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View Full Version : How to run the drain pipes? Is 90 degree OK?


fcandreasson
Jul 18, 2007, 12:22 PM
I'm in the process of replacing some galvanized pipe with PVC, but I'm unsure of the best way to run the drain.

A shower drain of 1 1/2" galvanized pipe runs with a couple of smaller 1/8 bends and then makes a 90 degree bend before a vertical sink drain of 1 1/4" pipe is connected to this line , which then runs about 4 feet before it connects to the main stack.

I have replaced the 1 1/4" sink drain with a 1 1/2" PVC and I now need to connect the shower drain and the vertical sink drain.

Is it OK to "remove" the 1/8 bends and just run a straight 1 1/2" PVC then make it turn 90 degrees as the sink drain is connected?
Not sure if a 90 degree turn is too much because the sink drain is in the same spot. The drain is horizontal with a slope of probably 1/4" per foot.

A drawing is attached.
By the way, I cannot replace all of the galvanized pipe due to space issues.

Thanks!

iamgrowler
Jul 18, 2007, 05:06 PM
If you're going to all this trouble, you should consider upgrading the size of the drain line to conform with modern Plumbing codes.

The shower drain, trap and trap-arm should definitely be upgraded to 2" -- And you'll have fewer problems down the line if you upgrade the lavatory drain to 2" as well.

As for eliminating the combo that makes up the clean-out, if it's accessible, you should install a new clean-out at the end of the run, if it isn't accessible, you should pick up the shower first and the lavatory last, and then install a clean-out tee just under the sanitary tee of the lavatories p-trap.

Trust me, if upgrading/upsizing the line is an option, you'll be very happy you did so.

fcandreasson
Jul 19, 2007, 08:50 AM
If you're going to all this trouble, you should consider upgrading the size of the drain line to conform with modern Plumbing codes.

The shower drain, trap and trap-arm should definitely be upgraded to 2" -- And you'll have fewer problems down the line if you upgrade the lavatory drain to 2" as well.

As for eliminating the combo that makes up the clean-out, if it's accessible, you should install a new clean-out at the end of the run, if it isn't accessible, you should pick up the shower first and the lavatory last, and then install a clean-out tee just under the sanitary tee of the lavatories p-trap.

Trust me, if upgrading/upsizing the line is an option, you'll be very happy you did so.

The problem is that I cannot access the entire drain from the tub-shower.
Would it make sense to replace what I can with 2" and leave the rest as 1 1/2"?
I looked at bath drains (the plug and immediate drain from the tub) and they all seem to be 1 1/2". How would I connect such a drain to a 2" P-trap?

I am planning on installing a cleanout just below the sinks and also where the existing clean out is.

Thanks again!

iamgrowler
Jul 19, 2007, 03:44 PM
The problem is that I cannot access the entire drain from the tub-shower.
Would it make sense to replace what I can with 2" and leave the rest as 1 1/2"?
I looked at bath drains (the plug and immediate drain from the tub) and they all seem to be 1 1/2". How would I connect such a drain to a 2" P-trap?


You didn't specify it was a tub/shower in your first post, so I assumed it was a shower only.

You are correct, an 1-1/2" trap for a tub or tub/shower is the norm.

If the line going into the stack is one of the inaccessible parts you mention, then just leave it all as 1-1/2" -- Telescoping on the downstream end is the last thing you want to do.


I am planning on installing a cleanout just below the sinks and also where the existing clean out is.

Technically you don't need the clean-out on the lavatory if you have a line clean-out, but if you have room to do so, then go for it.

fcandreasson
Jul 19, 2007, 04:51 PM
Thanks!
I'm sticking with the 1 1/2" then.

Interesting to me that a shower requires a larger drain than a tub... I don't really get the logic behind that... but obviously I'm not a pro :)

Thanks again! All help is highly appreciated!