Shower drain pipe placement?

[ned8675309]

An assistant plumber decided to run the pipe through the wall, rather than taking the most direct line, which would be from the shower drain to the main drain in a straight shot. When we asked the head plumber why this was done, he said he didn't know. Because we are forbidden to cut into the floor (it's an apartment), we all agreed that a 5" step-up (shower entrance platform) would be built, which would then meet up with a shower pan raised 5". A step-up, walk-in shower. see photo. We think the assistant plumber may have forgotten that the entire shower area will be a step-up platform and that maybe he thought the step-up would occur at the shower pan, which is not the case. see photo.

Our concerns:
1. The current route of the shower pipe may cause problems in the future (?) A direct route for the drain pipe would be better for the water to exit?
2. Access to these pipes will be more complicated if there are plumbing problems in the future (?)
I guess the "money" question is: Why did the plumber take the hard way and route the pipes behind the wall when he had the option to place them in a straight line to the drain?

 

[MicEd69]

There is a vent line inside the wall to properly vent the shower P-trap. If not, then you have a problem. A P-trap needs a vent before the drain line goes down vertical.

 

[ned8675309]

Yes, that could be it. These photos give some more detail ...

 

[GReynolds929]

There's no vent that I can see in the wall, where's the trap? Looks like you might be in Massachusetts, which means your code is very strict and particular about how things are done and by whom.

 

[ned8675309]

There's no vent that I can see in the wall, where's the trap? Looks like you might be in Massachusetts, which means your code is very strict and particular about how things are done and by whom.

Yeah, you're right, there isn't any vent pipe coming off the pipe in the wall. The trap is on the bottom of the shower tray, I believe (photo). Is it possible that the plumber is using a wet vent? (More than likely, he will claim that the shower is on a wet vent). Thanks for your feedback. Much appreciated.

 

[MicEd69]

A vent, wet or dry, MUST be placed such that the venting is done BEFORE the drain drops down. There MUST be an "air passage" above the water flow from the shower to the vent. And the vent MUST be within a certain distance from the trap.

 

[havasu]

This member is from Germany, where things are done very different than the Americans or Canadians.

 

[ned8675309]

Okay, that makes sense and explains a lot. Thanks again - much appreciated!

 

[TomFOhio]

Maybe Germany should be put in the location instead of numbers. I see alot that have no location listed.

 

[ned8675309]

This member is from Germany, where things are done very different than the Americans or Canadians.

Hi Havasu,
Yes, this bathroom is in Germany (I'm American) and there are some different methods and standards with plumbing. Believe it or not, cement/backer board is only recommended for pools, public showers, etc. green board is still the standard and considered A-okay for bathrooms. That said, there are similarities, as well as a good amount of corner cutting with the standards (German DINs). The German plumber appears to be competent, however, he tends to rush things a bit and get ahead of himself. His assistant installed the pipe and may have very well intended for his boss, the plumber, to decide whether or not a vent was needed behind the wall (air admittnace valves are also popular here). The image I uploaded here meets the German DIN standard for venting. Regardless of what the DIN standard is here, for my own piece of mind, I will ask the plumber to fully explain how the bathroom is being vented. Thanks to everyone for your feedback - much appreciated!

 

[havasu]

Believe it or not, cement/backer board is only recommended for pools, public showers, etc. green board is still the standard and considered A-okay for bathrooms.

That is crazy! I'm guessing anyone who is use to American plumbing will pull out their hair when seeing the work in other countries.

 

[ned8675309]

I was a bit apprehensive when I saw the tiler putting up the green board. (The plumber was convinced it was waterproof - "wasserdicht" - until we corrected him and told him it was a water resistant paper backing). Ironically, I'm a 45 minute drive from Schlüter-Systems HQ, the German maker of bath waterproofing and tile installation products. Similarly, my region is well-known as a tool maker and building materials supplier. My wood floors come from a company located 1 hour away. But my experience with contractors here is that they follow the standard first and foremost. What may be actually needed for a particluar situation is secondary and is only implemented if the customer is knowledgeable enough - shouldn't we have a vent here? - and requests that it be done. Hence, my inquiries here on this forum. But in the end, I do think my plumber should explain exactly how the bathroom is being vented, and more importanly, if the particular circumstances warrant putting a vent after the trap. The how and why concerning standards, whether it's here, there, or wherever, raises interesting questions. Thanks to everyone for the help.

