CUPPING AND GAPPING OF HARDWOOD FLOORS
Wood is a hygroscopic material. It responds to humidity levels by expanding and contracting. Wood should be allowed to acclimate to the environment it will be installed in. Wood should be installed in an environment that is kept between 40% and 60% RH. Failure to control the humidity or moisture content while installing hardwoods can result in charge-backs due to cupping and gapping.