Thank you for your responses! I feel kind of desperate. To answer your replies... This is an older structure so we can assume there is no vapor barrier in place. When the problem first occured we removed some boards and found the concrete to be drier than the air's RH and wood (where it buckled)... We had one installer and the one supplier's rep that came out, they said prior to pulling up a buckled plank that they were willing to bet that there would be a large trace of water moisture underneath -- which was absolutely wrong. There was nothing and the concrete was tested immediately and shown to be dry (they did the testing)... using a moisture reading device that was driven into the top of the wood and concrete (separately). Interesting to hear about expansion, esp along the width of the engineered planks. How would you go about adding expansion joints?? Could they be added to the field?? Recall, this is a glue-down floor. The installer keeps saying "no" because it is tongue & groove... but what does that matter if it is glue down? Are there special saws for cutting expansion joints into a slab? Two of the open space rooms are large with almost 40 ft across the width (perpendicular to the direction of the planks).

Hi, I live in Ca. I had a problem with the moulding on the kitchen cabinets. The moulding was nailed to the cabinets and showed a gap at the ceiling. I found on the internet that truss cielings and roofs expand at different rates than stud walls. My cure for the ceiling gap was to replace the moulding and secure the new moulding to the cieling and let it float on the cabinet. The problem was solved. It may Work for you. Good Luck Woodbutcher

I Googled acacia lumber and got several hits. Below are the most reliable ones. http://www.almquistlumber.com/westcoasthardwoods.html http://www.gilmerwood.com/Gilmerwood%20Stock.htm http://www.woodfirst.com/prices.htm http://www.globalwoodsource.com/ACACIA-WESTERN-BLACK.php

This is solid wood paneling, installed when the house was built in 1939. It's not over sheetrock. When I renovated, I added insulation and new HVAC systems, and replaced most of the ductwork. I need to measure the indoor humidity. I have no mold in this house. During the renovation, much of the electrical and some plumbing had to be replaced, so it's undergone many inspections. The worst expansion is in the TINY powder room, which has a regular heat vent, and is the warmest place in the winter and coolest in the summer. Because it's in a tiny hallway, the door can't be left completely open because it would block the hallway. I always leave it open about six inches when not in use. The lower wainscot in the dining room has inset panels that "float" within the framing--they're not nailed, so that was built to float during temperature and humidity changes.