I'd like to expand my kitchen and install a pantry in the corner. In order to do that, I'd need to bump out my kitchen sink and counters by about 6-8 inches straight back into family room.

The sink/garbage disposal sits next to a dishwasher in an L-shaped counter. The sink faces the family room (and counter seating). The main drain pipe is in slab. Is it possible to bump out without cutting into slab and moving drain?

I know nothing about plumbing, but looking under the sink, it seems to me that all the p-trap and garbage disposal lines, etc., could be flipped to back side of main pipe that leads into slab. Since I'll be replacing the counter and cabinets with new ones, I could put access to the sink cabinet on back side as well as in front. (Considering removing carpet and going with tile, anyway.)

Or can it be done somehow and still maintain the p-trap in front? Or must I abandon this idea (or pay bucks to have main pipe moved via digging up slab).

  • You should be able to angle back to the original point at which the pipe enters the slab, assuming there's room in the cabinet base, but we'll need to see what you're describing. Photos, please. You'll need to host them elsewhere and link them until you have more reputation points.
    – isherwood
    Commented Jan 11, 2016 at 2:04

1 Answer 1


This should be achievable by adding a horizontal run from p trap to the drain without digging into your foundation. Horizontal runs must be downwardly sloping at 1/4" drop per 1' run to function properly.
Since it sounds like you are only moving 8 inches you shouldn't need to worry about adding a vent line. These are sometimes required by code for long horizontal runs and help vent gases allowing for smooth drainage. The p trap can be on the front or back. Doesn't matter as long as it does not become an s trap or a double p trap.

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