatively small flow the shower will generate. Especially with today's 2-1/2 gallon per minute shower heads, an 1-1/2" pipe will easily carry the flow, and, in fact, will give a better scouring action than 2" pipe in such low-flow conditions.
Unfortunately, plumbing codes have been slow to catch up with the reduced flows of modern fixtures. The sizing charts in plumbing codes were based on research done in the 1920's by David Hunter, back when showers ran at 5-7 gallons/min., and toilets flushed with 7-1/2 gallons per flush.
The mixture of hair and soap curd will always be a problem in any bathroom sink or shower or tub, even those sized larger as others have pointed out. You can help reduce the problem by not using bar soap, which has a high content of fat in its composition, and by pleading with family members to wipe hair out of the fixture as much as possible, instead of sending it down the drain. Good luck!