Ask Me Help Desk - Rough plumbing for stacked bathrooms

Hello,

I'm putting in 2 new bathrooms which will be stacked. Each bathroom will have a tub/shower unit, toilet and sink. I plan on running a 3" stack that will connect into clay sewer drain in crawl space and run all the way up to attic space. Each toilet will connect into this 3" stack with 3" pipe as well.

Is it ok if I connect the shower/tub with 2" pipe to the toilet run and then connect the sink with 1 1/2" pipe to the shower/tub run?

Can I connect the sink directly to the toilet run and the shower/tub directly to the toilet run instead if I like?

Can tee's be used on both horizontal and vertical drain lines as long as they are not on their back?

Wye's can be used on both drain and vent lines in any position correct?

I plan on running a separate vent (1 1/2" pipe) from both the 1st floor sink and shower/tub unit up to the 2nd floor and teeing in the 2nd floor shower/tub and sink (above flood rim) and continuing the 2 vents into attic space and connecting to main stack, is this called "dry venting" and is it OK?

Finally, would a 2" vent through the roof be sufficient or would I need to go to 3"?

Any help would be greatly appreciated. Thanks!

Oops.. forgot to ask is a 3" main stack ok or would it need to be 4"? Thanks!

According to our Plumbing Code, none of what you described would be correct in So.California. I'll let other plumbers in this forum to lead you through this.

Hi Steve:

As Milo has pointed out... plumbing codes vary by state so you really need to check with your local plumbing inspector to see what code is being used in your area and if what I present below can be used in your area... ok? I am using Massachusetts Uniform State Plumbing Code, '93.

First, you will need a REDUCING FERNCO COUPLING (see 1st picture) to transition from the clay pipe in the crawl space to the 3" PVC (or ABS) pipe for this installation.

You want to install a 3" dandy cleanout (see 2nd picture) just after you come off the clay pipe, preferably at or near the base of the 3" waste stack so you can snake the drain (up or down) if needed in future.

TEES cannot be used on horizontal drain lines except as a vent connection (unless wet venting which I will explain in a minute). Tees can be used on vertical drain pipes to stub out for a fixture (tub, toilet, sink, etc.).

WYES can be used almost anywhere except to stub out for sinks (if use a wye and 45 degree fitting it lowers the vent/ptrap relationship and it actually negates the vent).

Now...lets name each bathroom you are piping as BATH1 (lower floor) and BATH2 (upstairs bath)..ok??

At Bath1 you will EITHER be required to install an individual vent to each fixture as follows: Toilet gets 2" vent, lavatory gets 1.5" vent and tub/shower unit gets 1.5" vent OR you may be able to WET VENT bath1 using a 2" (increased here) sink vent to vent the toilet, tub and the sink itself (see picture below).

The picture below is inaccurate in that it does not show the WYE fittings required for horizontal piping, so be sure to install WYE fittings off the 3" toilet pipe to pick up the 2" sink and tub drain... The 2" horizontal waste pipe picks up the sink and tub (tub reduces to 1.5" @ ptrap) and here the 2" sink vent must continue up to next bathroom and can connect there at least 6 inches above flood level rim of the sink in that bathroom... not back into the waste stack as in the picture below because you have a bathroom above this... ;)

But I think you knew that by your description! Anyway, remember that I just presented an oversimplified description of WET VENTING a bathroom... it may or may not be acceptable in your area and you need to check with your local plumbing inspector.. ok?

Now, at Bath2 you should be able to STACK VENT the bathroom. Here, the tub connects into the stack BELOW the toilet using a special side inlet fitting OR can also install a 3"x1.5" tee fitting below the tee fitting to pick up the toilet. Then install 3" tee fitting to pick up toilet, and finally install a 3" tee fitting to pick up toilet, and finally install a 3" tee above the floor and run the waste line to sink so it ends at about 17-18" off finish floor (the sink itself should be within 5 feet of the stack). No individual vents required... ;)

So... discuss WET VENTING Bath1 and STACK VENTING Bath2 (on top floor) with local inspector and see what he thinks... ok? Let us know what he says, please! Also, let us know what version of code you guys use in your area... always interesting to see what others are doing across the country!

Finally, the 1.5" vent for the kitchen sink is correct and I think you will need a 3" vent to penetrate the roof for these bathrooms. In my area we stub above roof 18" tee above the floor and run the waste line to sink so it ends at about 17-18" (lots of snow here). In Milo's area it is 12"-24" (I think)... just proving that codes vary quite a bit by region!

Check your codes.. let us know what you think... chat soon... MARK

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Thanks Mark, I appreciate your helpful reply.

Can I use a donut or an "any bore" to connect the 3" PVC to the INSIDE of the clay pipe as far as being allowed by code? The bell is broken off of this clay pipe partially and I do not wish to try and cut it off completely to put the fernco coupling on (afraid of cracking further).

