[David M]

Hi All,

The drains of my two storey home drain to one point at my basement ceiling, and then vertically to the basement floor via a 3" DWV pipe to a 4" sanitary tee that horizontally provides 1) a clean-out and 2) drain to the septic out the foundation wall. The center-line of the 4" sanitary is 9" off the floor.

I wish to add a basement toilet and sink within 3 feet of the drain, and tap into the drain. I've found a wall-mount rear-drain toilet with a 3" drain whose center-line can be 10" to 14" above the floor. (Geberit pressure assist toilet with in wall tank and carrier). So, I reckon I should be safe with the toilets drain slope to the main drain line mentioned above; eighth inch of slope per horizontal foot. However, this would require replacement of the drain's sanitary tee with a double connection.

To make this work, I'll need to replace the existing 4" sanitary tee with a horizontally mounted double connection; using either a double sanitary tee, double combo wye with eighth bend or double wye. I'd run the existing house 3" drain to one side and the basement's new toilet/sink drain to the other side. I'd run the 3" drains against the wall and come away from the wall to connect to the double connection -- I hope you can visualize this ugly looking thing from a top view; basically, both 3" lines run along the wall and then come way from it far enough to connect into each side of the double connection that comes away from the wall. Therefore, a double wye or combo wye would require more "looping" away from the wall to make the connection than a double sanitary would require.

Two questions:

1) Should I be concerned with going with a double sanitary tee, rather than a double wye or double combo wye? I'd prefer the smaller foot-print of the double sanitary tee, but I'm worried that the flow of the 1st & 2nd floor drainage coming into the tee on one side will affect the new toilet/sink drainage (e.g. traps) on the tee's opposite side.

2) I'm certain I'll need to vent this configuration. Yes? I'm thinking my best option would be an AAR.


Thank you for you thoughts,

David

[speedball1]

Hi All,

The drains of my two storey home drain to one point at my basement ceiling, and then vertically to the basement floor via a 3" DWV pipe to a 4" sanitary tee that horizontally provides 1) a clean-out and 2) drain to the septic out the foundation wall. The center-line of the 4" sanitary is 9" off the floor.

I wish to add a basement toilet and sink within 3 feet of the drain, and tap into the drain. I've found a wall-mount rear-drain toilet with a 3" drain whose center-line can be 10" to 14" above the floor. (Geberit pressure assist toilet with in wall tank and carrier). So, I reckon I should be safe with the toilets drain slope to the main drain line mentioned above; eighth inch of slope per horizontal foot. However, this would require replacement of the drain's sanitary tee with a double connection.

To make this work, I'll need to replace the existing 4" sanitary tee with a horizontally mounted double connection; using either a double sanitary tee, double combo wye with eighth bend or double wye. I'd run the existing house 3" drain to one side and the basement's new toilet/sink drain to the other side. I'd run the 3" drains against the wall and come away from the wall to connect to the double connection -- I hope you can visualize this ugly looking thing from a top view; basically, both 3" lines run along the wall and then come way from it far enough to connect into each side of the double connection that comes away from the wall. Therefore, a double wye or combo wye would require more "looping" away from the wall to make the connection than a double sanitary would require.

Two questions:

1) Should I be concerned with going with a double sanitary tee, rather than a double wye or double combo wye? I'd prefer the smaller foot-print of the double sanitary tee, but I'm worried that the flow of the 1st & 2nd floor drainage coming into the tee on one side will affect the new toilet/sink drainage (e.g., traps) on the tee's opposite side.

2) I'm certain I'll need to vent this configuration. Yes? I'm thinking my best option would be an AAR.


Thank you for you thoughts,

David

Hi David,

I realize that you can see this lay out in your minds eye but you confuse me when you say you wish to replace a single vertical sanitary tee,( sounds more like a clean out tee to me) with a double horizontal combo or sanitary tee laying on its side. Let's get some terms straight before I start asking questions. Looking at a upright combo or tee the side opening is called a branch while from top to bottom is called the run.

As I understand it you're going to connect the existing 3" house main to one side of a branch of a double combo or tee on its side and pick up the new toilet and lavatory from the other side. That leaves both ends of the run open. What am I missing here? Can you make a drawing that you could E mail me? My addy is; [email protected] Regards, Tom

[David M]

Hi Tom,

You are kind for replying so quickly.

