I am trying to relocate my stack washer/dryer to an inside wall and would like to add a sink next to it. Will the configuration I have attached work?

I believe your configuration is nearly correct

But the line where washer drains into needs to be 36" tall

And I would tee sink in below floor to avoid water from washer

From coming up in sink -- I would run a straight pipe from the

Stack and tee down to for the washer and sink traps, and install

A cap on the end of the pipe for a clean out...

Does the stack and the vent run up on the outside of the house

-- concerned about freezing in winter months

OK.. I got the part about tapping into the line under the floor for the sink, but I don't quite understand the part about the line from the stack to the traps. You mean go higher up the stack and tee in for the venting in the attic? And yes the stack (drain/vent I installed for the washer) is outside running along the side of the house as you can see in the drawing. We don't get much freezing here in New Orleans... Just a lot of water here and there!! LOL

I am trying to think of a good way to explain this clearly

1. The pipe for washer drain needs to extend 36" above floor

2. The drain for sink should go straight down through the floor

3. Both drains need P- trap below the floor and tee into drain line

4. The drain comes into the house at a convenient level - below floor

5. For convenience a cap is placed on drain line -- clean out

Got it! Do I need any venting for the sink?

Also I forgot to mention that this is on the second floor of the house.

Is it possible to plumb it the way I suggested and build an enclosure or

False ceiling to hide plumbing, being in a living space makes a difference

Also you could run your drain line close to ceiling and put traps on upper

Level near floor -- don't think you need vent on sink