I understand this to be a common issue, yet I'm trying to work w/ my builder to get our pipes fixed, and wanted to make sure I have a right to force the issue - they've been dragging their feet so far, even though our house is brand new and under warranty.

Problem: whenever water is turned on upstairs, both cold and hot, there are loud ticks and pops in the pipes in several locations throughout the house for the first minute or so, then they go silent for the most part. It's been getting worse over the last several months - it's getting very loud!

The plumber who installed the pipes claimed the PVC was prone to make noise, that he could not have anticipated the mysteries of wood contraction (this would seem to be common knowledge), and/or that those who installed the insulation may have affected the pipes. I definitely feel like I'm getting the run-around.

Thoughts on exactly what the problem is, and how forcefully I should push to get it fixed?

Thanks in advance.