5 yr. old, 3/8th's inch, 3 ply GlenCovePlank/Bruce pro glue-down on wood subfloor over foundation...popping up in two large areas so there's "give" underfoot. Is this most likely installation problem (poor subfloor prep vs. not enough glue, etc.)? Should I replace, have nailed down, or what? No moisture detected either in crawlspace or from above. Would you go after the retailer/installers if you were me? Got to make some decisions here soon.

Have it inspected by an independent certified wood flooring inspector.

www.NWFA.org

www.NOFMA.org

http://fits4.org/ilist/ilistmain.html

5 year old floor?
This is not an installation or product problem.
Something changed in the house.
SO, tell us about changes.
1. Sprinklers added to the yard?
2. Landscaping?
3. New heater/air?
4. Room addition?
5. Water get under the house at any time?
6. Exceptionally cold or hot summer?

Something changed or was added...