I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.

I'd like to see who is "all wet" so I know who to believe. The layout
is pretty simple and to the best of my notes I'll try to recall what
the last guy said.

I have a single bathroom (tub/lav/toilet) on the first floor, as well
as a kitchen sink and dishwasher. A single 3" PVC pipe is used for
the drain on all of those items, and it extends straight up through
the roof without anything else connecting to it.

The bathroom on the second floor would be right next to the 3" pipe,
and the other contractors said they could just drain right into it,
and that it would also serve as the vent, as long as everything was
within 5' of it upstairs.

The last guy said that you can't drain fixtures from the second floor
into the same drain used for the first floor, since the first floor
fixtures are being "wet vented" into that pipe. To add the bathroom
upstairs would mean that you would have fixtures "wet vented" above
others that were also "wet vented." This contractor says the extra $$
is to add a second 3" PVC drain all the way to the basement and extend
it through the roof. When I spoke to the first 2 contractors they
told me that he was nuts, and that they could absolutely be vented and
drained into the same "stack" and that the "DFUs" were not exceeded.
No idea what a DFU is.

So, help! Who is correct? Can I add the second bathroom upstairs
with the same vent/waste pipe?

Thanks all!

On Wed, 02 Feb 2005 00:10:14 -0500, Peter Langevin
wrote:

I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.

I'd like to see who is "all wet" so I know who to believe. The layout
is pretty simple and to the best of my notes I'll try to recall what
the last guy said.

I have a single bathroom (tub/lav/toilet) on the first floor, as well
as a kitchen sink and dishwasher. A single 3" PVC pipe is used for
the drain on all of those items, and it extends straight up through
the roof without anything else connecting to it.

The bathroom on the second floor would be right next to the 3" pipe,
and the other contractors said they could just drain right into it,
and that it would also serve as the vent, as long as everything was
within 5' of it upstairs.

The last guy said that you can't drain fixtures from the second floor
into the same drain used for the first floor, since the first floor
fixtures are being "wet vented" into that pipe. To add the bathroom
upstairs would mean that you would have fixtures "wet vented" above
others that were also "wet vented." This contractor says the extra $$
is to add a second 3" PVC drain all the way to the basement and extend
it through the roof. When I spoke to the first 2 contractors they
told me that he was nuts, and that they could absolutely be vented and
drained into the same "stack" and that the "DFUs" were not exceeded.
No idea what a DFU is.

So, help! Who is correct? Can I add the second bathroom upstairs
with the same vent/waste pipe?

Thanks all!
Your plumber knows what he is talking about and is proposing to do the
job right- The other two are hacks and clearly don't understand code
requirements for venting- DFU is drain fixture unit, has nothing to
do with this situation-

Dan

The wet vent guy is all wet for an extra 5000

As I recall, when you are talking about a bathroom the more expensive
contractor is correct and you do want to follow his procedure or you may
find you will loose the water forming the traps in the lower baths when the
upper toilet is flushed.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math
"Peter Langevin" wrote in message
...
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.

I'd like to see who is "all wet" so I know who to believe. The layout
is pretty simple and to the best of my notes I'll try to recall what
the last guy said.

I have a single bathroom (tub/lav/toilet) on the first floor, as well
as a kitchen sink and dishwasher. A single 3" PVC pipe is used for
the drain on all of those items, and it extends straight up through
the roof without anything else connecting to it.

The bathroom on the second floor would be right next to the 3" pipe,
and the other contractors said they could just drain right into it,
and that it would also serve as the vent, as long as everything was
within 5' of it upstairs.

The last guy said that you can't drain fixtures from the second floor
into the same drain used for the first floor, since the first floor
fixtures are being "wet vented" into that pipe. To add the bathroom
upstairs would mean that you would have fixtures "wet vented" above
others that were also "wet vented." This contractor says the extra $$
is to add a second 3" PVC drain all the way to the basement and extend
it through the roof. When I spoke to the first 2 contractors they
told me that he was nuts, and that they could absolutely be vented and
drained into the same "stack" and that the "DFUs" were not exceeded.
No idea what a DFU is.

So, help! Who is correct? Can I add the second bathroom upstairs
with the same vent/waste pipe?

Thanks all!

