Ask Me Help Desk - Laundry Standpipe and Vent

Laundry Standpipe and Vent

A friend is replacing a stall shower with a tub & shower and replacing a nearby tub with a washer and dryer. I told her I could do the plumbing. But I chickened out on the new tub because it was a tight fit and the pipe angles a bit complicated. My friend hired a plumber. Because he was there, he also did the old-tub to laundry conversion. I could have done that, though it would have been jury rigged.

My question involves seconded guessing the plumber's work on the tub-to-laundry conversion. He's licensed and I assume experienced, so I hate to second guess him, but still, what he did seems to be a mistake and I'd like to ask him to knock down the price a bit without coming across as a cheapskate.

The tub was on the ground floor over a crawl space. The trap was under the floor, in the crawl space. The drain ran four feet over to a vent stack that was also the vent stack for the old stall shower. There, they connected to the main sewer pipe.

The plumber put in a standpipe for the laundry machine. He had the trap above the floor. I would have hooked into the old trap under the floor but I think under-floor traps for laundry aren't code.

But what really puzzled me, and what I think was unnecessary, was putting a connection to the vent next to the trap. To do that he ran a vertical pipe up inside the wall (which required cutting out Sheetrock) then horizontal over to the existing vent pipe.

This is what I would have done: No new connection to the vent pipe. The existing connection to the vent pipe was only four feet away and was downstream from the standpipe (as it would have to be to be an effective vent for the old tub). The extra plumbing he did wasn't much, but it took a long time because he had to rip out walls and it is now going to add a lot to the cost of this project for replacing the walls he ripped out.

So, my question is, did he have to do it that way?

Thanks

That depends on which code prevails in your location.

If you live anywhere where the UPC has been adopted, then each trapped fixture must have it's own vent.

I'm with you on the trap. I know of no code that forbids placing a trap under the floor, we do it all the time on second floor tubs and showers. Of course it would look neater under the sink but our codes,(The Standard Plumbing Code and local code) would allow it. About the vent, if the old tub vent were dry the plumber was wrong to run a new one, however if the old tub vent had something else draining into it from up above he did the right thing in running a new one. It all depends on if the old vent was a dry vent or not. Regards, Tom

Thanks, Tom. The vent has something draining into it but from the same level, not from up above. I'll discuss with the plumber why he did what he did. Maybe he'll admit he made a mistake. Or maybe there is some reason he did what he did that he can tell me. I'll post what his response is. Thanks again!

Thanks, Iam. The laundry trap shares a vent with the shower, same as it did when the trap was for a tub.

Quote:

Originally Posted by speedball1

I'm with you on the trap. I know of no code that forbids placing a trap under the floor

Well, now you know of at least two.

UPC 804.1:

"No trap for any clothes washer standpipe receptor shall be installed below the floor, but shall be roughed in not less than six (6) inches and not more than eighteen (18) inches above the floor."

Ditto for section 802.4 of the IPC

And the reason for that would be?

Quote:

Originally Posted by speedball1

And the reason for that would be?

Accessibility, but mostly, because the people in charge say so.

Y'know, it doesn't have to make sense, but it does have to be installed per code if the Plumber wants his job to pass inspection and he wants to avoid a potential lawsuit from the homeowner.

If the poster wanted to install the trap below the floor himself, then I would have stayed out of the post altogether, but that isn't the case here -- The OP was questioning the craftsmanship of a (hopefully) licensed Plumber and in that spirit I merely pointed out that the Plumber installed the trap, trap arm, drain and vent per code.

Yes, very odd that a laundry trap has to be above floor level but a trap for anything else doesn't have to be. It's PCV pipe. It's not as if you need accessibility to a clean-out plug at the bottom of the trap. And it's going to be walled in. But "ours is not to reason why, ours is but to follow code or try" or something like that.

The plumber is licensed but anyone can make a mistake, especially when trying to be creative with an existing structure. If he says it wasn't a mistake, I'll take his word for it.

