I live in a 37-year old, one-story, flat-roof home in Baltimore, Maryland. The soft copper pipes under the slab have developed pinhole leaks, and I need to repipe the entire home. One plumbing contractor recommends running the main plumbing lines in a 3-ft trench around the entire home, drilling through the slab as needed to bring lines in. Another plumbing contractor recommends running a PEX system in the ceiling. What are the pros and cons of each approach? My primary concern is the pipes freezing in the ceiling.

What's the frost line in your area? How deep does the ground freeze in the winter?
Back to you, Tom

Around 16 inches. Contractor is suggesting a 36 inch trench. Thanks Tom!

I would opt to run the new water lines exposed in the house, then box around them accordingly. Keeping all water lines inside the home is the best bet here. Run them in corners, etc and then cover them up however you choose.

If your attic is closed off and not vented to the elements then It will be heated a bit from the downstairs and won't freeze the pipes. I agree with Lee. Good luck, Tom

It is a mess to repipe entire house sitting on slab. But do it. Do not put any pipes in slab again . Run new pipes through inside the house ( attic, ceilings, walls or create soffits ). It is worth it. Also, do PEX system. Let us know, how you did. Best. Milo

Thank all of you for your input. We are going to try to keep all the pipes in the house (walls, soffits, etc.) and only go in the ceiling if absolutely necessary. Thanks again!

Let us know how you make out, Good luck, Tom