Lowering Kitchen Sink Drain Line

[morpheusmurals]

Hello,

I just installed a 10" undermount sink- used to have a 8" above. Nice surprise when I figured out the drain line was too high.

I am planning on cutting open the wall to lower the drain in the main line.

Couple questions:
Currently the main drain travels 24" horizontally connected with a Tee at the 2" main line. That 2" pipe is vented to the roof. Is that vented correctly?

Can I just open that line and do the same thing lowering it to the appropriate height? Is the Tee creating a vent? Can I use a Fernco Quick Tee to make the new connection? The line is galvanized pipe.

Do I need to slop the horizontal line downward toward the main line?

I attached a photo when the wall was open. Of course now it is all drywalled and has a nice cabinet in front.

Thanks!

[pushkins]

Yes you can cut out the existing T and add a fernco T 2" lower, you will need to add PVC pipe if you do that or I guess you could cap/plug the existing T and add the fernco below it.
Any drain line you want to maintain 1/4"/foot slope.
Yes that seems to be vented correctly.

[LazyPup]

Very easy solution here;

First pull the cabinet and open the stud bay where the existing line is.

2. Place a mark on the side of the tee where the centerline of the existing fixture arm is.

3.Measure 3" up from the end flange of the tee and place a mark. This will insure you have enough pipe for a Fernco coupling- This will be your top cut line.

4.Measure the height from the center line on the TEE to the top cut line.

5. Now place a mark on the lower drain riser at the desired centerline for your new drain line.

6. From that mark measure down equal to the length you got in step 4. This will be your bottom cut line.

Now make the two cuts, pull the pipe out and turn it upside down. The riser will now be the correct length to reconnect on both ends with common Fernco's and your fixture arm will be at the desired level.

[bettyjmaar]

That look gross