The clay pipe is also laying horizontally (sloped of course), so is there a problem with code allowing me to use this type of fitting in a non-vertical application?

I was going to stick the 3" PVC in the clay pipe about a foot or so from the end and seal with the donut or any bore and then come out with (2) 45's or a 90 to get vertical and then go to a tee as you suggested for cleanout and then to (2) more 45's and then to 3" stack. Is this too many bends?

I have to use the last (2) 45's to offset the stack into the wall (stack will come out of crawl space and immediately 45 into wall at sill plate).

Regarding bathroom group 1, the toilet will be about 9 - 10 feet from stack, any problem with this?

Can the 3" x 2" WYE be located anywhere on this 3" toilet run to pickup sink and then shower/tub (such as middle of the run)?

And lastly, can local towns have there own specific plumbing codes or does every town have to follow 1 of the 3 plumbing codes (I think there is 3 right?)?

Thanks again for your advice!

Quote:

Originally Posted by massplumber2008

Hi Steve:

As Milo has pointed out...plumbing codes vary by state so you really need to check with your local plumbing inspector to see what code is being used in your area and if what I present below can be used in your area...ok?? I am using Massachusetts Uniform State Plumbing Code, '93.

First, you will need a REDUCING FERNCO COUPLING (see 1st picture) to transition from the clay pipe in the crawl space to the 3" PVC (or ABS) pipe for this installation.

You want to install a 3" dandy cleanout (see 2nd picture) just after you come off the clay pipe, preferably at or near the base of the 3" waste stack so you can snake the drain (up or down) if needed in future.

TEES cannot be used on horizontal drain lines except as a vent connection (unless wet venting which I will explain in a minute). Tees can be used on vertical drain pipes to stub out for a fixture (tub, toilet, sink, etc.).

WYES can be used almost anywhere except to stub out for sinks (if use a wye and 45 degree fitting it lowers the vent/ptrap relationship and it actually negates the vent).

Now...lets name each bathroom you are piping as BATH1 (lower floor) and BATH2 (upstairs bath)..ok??

At Bath1 you will EITHER be required to install an individual vent to each fixture as follows: Toilet gets 2" vent, lavatory gets 1.5" vent and tub/shower unit gets 1.5" vent OR you may be able to WET VENT bath1 using a 2" (increased here) sink vent to vent the toilet, tub and the sink itself (see picture below).

The picture below is inaccurate in that it does not show the WYE fittings required for horizontal piping, so be sure to install WYE fittings off the 3" toilet pipe to pick up the 2" sink and tub drain...The 2" horizontal waste pipe picks up the sink and tub (tub reduces to 1.5" @ ptrap) and here the 2" sink vent must continue up to next bathroom and can connect there at least 6 inches above flood level rim of the sink in that bathroom.....not back into the waste stack as in the picture below because you have a bathroom above this...;)

But I think you knew that by your description!! Anyway, remember that I just presented an oversimplified description of WET VENTING a bathroom...it may or may not be acceptable in your area and you need to check with your local plumbing inspector..ok??

Now, at Bath2 you should be able to STACK VENT the bathroom. Here, the the tub connects into the stack BELOW the toilet using a special side inlet fitting OR can also install a 3"x1.5" tee fitting below the tee fitting to pick up the toilet. Then install 3" tee fitting to pick up toilet, and finally install a 3"x1.5" tee above the floor and run the waste line to sink so it ends at about 17-18" off finish floor (the sink itself should be within 5 feet of the stack). No individual vents required...;)

So....discuss WET VENTING Bath1 and STACK VENTING Bath2 (on top floor) with local inspector and see what he thinks...ok?? Let us know what he says, please!! Also, let us know what version of code you guys use in your area...always interesting to see what others are doing across the country!

Finally, the 1.5" vent for the kitchen sink is correct and I think you will need a 3" vent to penetrate the roof for these bathrooms. In my area we stub above roof 18"-24" (lots of snow here). In Milo's area it is 12" (I think), and in Tom's area (Florida) it is 6" (I think).....just proving that codes vary quite a bit by region!!

Check your codes..let us know what you think....chat soon...MARK

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You should cut the clay pipe. This is a sewer pipe and connection is very important. If the pipe is old and fragile, use 4" diamond blade. It will cut through clay as through butter. Use Flex Seal couplings to connect PVC transitional fitting.

Hi Steve...

As a plumber, I would be required to cut the clay pipe (diamond saw) or I would be required to go back to the next piece of clay pipe that is in good shape...