I figured any description might be troublesome. I have a digital photo I'm uploading, and a sketch of what I'm trying to do. I'll send them to you, and attach them here.

You do have it right when you say "... connect the existing 3" house main to one side of a branch of a double combo or tee on its side and pick up the new toilet and lavatory from the other side. That leaves both ends of the run open. "

One end of the run is the clean-out, and the other immediately passes through the basement wall to the septic tank.

Any clearer?

David

[speedball1]

Hi Tom,

You are kind for replying so quickly.

I figured any description might be troublesome. I have a digital photo I'm uploading, and a sketch of what I'm trying to do. I'll send them to you, and attach them here.

You do have it right when you say "... connect the existing 3" house main to one side of a branch of a double combo or tee on its side and pick up the new toilet and lavatory from the other side. That leaves both ends of the run open. "

One end of the run is the clean-out, and the other immediately passes through the basement wall to the septic tank.

Any clearer?

David

Thanks David

I'll look for the pictures. In the mean time how do you plan to convert the 3" vertical house drain to a branch of a horizontal double combo? Cheers, Tom

[David M]

Hi Tom,

To move the existing vertical branch pipe to the side of the horz. Double combo, I would extend/reduce the branch's higher horizontal portion to bring the vertical portion down to the side of the existing location.

I've sent you a drawing... sorry for the mind bender.

David

[speedball1]

Hi Tom,

To move the existing vertical branch pipe to the side of the horz. double combo, I would extend/reduce the branch's higher horizontal portion to bring the vertical portion down to the side of the existing location.

I've sent you a drawing... sorry for the mind bender.

David

Good morning David,

I can find no fault with your basic layout,( nice drawings) however a few suggestions. Use a short sweep at the base of the 3" house drain. Increase the pipe size of the lavatory drain to 2". If you can not vent to the roof a spring loaded mechanical vent off the lavatory's acceptable. I can't see any advantage to using a combo as against a DWV sanitary tee to exit the house. Go with the tee. Good luck, Tom

[David M]

Good morning Tom,

Thanks for the encouragement and advice. I've attach the diagram here, but the resolution is not good because of having to reduce the file size to fit within this site's limits.

If you have a moment, can you clarify a few things?

I've not heard of a "spring loaded mechanical vent". I'll look into it. Would a separate vent for the toilet be needed? If not, why?

Why use a short sweep at the base of the 3" house drain? Are you assuming 90 deg? Is a "short sweep" less than a standard? (I'm thinking you make this suggestion because the short sweep has a smaller "foot print" than a longer sweep, and a longer sweep would not further improve drainage because the head of the vertical drop in the drainage has plenty of power.)

Am I correct in understanding... in using a horizontal double sanitary tee, you think the 3" house drainage from one branch will 1) not negatively affect the house's drainage passing from the branch into the run of the tee, and 2) not negatively affect the trap of the opposite branch's new toilet.

Cheers,

David

[speedball1]

Good morning Tom,

Thanks for the encouragement and advice. I've attach the diagram here, but the resolution is not good because of having to reduce the file size to fit within this site's limits.

If you have a moment, can you clarify a few things?

I've not heard of a "spring loaded mechanical vent". I'll look into it. Would a separate vent for the toilet be needed? If not, why?

Why use a short sweep at the base of the 3" house drain? Are you assuming 90 deg? Is a "short sweep" less than a standard? (I'm thinking you make this suggestion because the short sweep has a smaller "foot print" than a longer sweep, and a longer sweep would not further improve drainage because the head of the vertical drop in the drainage has plenty of power.)

Am I correct in understanding... in using a horizontal double sanitary tee, you think the 3" house drainage from one branch will 1) not negatively affect the house's drainage passing from the branch into the run of the tee, and 2) not negatively affect the trap of the opposite branch's new toilet.

Cheers,

David

Hi David,

When you said in your first post you were going to vent with a AAR I thought you meant AAV,(air admittance vent) which is a mechanical vent used in installations where a vent through the roof isn't practical. To check these out click on; http://www.studor.com/homeowners.htm
The toilet will be wet vented through the lavatory vent and should not require a separate vent.