Then what does a high rise building do, you dont see 100 vents comming
out of a 100 story building. My 3 story apt gas 1 stack per 3 toilets

Ive also looked at many roofs of 3 storey houses with multiple baths
one on every floor using the same stack and have instaled 4 basement
apts using the same stack as the 2 above, Ive not had a problem in 15
yrs on 4 conversions. Im no plumber but Ive " shared" stacks. You are
talking "Air" venting which should not " suck " anything out of a
different toilet . I ve also been on a few larger apt building roofs ,
I have only seen 1 stack per run. If that were the case then large
buildings of 100 - 500 toilets would have the roofs covered with stack
vents. Pouring 5 gallon of water down a vent won`t creat a suction,
maybe pouring 500 gallons in a few seconds will. I still say the 5000+
guy is wrong , unless it is a 1/4 " pipe which it surely is not. . It is
most likely 3" or 4 " venting.

"m Ransley" wrote in message
...
Then what does a high rise building do, you dont see 100 vents comming
out of a 100 story building. My 3 story apt gas 1 stack per 3 toilets


I own a high rise condo. I don't know the details but the "vent function"
is accomplished without any obvious vent. There are 26 floors in each
building and about 30 bathrooms and 20 kitchens per floor. Note that
during extreme weather you can see the water level in the toilet bowl vary a
good fraction of an inch.

John Im sure you have 1 stack per run through the roof. So you may only
have 1 if everything is inline. It may only extend up 5" with a vent
hood but it is there, perhaps hidden among other roofing equipment as to
not be obvious or in the open.

Simple, an apartment building combines all the drains into one that leaves
the building. The vent works the same way they are all combined into one
vent that runs through the roof. Basically you only need one drain stack and
one vent stack to handle all plumbing. Sometimes because of horizontal
spacing you may have more than one vent through the roof.

The more expensive plumber is correct in that you need a vent stack from the
bottom to parallel the drain stack, which can combine together in the attic
to vent through the roof.

"m Ransley" wrote in message
...
Then what does a high rise building do, you dont see 100 vents comming
out of a 100 story building. My 3 story apt gas 1 stack per 3 toilets

Peter Langevin wrote:
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.
SNIP

The last guy is 100% correct.

Here is why:
When you flush the upstairs toilet, the slug of water rushing down
the stack will create a vacuum as it passes the lower toilet and
will try (might succeed) to siphon the water out of the bowl.

In addition, the sinks/tubs on the 1st floor have vent connections
into the stack using TEE fittings. That slug of water from the 2nd
floor will easily branch off into those vent lines, disrupting trap
seals on the sinks.

In h-rise bldgs, there is not one single stack. There will be
at least one soil stack and a separate vent stack. All waste
will drop into the soil stack and all traps will be connected
to the vent stack.

Go to the BigBox store and get a basic plumbing book or go the
local library. Good books will have pics showing how it is
correctly done.

Or, call the town inspector and ask. After all, the 2 guys with
the low bids *will* be getting permits. Right??

It's a big job in a residence to add another stack thru existing walls.

Jim

"Peter Langevin" wrote in message
...
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. (snip)

I asked a venting question here a while back and someone
posted this instructive link:
http://www.pmengineer.com/CDA/Articl...101269,00.html

Brian, in Cedar

Now im getting a bit confused, I put in basement apatments and hooked
everything to the main 4" or so drain that takes care of 2 upper floors
and all is fine for years. I thought the main drain was the vent as it
terminated out the roof. or am I wrong. It all works well though.

Peter Langevin wrote:
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.

I'd like to see who is "all wet" so I know who to believe. The layout
is pretty simple and to the best of my notes I'll try to recall what
the last guy said.

I have a single bathroom (tub/lav/toilet) on the first floor, as well
as a kitchen sink and dishwasher. A single 3" PVC pipe is used for
the drain on all of those items, and it extends straight up through
the roof without anything else connecting to it.

The bathroom on the second floor would be right next to the 3" pipe,
and the other contractors said they could just drain right into it,
and that it would also serve as the vent, as long as everything was
within 5' of it upstairs.

