We purchased oak wood planks and had them delivered to our cabin in March of this year and we installed it ourselves in April. The foundation is cinder block over a crawl space (dirt). The sub-flooring is OSB and we put down a layer of tar paper. The wood flooring is nailed down. This is a cabin in the Ozarks and we only visit every 3 months. We received a call from our contractor that is doing another job and he told us that the floor has buckled. We are assuming that the high humidity of the many rains and warm weather caused this. The obvious problem is that there was no dehumidifier or a/c on during this time we were not there. Now what do we do? 
