I had approx 1500 sq ft of brazilian walnut installed in my home located in Denver, CO. I had just purchased the house and was having the hardwoods installed prior to moving in. The installer laid out the wood for 3 or 4 days to acclimatize properly and assured me that at the end of this period we were good to go in terms of moisture level of the wood.

The wood was installed and an oil-based sealer was used. To mitigate the smell the I opened the windows. Overnight, with the windows opened, the temp dropped causing some condensation on the floor in the morning.

Now, 6 weeks after the installation I have gaps forming - not necessarily big but noticable - between just about every plank. When discussing this with the installer, I was told that due to the furnace running there would be contraction due to the dry air from the furnace and that this was normal. He has also said that the wood may have been "shocked" due to the temp change causing the gaps now?? Has anyone heard of this type of "shock"? To me, if the wood was dry (ie, low moisture) and then the temp change produced the condensation I would have expected buckling to occur due to excess moisture levels not the reverse and have gaps form!! The installer had said to wait until the spring to see if the gaps resolve themselves once the furnace is turned off.

Does the explanation I received seem reasonable or should I be worried that my situation is probably the result of the wood not acclimatizing properly??

Thanks for your help.

It is normal for solid wood flooring to shrink during the heating months (winter) and then return to normal during the non-heating months. I suggest you allow the floor to go through a few seasons and see what happens.

Shock - the boards swell. this pushes on each board. Then the conditions that cause the floor to swell, have changed to a drier condition. now you have gaps.

If it popped a dew point inside your home(condensation) you had a lot of moisture in the air!!! Now you have the heat running and it is pulling that moisture out of the air. The wood will shrink.

I suggest to wait till summer and see if the gaps close up, as the wood gains back the moisture it has lost during the heating season.

Gapping in six weeks? Tell us what is different between today and 6 weeks ago. Was the home heated prior to installation? was the home heated during installation?
Is the interior climate the same now as when the floor was acclimated and installed?
If there are no seasonal changes since installation, why is there "seasonal gapping"?