Winter is Near: Bring on the Heat!

I started installing over 1,000 feet of Sappy Ipe in my home in November of 2011. It was a very warm fall in Omaha, and it had barely gotten below freezing up until right before Thanksgiving. I’m a wood floor “expert,” so I understand the basics of wood floor acclimation. I brought the floor in to my home about three weeks prior. I cross stacked all the wood and took moisture readings every few days.

This particular wood floor was special. We knew the moisture content of the flooring was high: it was reading 11-13%. It was an experimental load from a manufacturer that produced ipe decking. They didn’t have experience with the milling tolerances and drying requirements of indoor flooring. The floor had been stateside for about 10 months though, and had been in our warehouses for 6 months. Flooring just has a hard time drying out stacked tightly and wrapped in shrink wrap, so the floor started dropping in moisture content once I brought it into the house.

After a few weeks of acclimation, my wife decided it was time to install. I managed to stall for another week, and got the flooring down to 8.9%.

I was cringing as I began to rack out the floor: a little incredulous that a floor that acclimated this long, and had been in our warehouse for so much longer could still be this high in MC. I still knew in my heart of hearts: this floor was not ready for installation.

God does have a sense of humor, and I believe that he gave me this experience to share with you. I finished that installation with the windows of my house open, the weather warm and the floor as tight a as a tick (whatever that means).

Just as I completed my last coat of Loba Supra Satin finish (shameless plug), the weather turned cold. The windows were shut, the heat turned on, and I was thankful that I was able to sand the floor with the HVAC off. Now that the floor was finished, I was fine with things turning cold.

Would you believe that my Ipe floor started gapping within 12 hours of turning on the heat?

The floor that took 3 weeks to acclimate down to 8.9%, took less than a few days to go down to 6.5% after it was installed. I finished the final coat one evening, and came back 12 hours later in the morning and saw a gap in my kitchen. Within a few days, I was buying a new humidifier for my furnace. Within a week I was resolved to having to resand this wood floor. The gaps were too widespread and even a few boards had dry cupped. What on earth had happened?

In the next post, I’ll talk more about how winter heating cycles create the driest conditions in homes world-wide. We’ll discuss why this occurs and how to alleviate the problem.

But for now, you should know this: my floor shrunk because winter happened. Winter is one of the biggest foes to your friendly wood floor.

I’m sure you’re wondering what I should have done differently to have avoided this issue. Looking at it from the surface, you would think I did everything right: I acclimated the flooring for over three weeks. I cross stacked and encouraged air flow. The floor was aged, my HVAC systems were functioning, I had a whole home humidifier.

In truth, I had made many mistakes:

I rushed installation. Three weeks of acclimation sure doesn’t sound like a rushed installation, but ipe is a very stubborn foe. I knew I hadn’t acclimated the flooring to the “average living conditions of the home.” Nebraska winters are very cold, and when the heaters are going hard and long, the house will get dry. In the next post, we’ll talk about how dry, but suffice to say, my humidifier wasn’t going to completely correct the difference, and floor told the story.

I didn’t acclimate proactively. It’s important to understand that acclimation doesn’t have to be a passive exercise. You don’t have to simply bring the flooring into the home and let it sit. I knew that my wife wanted me to get the floor installed before Thanksgiving. That meant I needed to install fans to encourage air flow. The average living conditions of my home would be about 70 degrees and 40% Relative Humidity (RH). According the NWFA water and wood table, that mean my floor needed to be at around 7.5%.

But I also knew that Ipe’s worst shrink period is in its initial dry down. What that means is that ipe is actually relatively stable after it has reached its lowest moisture content. But the first time it drops in moisture, it will shrink considerably. To avoid winter gapping, I needed to acclimate the flooring down to its lowest level it would reach, and then let it acclimate back up to normal for the time of installation. That would require dehumidifiers to get the flooring dried down.

My last mistake was wishful thinking. I knew I’d probably have some issues. I needed to trust my experience and knowledge.

In this particular case, I was clearly at fault in the flooring installation. In a real world case, nothing really changes. If the moisture content of the flooring was high at installation: whether within the normal 6-9% range or out of the range, the installation decision is the responsibility of the installer. It is his job to evaluate the jobsite, the flooring and to determine readiness for installation.

This is the first in a series on wood flooring in the winter. Read part two and part three here. Bryan is the regional manager for our Northern store locations and has been with The Master’s Craft for 10 years.

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