Hardwood Floor Damage - GreenBuildingAdvisor

Hardwood Floor Damage jimbo365 | Posted in General Questions on February 21, 2026 11:15am This is at a friend’s house. The house was built in 1988. They have lived there for 15 years. The first 14 there were no issues. This year the wood flooring is tented and cupped from expansion. It’s the same flooring since 1988. We are in northern NM. It is a pretty arid climate, but we do get cold.   Now, the big difference is that for the first 14 years, the cooling was done with an evaporative cooler. This will work in a dry climate like ours, but it adds a lot of humidity to the inside of the house in the summer months. Last year the house switched to refrigerated air via mini split ductless units. This will lower the indoor humidity during the summer months.   The flooring is above in floor radiant heat. The subfloor layers are : concrete slab, Thermax insulated board, 2×4 sleepers on edge, 3/4” plywood, roofing paper and then 3/4” maple hardwood flooring. The tubing is copper, and was pressure tested for leaks with no leaks found. When the heat was turned on this winter, the flooring pushed up, cupped and generally showed high moisture issues. The flooring was cut open at one of the tented spots. The bottom of the hardwood was dry. There was water collecting on the bottom side of the felt paper under the finished floor, and above the sub floor. My theory is that when the heat was turned on, the humidity trapped in the sand was released and tried to move up towards the very dry a...