Gaps the size of a nickel after installation

Q: We installed a 5″ select white, glued and nailed, unfinished oak. The subfloor 11%. The material 10.2% finished with stain and LNL 1500. On installation the floor was tight and now there are visible gaps the size of a nickel. Can this floor be sanded, re-hydrated, and finished? If so, what process would you suggest?

A: The moisture readings, while not outrageously high could have been a percentage or two lower, but the difference between sub floor and oak is okay. If the air is dry you could run a humidifier. It isn’t often I see a floor that is without some small gaps. And the wider the board the greater potential for increased shrinkage.

This is probably not much help, I know. But controlling the environment is one of the few things we can have some control over.

Follow-up Q: Do you think resanding the oak and adding moisture to it by spraying water – similar to popping – will close the gaps? The house does have a humidifier in the heating system. We are desperately trying not to rip this finished product up.

A: Spraying water on the surface doesn’t have a hope of expanding the planks. I don’t think anyone can ever guarantee a wooden floor will stay tight and never get any gaps. NWFA has always held to the view that a gap about as thick as a dime is normal and expected. I would suggest to the home owner they give the floors time to go through a couple of complete seasonal cycles. It’s probably going to expand a bit in the humid summer. If you have a hygrometer set it on the floor for 15 minutes to see what the moisture level in the room is. I know you can’t have humidity up over 45 RH on cold winter days. But if it is down to 30 or less, that will suck the moisture out of everything. Did you give the flooring time in the rooms to get used to the environment?

Follow-up Q: Yes the flooring was in the house for a week. The only issue with waiting is this is a new construction so the house is presently empty. I will be doing RH testing and moisture reading tomorrow.

A: I figured it was new construction. I really don’t like doing those jobs. Other contractors are crawling over each other and everything gets rushed at the end, whether it’s ready or not. Back in the early days of self employment when I had to do sub contract work, there were a lot of jobs in new sub divisions. Installation of Bruce. There was no acclimating the flooring. The last week before closing, every trade was in the place. Every rule and precaution were broken as far as flooring goes. I kept telling the builder, if this floor goes south, it isn’t my fault.

One of the worst I saw was when I lived in Niagara. I got a call to look at a floor in a sub division. It was all badly cupped. Clearly the structure was not dried out before the floor went in, and the wood swelled. The builder told the home owner the floor meets warranty specs. I couldn’t believe it.

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