Q: Can water popping cause cupping? Out Southern pine floors were installed and sanded. Then they water popped the floor to apply stain, which ended up looking very good. Sadly the floors looked cupped almost right after the finish was done. Since the process between the installation and finish was so quick, I’m not sure if my cupping is caused by the humidity in the house/crawling or if there was something wrong with the staining process.
A: I water pop hardwood often, especially when working with darker colours. I never do so with soft woods simply because it can take much longer to dry and because the wood is soft, I don’t feel I need to water pop soft woods to achieve the desired colour.
Having said that, I don’t believe there is much chance water popping could cup your floor. Water popping is simply wiping the surface of the floor with a wet cloth to make sure all the surface is wet, not soaked. How did they wet the floor?
Are there a lot of significant gaps between boards? I ask this because cupping occurs when there is an imbalance of excessive moisture coming up from the bottom of the board. Crowning (the middle of the board is raised higher than the edges) occurs when it is the surface of the floor which has received excess moisture. So, unless they really soaked the floor and water was able to seep between boards to the sub floor I don’t see water popping being an issue.
Likewise, and again depending on gaps between the boards, if they used a water born finish and applied several coats on the same day I could see that potentially causing a problem. It seems unusual for pine to cup. I’m not sure I’ve ever seen it happen. But it is not unusual for it to suffer significant shrinkage after being installed.
What is beneath this floor? If it is a crawl space that is damp, wet or humid that would be my first suspect.
A couple of additional questions. Was this pine left in the house for a time, say a week or two before being installed? Do you know if they happened to check the flooring and the sub floor with a moisture meter before installing? Do you live near a significant body of water, say the ocean for example? In such cases acclimation of wood to the environment takes on even greater importance.
Follow-up Q: Thanks for your answer. There are pretty much no gaps in between boards, all boards look pretty tight together. Was there supposed to be a gap between boards at installation? if so, how much? I saw the water popping process and they didn’t use much water so now I’m thinking the installation was done incorrectly or my crawling space is too humid.
To answer your other questions. I don’t live near the ocean or lake. The floors were in the house for a couple of weeks before installing. They didn’t not check the humidity of the floors and crawling as far as I know.
Here are a couple more details to narrow it down: The floors were installed in North Carolina in December and the house was vacant at the time with construction going on so the heat wasn’t running very high during the process. Maybe between 55 to 65 degrees. My crawl space doesn’t feel particularly humid. What is the ideal humidity for the crawling space and floors to be back to normal state? Once again thank you for your time.
A: Some gapping would be expected as normal. Great if you have little to none. This is not caused by water popping. I would focus on the crawl space. Have you had the installer come back to check these things out?