Bath P-Trap Pipe Options

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gth1

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Hello,
I'm replacing a pedestal sink in my bathroom and want to replace the waste pipe/p-trap as well (the house is 70 yrs old). The old sink had an unsightly combination of pipes, bends and adapters leading to a massive 1.25 inch MPT connection just under the floor level. I'll try to attach photos of the old pipe combination and an example the simpler connection I'd prefer to install. I haven't seen any obvious plumbing solutions at the local hardware store that would allow easy threading into the 1.25 inch MPT outlet in the floor. Any suggestions?

Cheers, GTH

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Cacher_Chick

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Problem #1 is that you have an S-trap, which is no longer permitted by code. To meet the current requirements, the trap will need to be vented. Proper remodel would be to install a drain and vent stack into the wall framing so that a proper horizontal trap arm can be installed into a sanitary tee in the wall.
If you are not doing a remodel, you should find out if your plumbing code will allow the use of an air admittance valve. Unless you are installing a vanity, you are still going to have the pipes showing under the sink.
 

Gary Swart

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Even if an AAV is legal, it will be unsightly because it would have to be under the sink. As Cacher_chick pointed out, you need to go into the wall with a drain and vent stack. You can't hide an AAV in the wall, you have to have access to them since they are mechanical devices and can fail. I don't know of an easy, cheap way to do this.
 

Jimbo

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I do not agree that it is helpful to recommend opening up the wall and the roof to try to make this 70 year old bathroom conform to current code. Yes, you will have to be careful to keep the S-trap full of water.

The arrangement you have is about as simple as it will get. I can't see dimensions, but you talk about 1 1/4" below the floor, so I suppose that is a 1 1/2 to 1 1/4 reducer coupling in the photo. No way to get around that. And the extra 90 is to make everything line up. Depending on the new sink or vanity, you will have to use similar to make it all line up. You can get chrome plated fittings to look better.
 

Dlarrivee

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I do not agree that it is helpful to recommend opening up the wall and the roof to try to make this 70 year old bathroom conform to current code.

Why not? Doing it right is always more work isn't it...
 

Jimbo

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He's just replacing the sink. I don't think we are going to go into every home in America that happens to have old plumbing, and make them spend serious bucks to "fix it up". If he was remodeling the bathroom, that's different. This is not that
 

Dlarrivee

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So it costs "serious bucks" to install 20-30' of pipe, a couple of fittings?
 

Gary Swart

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I think you have to realize that it would require open the wall, moving the drain, installing a vent, then closing and refinishing the wall. Guess it depend on what you call "serious bucks". That is what would have to be done to eliminate the S trap and make it right. Would it be worth it? Seems that it has been working OK for 70 years, so you decide if it would be worth the expense.
 

Dlarrivee

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Gee thanks for the explanation.

Nobody in their right mind buys or owns a 70 year old house and expects to be frugal about the inner workings of the home, do they? In the end you get what you pay for.
 

Basement_Lurker

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s-traps are illegal, that's all there is to it.

owning a home is expensive, and dlarrivee is correct that you should do something right or not do it at all. perhaps the wet wall can be accessed from behind, meaning for a least destructive addition of a vent stack.
 

Cacher_Chick

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Had he left it alone, most places would "grandfather" it and then no correction would be needed.
Now that it has been removed, the only proper repair is to bring it up to current code.

All the better reason to know what one is getting into before starting the job.
 

Dlarrivee

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Had he left it alone, most places would "grandfather" it and then no correction would be needed.
Now that it has been removed, the only proper repair is to bring it up to current code.

The legalities of it being left aside, I would personally prefer to remove an S-trap from the home, if it were mine.

Owning a home comes with expense, owning an older home comes with expense that most folks don't think about.
 

hj

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Starting with the fact that the drain is an "illegal S trap, and has a "reduction in size" in the direction of flow, then the two elbows are NOT drain fittings, they are the cast brass outlet elbows for sink traps, there is not much about the old drain to recommend it or emmulate with the new one. The drain can be reassembled using a 1 1/4" "S" trap, if you can find one, but you will find that it will PROBABLY gurgle after every usage, regardless of how it has worked for the past 70 years.
 

gth1

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All -

Thanks for all the replies and I much appreciate the concientious concerns regarding a more in-depth retrofit. I've enjoyed my old house for 17 years and have made my peace with it's dated configurations and quirky modifications made by previous owners. As Jimbo pointed out, the goal is to replace one pedestal sink with another -- I do not plan to rip up flooring, drywall or roof to do so, although I understand why others recommend it. New S-traps appear to be readily available for less than $20. I'll try to make that work. Thanks again!
 

Dlarrivee

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Even with lots of great advice, he's still going to do the typical home-owner repair... Jimbo must be proud.
 

Dlarrivee

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Another case of asking for advice, and then doing EXACTLY what he planned to do in the first place.

I'm glad you mentioned the fact that the drain reduces in size as it goes down stream... I'd be even more concerned about that than the S-trap.
 

Gary Swart

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Just another case of someone wanting approval for doing what he wants to do even if it's wrong.
 
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