Plumbing under the sink question

Hello all, gad I found this board as I have in front of me something I’ve never seen done and am not sure if I should call a professional. I am getting new granite countertops and a new sink. The sink is 4 inches deeper than the existing one, so all the plumbing under the sinks and disposal must be re configured. It’s that silver type metal plumbing and I would like to attempt it in PVC. Can I simply put my disposal back on the new sink or would new parts be necessary to attach it to the new sink? Are there pictures or posts that have diagrams on what steps I would take. I’ve replaced and worked on my sprinkler system is the extent of my PVC experience. I’m not even sure of the questions I should ask. Any advice would be great.

Assuming you own the pipes (not a condo association) you can rework the SanTee. A thread happening today deals with something similar. It's https://terrylove.com/forums/showthread.php?t=12905

Another thread has a couple links to good diagrams: https://terrylove.com/forums/showthread.php?t=11328

That is plenty of reading for now.

David

Thanks for the links. Yes it is my house. I know the basic diagram that I will use; it’s basically the same just 4 inches lower. Can I use PVC when all the connection to the disposal is metal? How do you marry up PVC and metal pipes? The drain is low in the wall and soldered at the wall level and comes out about 16 inches. Do I cut that to accommodate any changes or do I leave it in place and work around it? That’s where the PVC would have to be joined to the metal pipes. I will need a T section for the disposal and other sink connection. Do I glue them together? How does PVC join to metal when the metal is not flanged to allow the PVC screw to tighten the fitting?

After reading the board I at least know the questions, I think. Thanks and any advice would be welcome.

Sink pipes usually have a flair on them to allow them to slip over the appropriately sized pipe, sealed with the compression washer and nut.

caleb said:

.... the same just 4 inches lower.... The drain is low in the wall and soldered at the wall level ....

Click to expand...

Tubular is the key word to use when you search the web. And 1-1/2" Use 1-1/2 as the key word, with the hyphen.

The big question not answered in your quoted text above is whether the Tee connecting the drain into the wall pipe is at the right height. You said it's low, but that may just be a beginner's view. It has to be at the same height as the end piece coming out of the P trap. Then water flows out of the P trap and into the wall pipe. A slight slight slope can be good too, something like 1/8" drop. Take another look, and you ought to see that the Tee is at the same height as the P trap's tail. Otherwise, take pictures and post them so other people can comment on what you have.

When you rebuild the same just 4 inches lower, your water coming out the P trap goes on a flat line, in a horizontal pipe, with or without that minor slope. This means you have to cut and reposition the Tee in the wall pipe, four inches lower too. This is serious; it must be done.

What you had before was chromed brass, chrome plated brass. It's good stuff, it'll work again, it'll be easy to install since it has slip joints that you turn by hand, and so I would reconsider whether or not to use this same material again.

Other people will tell you how to mate PVC to pipes of other materials. Search "tubular". You'll see PDF catalogs showing both brass and PVC, and many different adaptors and connectors.

david

You can probably extend the tailpiece off of the bottom of the sink, put on a new or replaced trap and go into the wall. Without a picture, it is hard to say exactly. The bigger problem is when the wall connection ends up higher than the new deeper sink...there, you are trying to get water to run uphill; doesn't work, clogs, drains slowly if at all.