I cannot just stick the pipe inside the pipe as the lip of the pipe would eventually catch stuff and would probably cause the pipe to back up sooner than later.. ;)

Here, if say a 6" clay pipe...then a 6"x4" fernco will be the way to go as the inside of 6" clay is approximately equal to inside of 4" pvc pipe... ok?

Stick with the 45s off the clay... use 2-45s to make a 90 then clean out then 45s as needed!

9-10 feet off the stack for Bath1 is fine, if wet venting is allowed. The 3"x2" wye can be used in the middle of run but should not connect further than 8 feet from the toilet elbow.

Let us know if need more...

MARK

Quote:

Originally Posted by stevekem

Oops.. forgot to ask is a 3" main stack ok or would it need to be 4"? Thanks!

Our code mandates that one three inch vent be installed on every single family dwelling. As a rule we take this vent off the kitchen since changes in our code require us to run kitchen drainage at a minimum of three inches. This is due to the additional garbage produced by the disposal.
Good luck, Tom

Finally got the clay pipe cut off with the suggestions from Milo and Massplumber to use a diamond blade on my angle grinder. I ended up making 2 trips to Lowe's to get the right blade (purchased wrong size first time). Yep it cut it off like butter, I took my time though to make sure I didn't mess it up, but I got the fernco on :) Now here my new questions...

Could I start the 4" fernco end with a pvc reducing bushing (4" x 3") then a street 45, street 90, cleanout tee, sanitary tee (for 1st floor toilet, etc), 45, 45, then soil/vent stack?

I know it's alot of bends, but I am faced with a very tight space and I cannot think of anything else that would work.

Would there be any code violations in this setup such as usng the reducing bushing in the fernco?

Also, I forgot that I will have a gas fired tankless water heater mounted in my 1st floor bath closet. This unit will have a condensate drain. Should/could I install a laundry standpipe in the closet for this limited amount of water? Would there need to be another vent for this? Where would this pipe into my 1st floor bathroom group at if I am using the following setup:

3" from stack to toilet, 2" off toilet run to sink, 2" off sink run to shower/tub, 2" vent off sink stub out to attic and vented into main stack

Thanks again!

Hi Steve.. good for you!

If possible, don't reduce right out of the end of the pipe in this case. Here, you want to install a 4"x3"wye fitting and install a 4" end cleanout in the end of the 4" end cleanout in the end of the 4" wye and then a 3" street 45 degree fitting into the 3" branch of the 4" wye and then a 3" wye fitting. Then if can fit it, you want the 3" dandy cleanout installed next in line and then fittings as required to accomplish job!

That is how my code book says it needs to be done, so yes code disagrees with reducing drain line right out of the fernco without full size end cleanout for future snaking of drain (and since older clay pipe more cleanouts are better... just in case... ;) ).

The tankless water heater drain can come off the 3" vertical stack as long as have a 1.5" branch of the 4" vent for the drain (kinda like a sink).

The rest sounds good!

Let us know what you think... Mark

Hi Mark,

Thanks again for your reply. Unfortunately I do not have the space to fit the wye in right out of the fernco. The clay pipe sticks out horizontally right at the corner of the crawl space foundation, with the end facing the walls. I have just enough room to get that 3" street 45 and 90 in to get the pipe going vertically.

Is there anything else I could do that you can think of? I took a picture of the pipe with my camera phone today, but my phone won't let me upload it the computer :mad:

If there is room (a big if), would it be allowed to add a 4" street 45 and 4" street 90 directly in the fernco, then add a 4" cleanout tee with a reducing bushing at the top of cleanout taking it down to 3", then my sanitary tee and (2) 45's?

Thanks again!

Quote:

Originally Posted by massplumber2008

Hi Steve..good for you!!

If possible, don't reduce right out of the end of the pipe in this case. Here, you want to install a 4"x3"wye fitting and install a 4" end cleanout in the end of the 4"x3" wye and then a 3" street 45 degree fitting into the 3" branch of the 4"x3" wye fitting. Then if can fit it, you want the 3" dandy cleanout installed next in line and then fittings as required to accomplish job!!

That is how my code book says it needs to be done, so yes code disagrees with reducing drain line right out of the fernco without full size end cleanout for future snaking of drain (and since older clay pipe more cleanouts are better...just in case...;) ).

The tankless water heater drain can come off the 3" vertical stack as long as have a 1.5" ptrap and a separate 1.5" vent for the drain (kinda like a sink).

The rest sounds good!!

Let us know what you think...Mark

You should really post a photo for better visual... crawl spaces are usually at least 16" tall which should be just enough space for 4" combination Y.
You can also come out of your clay pipe with horizontal Y, then 45 also installed horizontally, than go from horizontal to vertical with large sweep combination Y.

That condensation line from your tankless w/h can be connected to washer stand pipe, or lead it to the outside.

It is not a good practice to have 135 degree bend in toilet line...