You asked," in using a horizontal double sanitary tee, do you think the 3" house drainage from one branch will 1) not negatively affect the house's drainage passing from the branch into the run of the tee, and 2) not negatively affect the trap of the opposite branch's new toilet. " I wondered about that but your layout doesn't allow for any other setup. However may I make a suggestion? Since you have a pressure assist toilet I don't think the back pressure caused by a gravity swing check valve would hinder the flush action, ( check this out with Gerberit and let me know what they say).
I don't see a problem with any discharge backing up in the lavatory since the tee is installed above the level of the toilet branch. Is your layout iffy? Perhaps. Do I wish you would go back and configure it differently. Yes I do. But with what you wish to accomplish you have configured it the simplest way it could be done. Good luck, Tom

[David M]

Thanks Tom. I respect your thoughts and time, and I don't mean to be too much trouble. We are finishing our basement to make space for our 5 young kids, and I'm hoping to include this toilet/sink.

I'm in the planning stages, so suggestion of a better arrangement is possible. I have 1) the existing drain, as shown in the diagram, 2) limited floor/wall space that will allow for a toilet on the one side and a sink to the other and 3) concrete wall and floor. I'm planning on adding a 6" stud wall to the foundation wall to support a wall-mounted rear-drain toilet.

Concerning the vent...

1) I mistyped, as I ment an AAV (air admitance valve) as you mention. I've found that the Studor AAVs seem to be the most accepted by municipalities, so I'm comforted by your suggestion.

2) I'm familiar with a "wet vent", but I was not sure a wet vent could be considered through a DWV double sanitary tee and the house drain between the toilet and and lavatory with AAV.

Regarding the house drain branch affecting the new toilet branch... I'm not sure I have the space for the 9" length a 3" check-valve would require. I'll have to see.

If you have a suggestion for a different configuration, please feel free to share it. In the mean time, I may get a measurement of the distances I have to play with on either side of the existing drain.

Cheers,

David

P.S.: Thanks for your "closet bend" response.

[speedball1]

Thanks Tom. I respect your thoughts and time, and I don't mean to be too much trouble. We are finishing our basement to make space for our 5 young kids, and I'm hoping to include this toilet/sink.

I'm in the planning stages, so suggestion of a better arrangement is possible. I have 1) the existing drain, as shown in the diagram, 2) limited floor/wall space that will allow for a toilet on the one side and a sink to the other and 3) concrete wall and floor. I'm planning on adding a 6" stud wall to the foundation wall to support a wall-mounted rear-drain toilet.

Concerning the vent...

1) I mistyped, as I ment an AAV (air admitance valve) as you mention. I've found that the Studor AAVs seem to be the most accepted by municipalities, so I'm comforted by your suggestion.

2) I'm familiar with a "wet vent", but I was not sure a wet vent could be considered through a DWV double sanitary tee and the house drain between the toilet and and lavatory with AAV.

Regarding the house drain branch affecting the new toilet branch... I'm not sure I have the space for the 9" length a 3" check-valve would require. I'll have to see.

If you have a suggestion for a different configuration, please feel free to share it. In the mean time, I may get a measurement of the distances I have to play with on either side of the existing drain.

Cheers,

David

P.S.: Thanks for your "closet bend" response.

Why not configure it this way. A 3 X 2" sanitary tee mounted 17 3/4 off the floor to center,( of the branch) on the 3" house drain to pick up the lavatory going to a 3" short sweep at the base. Then a 3" sanitary tee on the lateral, (horizontal line) to pick up the toilet and last a 3" sanitary tee with a cleanout mounted in the hub to connect to the sewer.
That way you wouldn't get the discharge from the house drain shooting directly into the toilet. Sound like a plan? Regards, Tom

[David M]

Hi Tom,

Great minds might be thinking alike... last night I figured I have enough rom to put two 4x4x3 sanitary tees together along their runs, and connect the branch from the house drain and new sink into one tee, and the new toilet into the second. The outermost one from the wall would include the clean-out, while the innermost would go to the septic. As an alternative, I could use a 4" combo and 4" sanitary tee together along their runs, the combo would bring in the house branch from veritcal, and the sanitary tee could bring in the new adjacent toilet from a lateral branch.

Tom, is this something like what you are saying? When you suggest two sanitary tees, I cannot imagine how they relate to each other unless it is as I'm thinking. The new toilet branch must come into the 4" drain horizontally (i.e. laterally).

