Vent Stack Question.

[that_guy]

I have a 1 and 1/2 story home and would like to add a washroom in the basement below the 1 story portion of the home. Is there a concern with having the vent stack come up through that one story. The exisiting vent stack goes up through both floors.

Thanks.

[tooltroll]

So the new washroom is not anywhere near the old stack? Sure, you can run a new stack up, but the code dictates how far the outlet (top end) has to be from doors, windows, the roof, etc., Remember, this is where sewer gas escapes (rather that into your kitchen/bathrooms,) so you don't want that lovely perfume wafting into your house through an open window! :wink:

[Sparks]

:lol: True indeed. Although I've seen this done alot around here, just check with your local codes to see what they require regarding height above roof line etc, etc. Sometimes this is the only way if you can't easily access the existing stack and t- into it.

[that_guy]

Thanks guys. I think that based on what you told me I may have some challenges (code and otherwise) but thanks again for your help - at least now I understand.

[rabadger]

Does code allow you to tie in the new stack into the old one in the attic?

[Tom R]

Does code allow you to tie in the new stack into the old one in the attic?

Yes, - - this is called re-venting, - - and is usually the best way to do it. Find a path to get your vent up to the attic and 'tie-in' to the existing vent, - - no sense putting more holes through the roof.

The other choice is venting out the foundation wall and up along the outside of the house, - - but such a method will look every bit as ugly as it sounds.

Another choice yet is a 'wet-vent', - - but that's somewhat more complicated, - - and illegal in most places.

[rabadger]

Thanks Tom R. I have seen it done but didn't know if it was per code.

[Sparks]

Tom, I believe wet venting still requires a vent stack. You are just using drain piping for drainage and venting but a stack is still required, tied in or separate.

[Tom R]

Correct, - - I'm talking about 'wet-venting' into an existing stack, - - although it sounds too far away in his case.

[Sparks]

I figured you knew your stuff, just testing ya :D , I've been seeing alot of new houses these days with multiple stacks. Especially on houses as described here, sometimes ya gotta make more holes, no big deal right.

[roger g]

Yo Sparks, Funny you should mention about new houses having lots of stacks. I started taking notice just a couple of days ago just how many more stacks I see on one roof. A house just down the road from my project has in one place 2 stacks about 4 feet from each other. I noticed it because the one stack is right on a ridge. Out here on the west west west coast our stacks (which protrude through the roof) only look about 1 1/4 inch not like the monsters you see out east where it is cold.



roger

[Sparks]

Yeah around here they mandate 3" min. for snow buildup problems that may occur. I know some of these stacks are also for high-effeciency furnaces and hw tanks as sometimes they vent these through the roof instead of side wall. But I guess if you have kids, you can never have enough bathrooms.

[Dormer_man]

Does anyone know the code for how many roof stacks you need to vent a house based on the number of bathrooms?

It seems like you might get more sewer gas building up if you use more bathrooms, possibly overwhelming just one stack.

[Sweep]

The purpose of fixture venting is to allow air to enter the system in order to prevent a vacuum when water is draining. You can sometimes avoid having an immediate upward vent at a fixture by increasing the size of the fixture drain pipe so that the vacuum won't occur during normal use. This is called "wet venting" since the relief air and the waste water share the same pipe for a limited distance. The distance from the fixture to the real vent for a given pipe size is spelled out in the code.

I had a boss who would give me hell if I labeled a stack vent as a vent stack on a drawing. If the roof vent is a continuation of the waste stack it is a stack vent. Vent stacks serve multiple vents, but no waste.

[Dormer_man]

Thank you for Sweep, I never knew this before. You know your stuff.

Sort of like draining the oil on your lawn tractor, it drains much faster if you take the filler cap off.

[tooltroll]

F'rinstance, I just plumbed a couple of suites for my ex-landlord, and since I was able to rough everything in within 6' of the 3" stack, no venting is required by code (here.)

However, having spent a month in one of the suites, I can testify that CODE IS NOT SUFFICIENT! Every time the toilet was flushed, everything else gurgled, indicating vacuum in the line. I would've ran revents, but the customer was too cheap, and specified everything be run without. (Since code allows it... sigh)

[Sparks]

So when the gurgling was taking place, more than likely the traps were being emptied by the siphoning effect of flushing the toilet and sewer gases were entering the dwelling. Is this what you are saying? Canada has no venting requirements? A properly designed wet vent system should prevent a vacuum/gurgling/siphoning problem like you described.

[tooltroll]

The venting requirements were supposedly addressed by having no more than 6' of 1-1/2 ABS from the 3" line, that being the local code recommendation for wet venting with that size... but yeah, I'm saying that they gurgled (lightly) which indicates suction when the turlet flushed, and possibly draining the traps.

Just goes to show that the code may be legal, but it ain't always enough... I'm never going to omit revents again, no matter how cheap the customer is. :D

[Tom R]

I don't know, - - sounds to me like that 3' pipe might be partially clogged up.

[tooltroll]

Nope. Brand new 3" stack... put it there myself...

[roger g]

When I built my first house in the early seventies, I remember that being within a certain distance of the vent I didn't need to individually vent the fixtures. (Canada). BUT recently I haven't seen anything about that in anything I've read in Canada. I wonder if it has changed. I also wonder that if it still exists does it apply to more than a bungalow which is what I had.
The City of Winipeg Engineering Dept has some great stuff on line for plumbing and stuff.



roger