It is "normal" for both plastic and copper pipe (normal to expand and
contract) . The question is how the pipe was mounted and secured. Properly
done there is little noise. The question is what is properly done.
While it is possible to eliminate almost all such noise, I don't believe
I have ever seen a home built to that standard. Most people just live with
a little to avoid the large expense of doing it better.
Most of the time when there are complaints it is do to the pipes being
too tightly clamped. The pipe needs to move as it expands and contracts.
Loosing the clamps and many adding some rubber wraps may take care of a
problem, if you can get to it to fix it.
I suspect it should have been done a little better and been a lot
quieter, but I doubt if you are going to be able to get them to fix it if it
means breaking into the walls to do it.
Joseph E. Meehan
26 + 6 = 1 It's Irish Math
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