I was called out to do an inspection regarding a 3-inch Brazilian cherry having serious gaps. The homeowners are Minnesota snowbirds who travel south for the winter. Before leaving, they hired a flooring contractor to install the 3-inch Brazilian cherry. The neighbors came over to look it when completed and said the floors looked OK to them, and the homeowner sent the flooring contractor a check paid in full for the work outlined on the proposal—all in all, pretty standard procedure for snowbirds.
Once the homeowners returned home in the spring and saw the wood floor with gaps, they called the flooring contractor to look at the floor. He told them that heating season had just ended, so wood flooring is typically gapped then, and that the gaps should close up by the end of summer. By the middle of our humid summer, the gaps were not closing, but the flooring contractor told the homeowners they must be patient and wait for the wood floor to finish swelling before an evaluation can be made. The homeowners, as many do, got impatient and called for a wood floor inspection.
I found the gaps in the floor measured from 1/16–1/8 inch with an average of 3/32 inch. Destructive testing revealed the flooring was nailed down with the 2-inch cleat. It was also evident that the cleat was not seated properly into the nail pocket on the tongue. Further evaluation found the cleat was sitting at an angle, simply meaning the floor nailing machine was not sitting square to the plank when the fastener was inserted. This left the head of the cleat elevated enough so the adjoining plank could not be securely tightened against the next board at the time of installation.
This is a common problem when installers are moving at warp speed to install the wood floor. Also, when installing dense wood species such as Brazilian cherry, sometimes as the air pressure drops in the compressor, there is not enough psi to fully insert the cleat into the nail pocket. This is often overlooked by the installer.
Needless to say, this gapped floor was NOT caused by seasonal change—which would be considered normal—but by the installation, and it will be the installer's responsibility to replace the floor at his expense. It's extremely important to pause during installation to keep a keen eye on fasteners and make sure they are being seated correctly.