Thank you to all the plumbing professionals who offer their advice and expertise
Welcome to Plbg.com

Over 540,000 Posts in over 160k Threads

Welcome to Plbg.com (aka: PlumbingForum.com) we are the most popular plumbing information sharing, advice, DIY and educational forum on the Web. Ask any toilet, sink, faucet, pump, water quality, and plumbing related questions. Please refrain from asking where to purchase a product, business, pricing, or legal questions, for contractor referrals, or any questions not related to plumbing. Keep all positive and no advertising. Our largest sponsor and best online plumbing supplier is: Buy plumbing supplies online 

Post New
Search
Log In
How to Show Images
Newest Subjects
 shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: turnerover32 (Non-US)

Hi


I have a few questions about replacing an existing bathtub with a shower as we remodel our bathroom,

The existing tub on our upper floor was plumbed with a 1.5 inch p-trap and then a horizontal run of about 9 feet before it heads vertically downwards towards the basement between all the walls. My understanding is that code calls for 2 inch drain pipe for a shower. My question is somewhere along the line (I can rip up the subfloor) I need to transition form the new 2 inch drain to the 1.5 inch line and what would be the best place to place this reducer to minimize the speed at which water can flow. It could be right at point the drain meets the the p-trap where I could reduce to 1.5 inch p-trap or I could put in a 2 inch p-trap and 2 inch line and then transition at the point the horizontal drain line connects to the 1.5 inch vertical drain line between the walls headed to the basement. I am thinking the second option would be better?


My second question I son venting- the existing tub never drained very fast. The current vent is about 52 inches form the existing p-trap. I have looked at code on the web and it varies by jurisdiction with it being with 5 feet in some and within 3.5 feet. My question is if I move the vent closer than the existing 52 inches could I increase the rate at which the water drains. If I actually left the first vent in place and added a second vent that was closer could this cause a problem?

Any advice would be appreciated

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

Vents do NOT help drainage. They have a specific purposes in the drain system but that is not one of them. I could tell you that drains may work better without a vent, but that might encourage you to eliminate it, which would cause other problems. Using that 1 1/2" drain may NEVER produce a shower drain which is acceptable, regardless of where you make the reduction in size, (that reduction in size in the direction of flow also being prohibited by EVERY plumbing code and good practice requirement).

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: buttcrackguy (CA)

If the waste line was only ran in 1 1/2", that's what you are stuck with. If you can't find a point where the line is 2" or transitions to something bigger, then I would just install the shower drain, a 2" p-trap, and run the 2" line out as far as possible and then reduce it down to 1 1/2".

It's still going to drain, if the house is old then you just have to work with what you've got. It is what it is sometimes.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: dlh (TX)

the best thing would be to find where it becomes 2" or ties into 3" and run 2" all the way. if you choose not to run 2" all the way (without reducing it anywhere) it would be best to reduce to 1 1/2" at the drain.

- - - - - - -

PLUMBERS "Protecting The Health Of The Nation"

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

It makes not difference how far he runs the 2". At the point where it reduces to 1 1/2" and for some distance before that, the water is going to "pool" in the bottom of the pipe because he will NEVER find an eccentric reducer to keep the bottoms of the pipes lined up.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: packy (MA)

unless the reducing coupling is installed on a vertical pipe.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: dlh (TX)

such as the drain itself

- - - - - - -

PLUMBERS "Protecting The Health Of The Nation"

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

That is not what the responder suggested, if I remember correctly. He said to go a couple of feet and then reduce it.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: packy (MA)

if it needs to be reduced, reduce it at the shower drain fitting with a bushing or a nipple and coupling.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

How about figuring out how to do it correctly and not create a shower which could have an eternally bad drainage problem.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: e-plumber (NY)

That's what I've been thinking but I didn't chime in on this one...

e-plumber
-----------------------------------------------------------------------------------------------------------------------------------

"The society which scorns excellence in Plumbing as a humble activity and tolerates shoddiness in philosophy because it is an
exalted activity will have neither good Plumbing nor good philosophy: neither its pipes nor its theories will hold water." -
John William Gardner 10/8/1912 - 2/16/2002

Repair your leaking Plumbing fixtures ASAP [www.theplumber.com]
This slow drip will waste 7+ gallons of water per day.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: dlh (TX)

as long as they dont install a car wash they will probably never have a problem

- - - - - - -

PLUMBERS "Protecting The Health Of The Nation"

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

You've never heard of hair getting caught in the drain line? It will happen a lot faster, and more often, with 1 1/2".

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: mccarty.74 (OH)

Marry a bald woman.

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

As one of the plumbers said when the customer told him that she ALWAYS wore a shower cap, "Maybe she is wearing the cap on the wrong end."

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: LemonPlumber (FL)

Hj, was she Russian?Maybe French?

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: hj (AZ)

Never met her, so I cannot tell you. But he had some unique customers. One couple were nudists and would eat breakfast without any clothing. At that time the milkman still made deliveries and put the milk in the refrigerator. One day there was a replacement milk man and when he came in with the milk, he was completely flustered. Later, when they looked in the refrigerator for the milk they could not find it, so they called him to inquire about it. After thinking about it for a minuter or so, he told her, "look in the oven".

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: LemonPlumber (FL)

Nice

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: giantsfan1310 (MD)

the way to do it is put either a reducer coupling after the the shower drain or put a reducer bushing in the drain itself then tie back into trap it will work because it was an old wssc code for md and it was run like that for many years

bruce

Post Reply

 Re: shower drain transiiton 2 inch to 1 1/2 inch and venting
Author: dlh (TX)

it will work because it will. i have not seen many tubs having larger than 1 1/2" drains and they never have problems keeping up with the flow except when the drain is restricted. i am not saying they wont have to have the drain cleaned more often but in the long run that may be easier and even cheaper than trying to get the length of the pipe upgraded to 2"

- - - - - - -

PLUMBERS "Protecting The Health Of The Nation"

Post Reply





Please note:
  • Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
  • Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
  • Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
  • Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.

Search for plumbing parts on our sponsor's site:




Special thanks to our sponsor:
Buy plumbing supplies online


Copyright© 2015 Plbg.com. All Rights Reserved.