Washer Standpipe Install in Tight Space

[homewrecker]

Hello and Happy New Year!

I'd like to install a washing machine drain on the second floor of my home. The 1 1/2" drain line from the second floor bathroom sink/tub enters the main stack immediately below the proposed location for my washer. I'd like to enlarge this line and connect my washer drain to it, but the pipe is on a curve and space in the floor cavity is tight. I'd like anyone's opinion as to whether a proper washer drain installation is possible here.

In the attached diagram, I've drawn what exists and a proposal for what I think would be needed -- if it's allowed by code and common sense! The 2" P-trap for the washer standpipe would connect to the san-tee inlet shown in the second diagram.

If this should be possible, I have two other questions:

1. I suspect that the san-tee cannot be placed at an angle, only vertical. Would a Wye with a 45 degree elbow on the inlet be correct? I'd need the 45 elbow in order to make the trap plumb.

2. Is a vent needed here, given the immediate proximity to the main waste stack?

3. When the P-trap is attached (it will come outward toward us in the perspective in the diagram), it will not quite reach the wall cavity on the second floor above, where I hope to place my standpipe. Can the vertical standpipe make a slight bend with two 45 degree elbows (or sweeps, if there's room) above the trap, or must it be a straight vertical run from the top of the standpipe to the trap?

Thanks very much for your advice!

[Terry]

Waste fittings on the horizontal need to be wyes and not tees.

I don't care for the rubber fitting. Many of those over them will crimp on themselves, or allow the pipes to shift.

The p-trap for the washer can't be below the floor.
It needs to be on the same floor as the washer, with at least a 18" standpipe.
The vent needs to be within five feet of the trap, and between the wye.
Every fixture should have a vent, which helps to prevent the traps from siphoning.

[markts30]

Draw a quick floor plan with the walls shown...
Would give a better idea of that can be done regards to the plumbing...

[homewrecker]

Terry: Thanks for your response and advice. What method do you prefer for connecting lead pipe to PVC? Given that a vent is required, would creating an auxilliary stack, as shown in diagram3 (attached) be correct?

markts30: A floorplan is attached. The main stack has only one 2" inlet that is set 10" below the floor. The lead pipe turns downward at a 45-degree angle as it approaches the stack, as shown in the first diagram. It is this section to which I had hoped to add an inlet for the washer in the adjacent room.

BTW, this house is 100 years old; plumbing is at least 50 years old.

Thanks so much for your help!

[markts30]

That is better...
If the branch line is not under a wall, you could also do something like this....

[homewrecker]

An awesome illustration, markts30! Thank you so much!

One more question, if I may. Since a vent is required, my main stack has a vent inlet about 5' above the floor, which is being used to vent the toilets, which is required because they rest one above the other. The vent pipe is 2". May I join this vertical vent pipe in order to avoid having to cut into the main stack to add a vent inlet? (See file diagram4, "Proposed Arrangement 2b")

Thanks a million for your advice!

[hj]

You have to connect the vent to an existing vent point or into the main stack the proper distance above all other drain connections. Connecting to that point, given that it is a lead drain connection, is going to cause you some problems transitioning to plastic.

[homewrecker]

Thanks, HJ. The vent line show in Arrangement 2b is iron; I can add a vent T at the highest point by cutting out about 5 inches of the iron vent pipe and connecting the vent T with banded couplings.

The only lead-to-plastic connection is below the floor, where the existing bathroom drain connects to my new plumbing. What method is best for making this connection? Thanks!