The trap I understand (I understand that it's code but not the reason for it). I don't understand why he had to install a vent that connects to the existing vent about six feet above where the drain meets the existing vent. It's not because of the distance from the trap to the vent, that's 3 1/2 feet.

--Otto

Quote:

The trap I understand (I understand that it's code but not the reason for it).

Don't look for a reason. Codes don't have to make sense. Case in point. Growlers code mandates a air-gao on a dishwasher while mine gives you the option of installing a counter top air gap or a under counter high loop. We opted for the high loop in our area because it vgives less service problems. If it's a question of code I would check with growler. He's a bear on code and knows it backward and forward. Me? I'm just a old retired plumber whose code book is a little out of date the same as me. Let me know what your plumber says. Cheers, Tom

Quote:

Originally Posted by GenePoole

Yes, very odd that a laundry trap has to be above floor level but a trap for anything else doesn't have to be.

Actually, the only other traps that might find themselves below floor level are tubs, showers and floor drains -- And most of those in framed homes with crawl spaces are kept in insulated joist bays, right?

You wouldn't put a trap for a lavatory, kitchen sink, bar sink, laundry tub etc... below floor level, would you?

Quote:

It's PCV pipe. It's not as if you need accessibility to a clean-out plug at the bottom of the trap. And it's going to be walled in. But "ours is not to reason why, ours is but to follow code or try" or something like that.

Exactly.

Then again, the six inch requirement is a throwback to the days when traps were copper or Durham cast iron -- Which were notorious for rotting out when they came in contact with soil.

Quote:

The plumber is licensed but anyone can make a mistake, especially when trying to be creative with an existing structure. If he says it wasn't a mistake, I'll take his word for it.

>shrugs<

Personally, I don't think he made a mistake.

OTOH, I've dealt with numerous homeowners over the years who felt it was imperative that they question my every move -- Go figger.

Apparently the hoops one must jump through to gain the accreditation are lost on most homeowners.

Quote:

The trap I understand (I understand that it's code but not the reason for it).

That's an easy one -- The trap creates a water barrier that prevents sewer gas from reentering the structure.

Quote:

I don't understand why he had to install a vent that connects to the existing vent about six feet above where the drain meets the existing vent. It's not because of the distance from the trap to the vent, that's 3 1/2 feet.

Right.

But as I explained earlier in this thread -- Every trapped fixture must have its own vent.

I'm truly sorry you see bogeymen and Shysters under every rock and crevice, but the bottom line is that you (leastways from your description) got a professional installation that will function properly, take anything you can throw at it and will not reduce the asking price of the home if it is ever put on the market for sale.

Quote:

Originally Posted by speedball1

Don't look for a reason. Codes don't have to make sense. Case in point. Growlers code mandates a air-gao on a dishwasher while mine gives you the option of installing a counter top air gap or a under counter high loop.

The requirement for an air gap on a dishwasher makes perfect sense to me, Tom.

I'll tell you what doesn't make sense:

It's your code that in one breath mandates that a dishwasher drain hose *MUST* be above the flood rim -- And then in the very next breath says that high-looping below the flood rim is also acceptable.

Why am I the only one who see the dichotomy presented by this apparent incongruity?

Growler! You are nit picking against success.

Quote:

It's your code that in one breath mandates that a dishwasher drain hose *MUST* be above the flood rim -- And then in the very next breath says that high-looping below the flood rim is also acceptable.

Just one more reason that I think a lot of codes are stupid and contradictory. Look at yours that mandate a vent for every fixture. Over kill? Hell yes, when you consider that wet vents have been working in my area forever without any problems.
As a working plumber I'm aware that you have to follow code in your area but for Gods sake does it have to be written in stone? Think outside the box once ibn a while and simply go with what works best. (like a high loop, Just had to throw that in.) Have a great weekend. Tom