Go my camera to work, but the picture is very bad. If you can see the picture, the stack I need to connect to is offset a little, so that is why I needed the 90 and 45.

http://home.comcast.net/~sk77/pipe.jpg

Hey Steve:

Picture helped a lot! I can see why a WYE fitting (or combo. Fitting) won't work here... ;)

In this case, I would have you install a 4" long sweep elbow (I would use 2 - street 45s glued together and then slip street end into the fernco) to come out of ground (brings horizontal pipe to vertical) then install the 4" cleanout, then install 4"x3" flush bushing (save a little more space) into cleanout, and then install 2 - 3" 45 degree fittings to OFFSET the pipe so it lines up with the vertical stack!!

Also note here, Steve that they make 3" and 4" 22.5 degree fittings that may help you to align things so things are squared up better (if underground line coming out of ground at odd angle, for example).

Good luck with it.. let us know how you make out!

Good day... MARK

Thanks for the photo...

It looks like you could cut that existing drain closer to the foundation. Can you ?
But in any case, you seem to have lots of room between drain and stack. Follow Mark's suggestion

If I was in this situation, I would insert Long Sweep Street 90 to the existing sewer, street end first. Then Bushing. Then, glue street 45 into your stack. Now, all you have left is to connect those two with on more regular 45. This 45 will fit somewhere in between those two.

Also, Home Depot sells 3" - 60 degree bends. I think they are made for this situation.

Ok... I'm back. I talked to my local inspector and he said my area follows the UCC 2006 plumbing code. With that being said, I have attached a picture of my 1st floor plumbing layout I would like to use. This was just dry fit and I do not have the slope properly set yet, but would the way I have this connected work as far as code?

Also, I forgot to check to make sure my clearances for my bathroom were code acceptable as well (stupidity on my part). What are clearances required by code for things like toilet space width, space in front of rim, bathroom door width size, etc?

I'm not sure on everything that is checked, but I do know my toilet space width is 29 1/2" wide (wall to wall) and my bathroom door width is 30".

Is there a minimum length of 3" vent pipe that is needed to stick out of the roof?

Thanks again for your help.

http://home.comcast.net/~sk77/pipe2.jpg

http://home.comcast.net/~sk77/pipe3.jpg

Steve... everything looks great! Nice job!

Minimum space for a toilet is 30" (I think inspector will let 291/2" slide... but it's close! )

30 inch door is fine (unless requiring handicap accessibility and then everything would have different requirements altogether... ;)... so hopefully, not the case here).

Vent out the roof depends on where you live. In my area we need to pipe the vent so it is between 18 and 24" (Massachusetts = snow), In Milo's area it is 12" (if I remember correctly) and in Tom's area it is 6" (Florida)... so need to check this requirement with local inspector.

Just be sure to put a STRAP HANGER every 4 feet with 1/4" pitch per foot piping and you should be all set here.

YOU did check to be sure that WET VENTING is allowed in your area...yes?? Confirm this please??

Again, great job! Keep us posted as you go.

MARK

Hello Mark,

Thanks for your reply. Yes, inspector says wet venting is allowed with 2" vent. I will check with him on the distance of vent through roof. Thanks again for all your help, I will keep you posted.

- Steve

Quote:

Originally Posted by massplumber2008

Steve...everything looks great!! Nice job!!

Minimum space for a toilet is 30" (I think inspector will let 291/2" slide...but it's close!!)

30 inch door is fine (unless requiring handicap accessibility and then everything would have different requirements altogether...;)...so hopefully, not the case here).

Vent out the roof depends on where you live. In my area we need to stick it oit between 18 and 24" (Massachusetts = snow), In Milo's area it is 12" (if I remember correctly) and in Tom's area it is 6" (Florida)...so need to check this requirement with local inspector.

Just be sure to put a STRAP HANGER every 4 feet with 1/4" pitch per foot piping and you should be all set here.

YOU did check to be sure that WET VENTING is allowed in your area...yes?? Confirm this please???

Again, great job!! Keep us posted as you go.

MARK

Oh, yes, that 60 degree bend - who would ever thought it will fit in so well..! And how about those street 45? :-)

Good job..

Yes, yes, yes... I thank you very much as well. Those fittings did fit nice :)

I was planning on connecting the laundry standpipe (for tankless waterheater) directly to the 3" stack with it's own vent, but would I be allowed to connect it via 3" x 2" WYE between the toilet and the fitting marked "To Toilet" in this picture?

If so, would I still need a separate vent for this standpipe?

http://home.comcast.net/~sk77/pipe2.jpg

Quote:

Originally Posted by Milo Dolezal

Oh, yes, that 60 degree bend - who would ever thought it will fit in so well... !? And how about those street 45 ?! :-)

Good job... !