Wood changes size and shape as the moisture level in the wood changes with changes in humidity. No finish can stop it, no fastening can stop it. See Chapter 3 of the USDA Wood Handbook linked below for th edetails. Figure 3-3 shows the changes in shape. Note that it depends on how the wood was in the log. Flat sawn wood tends to cup. Quarter sawn wood does not. Both have very different 'grain' patterns. Here is a link that might be useful: Wood Handbook, Chapter 3

Thanks everyone for taking the time to reply to me. That night after I posted I started putting the planks in against the very narrow floor between the wooden floor of the dining room and the peninsula. My DH and I attached 1/8 strips along the noncabinet walls and behold it clicked. Literally! After dancing up and down with delight after the first two rows were put in DH went to bed. I stayed up and was able to finish 2/3 of it by knelling on the finished end after I angled it in place and then tapping it in. We ended up having to order more boards and will finish after they acclimate to the room. I left a few of our "old boards" to mix in with the new. We ran short because we'd cut boards for the first round and they don't fit into the new layout. The floor that is in is sooooo soft on the feet. I love the feel of it. We are dog-sitting this weekend and will find out how the floor holds up to LouLou a very active young dog.Thanks again!!

Hi this is Bee's hubby. We installed ours as a DIY project and it was a bit tricky. Here is what I remember we did to make it work: - It is an issue if you start at a location that isn't solid. We "floated" the floor off of a wall but used hard wooden spacers to hold the cork out a little from the wall. Can you tack down strips to hold the cork in place and keep it from moving? This is important because you need to tap HARD to get subsequent rows to click together. - We actually had three people working on this at times because it was just easier. One person picked out the piece of flooring and laid it in place for us. Then we had two people stand or kneel on the installed pieces so they wouldn't move as the third person tapped the new piece in place. - We put the long side in by angling it at about 20 degrees, and tapping it into position. Then we laid it down flat and it would usually click in tight. We then tapped the piece sideways until it snapped in on the short side. When you do this a couple of times you get the hang of it. - Make sure your tapping block lays flat against the piece of flooring so the flooring doesn't get damaged. We had one made of MDF from the flooring company, but it started breaking apart and we replaced it with a hard plastic one from Home Depot. We also had an extension bar (looks like a flat wrecking bar) that was used to tap when you couldn't get the hammer into the right position. Hope this helps. We worked pretty hard to put our floor in but we absolutely loved it once it was done.

If, your flooring is cupped. You need to get your basement RH level down. It needs to be lower than the level above. Usually between 30-35% RH. Otherwise, your subfloor will not dry out. If, the above level is around 35% or lower. Try increasing it to 40%. As jfcwood mentioned, the bottom of your floor boards has a higher moisture content causing the base of the floor boards to expand. In order to shrink it, the RH level needs to be lower along the base of the floor boards. Cool, wet air is a wet basement. Check sump pump wells, it can be holding water. Are you running a dehumidifier? Are you by the water? Is the cupping consistent throughout the home or is it isolated to a particular area? Are you using a diluted cleaner? Also, did the NWFA inspector take a wood moisture reading with a lignometer? The reading should be consistent throughout, cupped or not. Are you able to take a reading of the subfloor from underneath? If, finished is there a vent you can take a reading from? The reading should be within 3% of the sub-floor to be considered stable. If, it is then someone needs to be responsible for a tear out and redo. Who or what caused the moisture issue?