 

[user 32496]

I prefer cement board (Hardie backer or equivalent) behind tile but our old house in California, built in 1989, had green board behind the tile in the shower. When I tore the shower out to remodel the bathroom, the green board was in perfect condition. The biggest problem in that bathroom was the floor was carpeted originally, and the wood was rotted below the shower door which was a swing out type door.

As far as the venting requirements in Germany, I am having a hard time finding the standard online. I would guess it's similar to the US or even more strict. I don't think the photo you supplied accurately depicts the drain line requirements, for example, there are no "P" traps depicted in the photo so it's hard to get a feel for the code requirements.



Because physics in Germany are similar to physics in the US, @McEd69's statement that the trap weir cannot be higher than the vent opening holds true in Germany as well as the US.

The basic physics of how syphons are formed is the key to codes concerning vents. Your drain line cannot slope down more than 1 trap arm diameter before getting to the vent. Your drain line cannot elbow down prior to the vent.




Since there is no vent in the wall where the drain pipe disappears, there is no reason why it shouldn't have gone straight to the drain hole like you thought it should have gone.

BUT! . . . I assume there was a tub or a shower here before? My question is this. . .Is there a trap under the floor where the old drain is? It would make sense to have a trap under the floor if there was a tub or shower here before your renovation. In that case, you might have a double trap now.

 

[ned8675309]

Yes! Now that you mention it ... there was a tub in this bath space before and it may have been vented. This bathroom was 2 bathrooms 30 years ago. The bathtub /shower area belonged to one apartment and the toilet and sink to another apartment. This might also explain why things are the way they are. I looked at some photos with the old tub and pipes still in place. I can't quite follow how it was all put together. Perhaps someone with plumbing experience can make sense of it. Thanks for the feedback - much appreciated!
Photos:
1. old tub plumbing
2. old tub trap
3. old shower plumbing and new pipes/fittings
4. zoom-in old shower plumbing
5. shower before demolition

 

[sawsaw]

I was a bit apprehensive when I saw the tiler putting up the green board. (The plumber was convinced it was waterproof - "wasserdicht" - until we corrected him and told him it was a water resistant paper backing). Ironically, I'm a 45 minute drive from Schlüter-Systems HQ, the German maker of bath waterproofing and tile installation products. Similarly, my region is well-known as a tool maker and building materials supplier. My wood floors come from a company located 1 hour away. But my experience with contractors here is that they follow the standard first and foremost. What may be actually needed for a particluar situation is secondary and is only implemented if the customer is knowledgeable enough - shouldn't we have a vent here? - and requests that it be done. Hence, my inquiries here on this forum. But in the end, I do think my plumber should explain exactly how the bathroom is being vented, and more importanly, if the particular circumstances warrant putting a vent after the trap. The how and why concerning standards, whether it's here, there, or wherever, raises interesting questions. Thanks to everyone for the help.

Bitteschoen fur das

 

[user 32496]

Yes! Now that you mention it ... there was a tub in this bath space before and it may have been vented. This bathroom was 2 bathrooms 30 years ago. The bathtub /shower area belonged to one apartment and the toilet and sink to another apartment. This might also explain why things are the way they are. I looked at some photos with the old tub and pipes still in place. I can't quite follow how it was all put together. Perhaps someone with plumbing experience can make sense of it. Thanks for the feedback - much appreciated!
Photos:
1. old tub plumbing
2. old tub trap
3. old shower plumbing and new pipes/fittings
4. zoom-in old shower plumbing
5. shower before demolition

still can’t tell from these photos how the drain is vented.

 

[ned8675309]

Yeah, agreed. I guess I really need to ask the plumber how everything is being vented, and more importantly, if it is adequate enough or not. Thanks again for the help.