copper strip in corner of shower under the backerboard I am in the middle of the demolition of my old shower and have come across this copper strip in the corner.

What is this used for? I assume it is somehow supposed to prevent water damage?

1 Answer 1


Many years ago copper was the best way to seal corners and also used at the overlap on surrounds. Today we use membranes, Or thick pvc sheeting to protect the structure and keep the moisture in the shower.

  • 1
    Of course, they couldn't really have cared much about moisture because they used drywall in a shower...
    – iLikeDirt
    Oct 21, 2016 at 14:19
  • Many times green board was used a water resistant sheet rock. I have seen green board last for over 20 years in a shower. Cement board with a liner is the best way to go.
    – Ed Beal
    Oct 21, 2016 at 16:26
  • 1
    Right, cementboard is the way to go. Greenboard is better, but still inadequate and incorrect. It is still a gypsum product and gypsum turns to soup when inundated. A shower that needs to be ripped out and replaced after 20 years (likely with water damage causing rot, mold, and termite infestation) is a shower that was built incorrectly by a builder who didn't know what they were doing.
    – iLikeDirt
    Oct 21, 2016 at 17:16

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