Can a roof leak cause cupping in a hardwood floor?

Q: Hello, is it possible for a roof leak to cause cupping? For the water to go down through the walls and get under the floors? We have cupping floors and that is the only possibility for water damage. 

A: Yes it is very possible. I’ve seen that happen more than once. All I can suggest is locate and fix the leak and run a dehumidifier to dry out the floors. Once in a while they will actually flatten out. Unless you suspect a lot of water under the floor the best thing to do is leave it alone and let it dry out completely.

Follow-up Q: Thanks so much for you response. Do you have a suggestion for how often and how long to run a de-humidifier without over doing it? Thanks!

A: I don’t think you can over do it running a dehumidifier. Having a hygrometer in the home can be helpful. It gives a reading of temperature and RH in the room. This time of year an RH of 45-50 is normal. I installed unfinished oak once in a very old house in Toronto. This place was on the edge of a ravine, surrounded by trees. One day it was mid 90’s and the humidity level was over 90%. In a panic I told the home owner, who wasn’t living in the house yet, to bring a dehumidifier fast before it started raining inside the house, lol. I wouldn’t expect you to have a moisture meter but if you had one you place it on the floor and it will tell you the moisture content of the wood. 6-10% if fine. 15 and up is not good.

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