Underslab plumbing mock-up

[wwhitney]

Put the lavatory above the kitchen sink on riser 2, which is the natural height order anyway, lavatory stub-outs should be higher than kitchen sink stub-outs. That order works for the UPC if the vertical pipe in between the two fixtures is 2".

Cheers, Wayne

 

[Jeff H Young]

Actually I think he has a 3 inch stack but thats pretty much correct as a lav could probebly be around 21 high 2 compartment sink way lower

 

[Sponsor]

 

[Gundraw]

Okay, looks like I am ready. Last question: I was told that the arm that goes out to the closet bend should be "nearly" flat so that my 4" riser can come out the ground vertically. I was told this was more important with modern low flow toilets.

Well, in addition to the small amounts of angle variations in my risers, I also found that my pipe going to my closet flange is around 3/8"/ft of slope.

I am considering rebuilding the assembly to not only fix the errors in riser angles, but also get this closet flange closer to flat. Any input?

 

[Reach4]

1. Consider a 4x3 closet bend (closet elbow) to make the turn, if the angle is right for you.

2. There are compression toilet flanges that don't get glued on. Getting the height right could be easier that way. The flange should go atop the finished floor. Prefer a flange with a cast iron or stainless steel ring. You need to get glued closet flanges right the first time.

3. 3/8 inch per ft or steeper is not a problem per se. However, yes, having the pipe out of the floor vertical is what you want. You can use two 45s to get the riser pipe vertical, while accommodating steeper drops in the horizontal pipe.

 

[Jeff H Young]

Okay, looks like I am ready. Last question: I was told that the arm that goes out to the closet bend should be "nearly" flat so that my 4" riser can come out the ground vertically. I was told this was more important with modern low flow toilets.

Well, in addition to the small amounts of angle variations in my risers, I also found that my pipe going to my closet flange is around 3/8"/ft of slope.

I am considering rebuilding the assembly to not only fix the errors in riser angles, but also get this closet flange closer to flat. Any input?

Dont rebuild anything 3/8 inch fall is fine it dosent have to be" nearly flat" its a 2 ft piece of pipe with what a 1/4 inch more fall than what the book says its good forget about it. riser angles a piece of plumbers tape or cut it off close to slab and glue a coupling on hold pipe plumb wahile glue sets up! Good luck

 

[Daniel Collick]

Not sure. I think discharging the kitchen sink into the vent for the lavatory may not be acceptable vertical wet venting of the lavatory.

Reach4 is right. If your drawing doesn’t specify, just make sure to use a 2” x 2” x 1-1/2” x 1-1/2” double fixture fitting and not a sanitary cross. Depending on the distance from the double fixture fitting to each fixture, as long as the total length of your trap arms don’t exceed 3’6” horizontally, you can install that double fixture fitting at a rough in height that will work for both, no lower than 16” from the floor. We usually rough labs in at 18” but that’s nothing a tale piece extension can’t take care of. It’s more important not to end up too high for a utility or kitchen sink.