Cheers,

David

P.S.: It looks like Katrina safely looped around your area at a distance. Hopefully she does not cause too much damage elsewhere.

[speedball1]

Hi Tom,

Great minds might be thinking alike... last night I figured I have enough rom to put two 4x4x3 sanitary tees together along their runs, and connect the branch from the house drain and new sink into one tee, and the new toilet into the second. The outermost one from the wall would include the clean-out, while the innermost would go to the septic. As an alternative, I could use a 4" combo and 4" sanitary tee together along their runs, the combo would bring in the house branch from veritcal, and the sanitary tee could bring in the new adjacent toilet from a lateral branch.

Tom, is this something like what you are saying? When you suggest two sanitary tees, I cannot imagine how they relate to each other unless it is as I'm thinking. The new toilet branch must come into the 4" drain horizontally (i.e., laterally).

Cheers,

David

P.S.: It looks like Katrina safely looped around your area at a distance. Hopefully she does not cause too much damage elsewhere.

No, I was proposing to cut a 3 X 2" sanitary tee mounted 17 3/4 off the floor to center,( of the branch) into the 3" vertical house drain to pick up the lavatory. The 3" house drain to continue on to a 3" short sweep at the base. Then a 3" sanitary tee on the lateral, (horizontal line) to pick up the toilet and last a 4 X 3" sanitary tee with a cleanout mounted in the hub to connect to the sewer. Can you give me a drawing so I can see what your layout would consist of? We'll get a little wind off Katrina and lots of rain but that'll be about it. I'm not even bringing in lawn furniture. Wetfully yours, Tom

[David M]

Tom,

You are a patient man. Thank you for being generous with your time.

Please forgive me for being somewhat dense, but what do you mean by "sanitary tee on the lateral"? Do you mean the tee would be horizontal with the branch to the side, and the house drain would come into the branch while the new toilet would enter the run from one end with the other end entering the branch of the 4" red sanitary tee?

As for what I was thinking, attached is the duagram.

Cheers,

David

[speedball1]

Tom,

You are a patient man. Thank you for being generous with your time.

Please forgive me for being somewhat dense, but what do you mean by "sanitary tee on the lateral"? Do you mean the tee would be horizontal with the branch to the side, and the house drain would come into the branch while the new toilet would enter the run from one end with the other end entering the branch of the 4" red sanitary tee?

As for what I was thinking, attached is the duagram.

Cheers,

David

Where exactly does the 3" house drain come out next to the sewer outlet?
I have two different drawings. One shows the 3" house drain directly over the sewer,(existing drain configuration) and another shows the house drain to the right of the sewer connection, (new drain configuration). Which drawing is correct? My lay out addressed the latter offset to the right house drain. If there is a off set how much distance between the center of the 3" house drain and the center of the sewer outlet. Have I been working with the wrong layout? Regards, Tom

[David M]

Tom,

We've been at our 8 year old's soccer tournament this week, and we are very wet from all the rain -- no wind though. We'll get the rain from Katrina in a few days, as we are along its path northward.

Currently, the 3" house drain comes in from above, as in the original drawing. My original thought was to offset it and bring it in from the side of a double tee/wye/combo -- drawing also in the first set of figures. My last post and drawing were thoughts on a different configuration using two tees joined along their runs and bringing the 3" house drain in from above with one tee, and the toilet in from horizontal with the second tee.

I'm still trying to understand what you were suggesting with your post yesterday with "3 inch sanitary tee on the lateral"?

Sorry for the confusion.

Cheers,

David

[speedball1]

Tom,

We've been at our 8 year old's soccer tournament this week, and we are very wet from all the rain -- no wind though. We'll get the rain from Katrina in a few days, as we are along its path northward.

Currently, the 3" house drain comes in from above, as in the original drawing. My original thought was to offset it and bring it in from the side of a double tee/wye/combo -- drawing also in the first set of figures. My last post and drawing were thoughts on a different configuration using two tees joined along their runs and bringing the 3" house drain in from above with one tee, and the toilet in from horizontal with the second tee.

I'm still trying to understand what you were suggesting with your post yesterday with "3 inch sanitary tee on the lateral"?

Sorry for the confusion.