The last guy said that you can't drain fixtures from the second floor
into the same drain used for the first floor, since the first floor
fixtures are being "wet vented" into that pipe. To add the bathroom
upstairs would mean that you would have fixtures "wet vented" above
others that were also "wet vented." This contractor says the extra $$
is to add a second 3" PVC drain all the way to the basement and extend
it through the roof. When I spoke to the first 2 contractors they
told me that he was nuts, and that they could absolutely be vented and
drained into the same "stack" and that the "DFUs" were not exceeded.
No idea what a DFU is.

So, help! Who is correct? Can I add the second bathroom upstairs
with the same vent/waste pipe?

DFU = "Drainage Fixture Unit"

It's been a couple of years since I've had to deal with this, but last time I
checked most residential codes only allow wet venting for fixtures on the same
floor, so if they're planning on just dumping the 2nd story waste into the
existing vent stack, that's a no-no.

That's not to say that a new soil stack all the way to basement is needed -- if
the existing soil stack (and associated vent stack) is big enough (that's where
the DFU issue comes in), then it might be possible to use the existing vent
stack as the 2nd story soil stack (sliced off accordingly), and run a new vent
stack (starting at the existing hole in the roof). down to the 2nd and 1st
floors.

I'm not a plumber by trade, 'tho, so something may've changed in one of the
codes in the last couple of years.

"Speedy Jim" wrote

The last guy is 100% correct.

Here is why:
snip
It's a big job in a residence to add another stack thru existing walls.

Jim

That Speedy Jim sure knows his sh!t!!!! )

Brian Barnson wrote:
"Peter Langevin" wrote in message
...
I live in a 1 1/2 story home, one bathroom on the first floor.
I had
a remodeling contractor out last week to give me an estimate
to add a
second bathroom to the upstairs bedroom. (snip)

I asked a venting question here a while back and someone
posted this instructive link:
http://www.pmengineer.com/CDA/Articl...101269,00.html

Brian, in Cedar

Thanks, Brian; great link!

Pop

Speedy Jim wrote:
Peter Langevin wrote:
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were
doing. SNIP

The last guy is 100% correct.

Here is why:
When you flush the upstairs toilet, the slug of water rushing down
the stack will create a vacuum as it passes the lower toilet and
will try (might succeed) to siphon the water out of the bowl.

That's only if the water moves like a cylindrical hunk of Jello. I can't
imagine the amount of water it would take to fill the cross-section of a
3-4" pipe under the influence of gravity. I don't think you can do it absent
much higher pressure, like a fire hose. The water is going to run down the
sides of the pipe maybe 1/16" thick.

Now is some kind of SOLID plug (like a diaper or football) is moving down
the drain, maybe you can generate a vacuum. Water alone won't do it.


It's a big job in a residence to add another stack thru existing
walls.

Here's a compromise: Do the remodel without the new stack. If it doesn't
work, retrofit enough parts to make it work.

"m Ransley" wrote in message
...
Then what does a high rise building do, you dont see 100 vents comming
out of a 100 story building. My 3 story apt gas 1 stack per 3 toilets

All the vents can be ran back together into one at some point.
The problem here is one stack for drain and vent, a big no no!
Greg

"m Ransley" wrote in message
...
Now im getting a bit confused, I put in basement apatments and hooked
everything to the main 4" or so drain that takes care of 2 upper floors
and all is fine for years. I thought the main drain was the vent as it
terminated out the roof. or am I wrong. It all works well though.


It may work, but it is not up to code in most areas.
Just 'cuz it works, don't mean it is right!
Greg

Wet venting should be avoided in this instance...the guys trying to save you
a few bucks will end up screwing you.

Plumbing is broken into two areas, that which is seen and that which
carries. A contractor willing to cut corners and ignore code will not save
you money...and the plumbing inspector will not allow the wet vent. BTW,
wet venting is intended to vent closely adjacent fixtures, not those on
seperate levels, i.e., a sink can be used to wet vent a toilet or a shower,
however, a toilet can never be used to wet vent another DFU. The two cheap
quotes are attempting to use a toilet to wet vent other fixtures.
"Andy Hill" wrote in message
...
Peter Langevin wrote:
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were doing.

I'd like to see who is "all wet" so I know who to believe. The layout
is pretty simple and to the best of my notes I'll try to recall what
the last guy said.

