New floor popping loudly in middle of night

Q: My question is related to your posting on “popping” or “cracking”, wood floor popping sound Q&A.

In my 2nd fl bedroom I recently replaced the old carpet to hardwood floor (not the pre-finished kind). We have, several times, been awoken by the loud popping sounds from the wood floor around 2-4 AM. What is the cause of that? Could it be the old sub-floor is very thin? When we walk on it, we don’t hear any noises. Thank you for your help.

A: My guess, especially since it is a newer floor is that it is moving slightly according to changes in humidity in the house. Especially when the fit of the tongue and groove are a tight fit noises like popping sounds could be heard. This should stop in time. Try to control the humidity levels in the house.

Similar Q: On the 2nd floor of my house I recently had the hardwood flooring replaced with new. Now when I walk in a room the entire floor crackles like breaking ice. If I walk around a few times it will stop for a while. At night I can hear it pop even though no one is walking on it. What is wrong and how can it be fixed?

A: Did the installers acclimate the flooring before installing? It sounds like there is some movement happening. If the milling of the tongue and grooves is particularly tight as the floor contracts it can make such noises. Try to control your humidity levels. I would think given some time the floor will settle down. Unless it starts to cup or buckle I would consider it a temporary annoyance.

Another Similar Q: We recently moved into a home and refinished the hardwood floors which had been down for 5 years. Spring has come (in Sydney) and the floors are now starting to pop and separate at some of the seams. Could this be caused by the refinishing?

A: It sounds to me that the wooden floors are simply reacting to changing environmental moisture levels in the home. Wood can and does release moisture that is in the air. If it is very dry the wood can shrink. Solvent based top coats generally allow more film stretch than water born urethanes. The popping may be the sound of the finish cracking at the joints from board movement. Perhaps you can add humidity to your home.