Cheers,

David

OK David,
Thanks for clearing that up. I hope you're on the eastern edge of the panhandle. You guys have been hammered enough by hurricanes.
I was proposing to cut a 3 X 2" sanitary tee mounted 17 3/4 off the floor to center,( of the branch) into the 3" vertical house drain to pick up the lavatory. Just as you depicted The 3" house drain to continue on to a 3" short sweep at the base. This converts the house drain from the vertical to the horizontal. Then a 3" sanitary tee looking out on the lateral, (horizontal) line to pick up the toilet and last a 4 X 3" sanitary tee with a cleanout mounted in the hub to connect to the sewer.
That way the flow would be continuous to the sewer and would keep the installation closer to the wall then the offset you show in your latest side view. The toilet would be locked into the space between the short sweep at the base and the 4 X 3 tee connecting to the sewer but the lavatory could be placed any where. Also this configuration would eliminate the extra elbo that you would need to line up the toilet installation and the less elbos used in drainage the happier that makes me. Have a great week end and stay safe. Tom

[David M]

Hi Tom,

Katrina sure did power-up fast. Holy cow. We are in the mid-atlantic states, so the rain we got this weekend is not Katrina. We'll see Katrina in a few days. I sure hope she goes further west because a hit on New Orleans and Mobile would be very bad.

Tom, for the life of me, I cannot image what you are describing. Let me know if I should get lost, as I don't want to trouble you too much. Sorry if I'm frustrating you.

I follow you until the 3" sanitary tee. Maybe answers to a few direct questions will help the image in my head:

1) Is the vertical house drain coming down to the right or left of the 4" septic line entering through the wall?

2) Where is the 90 degree short sweep with respect to the 4" spetic line? (e.g., roughly 4 inches above and 1 foot to the right)

3) Which direction does the 90 degree short sweep direct the flow? (e.g., horitontally left along the wall.)

4) Which part of the 3" sanitary tee does the short sweep's flow enter? (e.g. one end of the run)

5) Assuming answer to 4 is the run, which direction is the 3" tee's branch pointing? (e.g., horizontally away from the wall, down or up)

6) Assuming answer to 4 is the run, I assume you have the toilet coming in the branch and the run continuing to the 4"x3" sanitary tee. Yes?

Cheers,

David

[speedball1]

Hi Tom,

Katrina sure did power-up fast. Holy cow. We are in the mid-atlantic states, so the rain we got this weekend is not Katrina. We'll see Katrina in a few days. I sure hope she goes further west because a hit on New Orleans and Mobile would be very bad.

Tom, for the life of me, I cannot image what you are describing. Let me know if I should get lost, as I don't want to trouble you too much. Sorry if I'm frustrating you.

I follow you until the 3" sanitary tee. Maybe answers to a few direct questions will help the image in my head:

1) Is the vertical house drain coming down to the right or left of the 4" septic line entering through the wall?

2) Where is the 90 degree short sweep with respect to the 4" spetic line? (e.g., roughly 4 inches above and 1 foot to the right)

3) Which direction does the 90 degree short sweep direct the flow? (e.g., horitontally left along the wall.)

4) Which part of the 3" sanitary tee does the short sweep's flow enter? (e.g., one end of the run)

5) Assuming answer to 4 is the run, which direction is the 3" tee's branch pointing? (e.g., horizontally away from the wall, down or up)

6) Assuming answer to 4 is the run, I assume you have the toilet coming in the branch and the run continuing to the 4"x3" sanitary tee. Yes?

Cheers,

David

Hey David,
I made a freehand drawing that should answer your questions,(see attachment) if not click on back and I'll try to clear things up.
. Glad you're up state from the coast. Stay dry, Tom

[David M]

Tom,

You are a real techie converting a free-hand drawing to PDF.

I fully understand what you are saying. My mental block to your previous description was that I did not think the wall-mounted toilet could drain straight back into a tee. It is a 2x6 studded wall.

I see that the Geberit manufacturer offers a back-to-back discharge fitting for back-to-back closets. Maybe this is what I would use.

Thoughts?

Cheers,

David

[speedball1]

That works for me Dave,
Now the flow's all going in the same direction. Do you have a application to make your drawings or do you lay them out on a drafting board and scan them in? Regards, tom