I have a single bathroom (tub/lav/toilet) on the first floor, as well
as a kitchen sink and dishwasher. A single 3" PVC pipe is used for
the drain on all of those items, and it extends straight up through
the roof without anything else connecting to it.

The bathroom on the second floor would be right next to the 3" pipe,
and the other contractors said they could just drain right into it,
and that it would also serve as the vent, as long as everything was
within 5' of it upstairs.

The last guy said that you can't drain fixtures from the second floor
into the same drain used for the first floor, since the first floor
fixtures are being "wet vented" into that pipe. To add the bathroom
upstairs would mean that you would have fixtures "wet vented" above
others that were also "wet vented." This contractor says the extra $$
is to add a second 3" PVC drain all the way to the basement and extend
it through the roof. When I spoke to the first 2 contractors they
told me that he was nuts, and that they could absolutely be vented and
drained into the same "stack" and that the "DFUs" were not exceeded.
No idea what a DFU is.

So, help! Who is correct? Can I add the second bathroom upstairs
with the same vent/waste pipe?

DFU = "Drainage Fixture Unit"

It's been a couple of years since I've had to deal with this, but last
time I
checked most residential codes only allow wet venting for fixtures on the
same
floor, so if they're planning on just dumping the 2nd story waste into the
existing vent stack, that's a no-no.

That's not to say that a new soil stack all the way to basement is
needed -- if
the existing soil stack (and associated vent stack) is big enough (that's
where
the DFU issue comes in), then it might be possible to use the existing
vent
stack as the 2nd story soil stack (sliced off accordingly), and run a new
vent
stack (starting at the existing hole in the roof). down to the 2nd and 1st
floors.

I'm not a plumber by trade, 'tho, so something may've changed in one of
the
codes in the last couple of years.

Greg O ) said...


"m Ransley" wrote in message
...
Now im getting a bit confused, I put in basement apatments and hooked
everything to the main 4" or so drain that takes care of 2 upper floors
and all is fine for years. I thought the main drain was the vent as it
terminated out the roof. or am I wrong. It all works well though.


It may work, but it is not up to code in most areas.
Just 'cuz it works, don't mean it is right!

I believe in our code (and probably others) a wet stack may be used for
venting only where it carries a single sink or tub, but not a toilet,
from above.

Even so, I lean towards only using only dry stacks for venting.

Dry stacks start with the vent on the roof and proceed down to each
fixture they serve. Branches for each fixture must take off the main
stack above the flood line for the fixture. Therefore, no fixture can
ever have water from it flow into the dry stack.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove the capital letters!

"JerryMouse" wrote in message
...
Speedy Jim wrote:
Peter Langevin wrote:
I live in a 1 1/2 story home, one bathroom on the first floor. I had
a remodeling contractor out last week to give me an estimate to add a
second bathroom to the upstairs bedroom. His quote came back
significantly ($5000) higher than the other 2 I got, and when I asked
him what the difference was he said it was due to a "wet venting
issue." I mentioned that 2 other contractors hadn't mentioned it,
and he essentially told me that they didn't know what they were
doing. SNIP

The last guy is 100% correct.

Here is why:
When you flush the upstairs toilet, the slug of water rushing down
the stack will create a vacuum as it passes the lower toilet and
will try (might succeed) to siphon the water out of the bowl.

That's only if the water moves like a cylindrical hunk of Jello. I can't
imagine the amount of water it would take to fill the cross-section of a
3-4" pipe under the influence of gravity. I don't think you can do it
absent
much higher pressure, like a fire hose. The water is going to run down the
sides of the pipe maybe 1/16" thick.

Now is some kind of SOLID plug (like a diaper or football) is moving down
the drain, maybe you can generate a vacuum. Water alone won't do it.

I don't know about you, but when I use the toilet there is a hell of a lot
more than water going down the waste line, not quite a football but close.
And if you have any women in the house, the amount or toilet paper used is
incredible. With a wife and two daughters they can use over a roll a day.
What's up with that anyway? They roll about 20' of it around their hand just
to dab off after they pee and then repeat once or twice.

CR





It's a big job in a residence to add another stack thru existing
walls.

Here's a compromise: Do the remodel without the new stack. If it doesn't
work, retrofit enough parts to make it work.