Why Kiln Dry Wood?

||Why Kiln Dry Wood?

Offering the Best Quality Reclaimed Wood for Your Home

One of the first questions we’re asked at our shop is why do we still kiln dry reclaimed wood since it has been air drying for 100 plus years. There are a variety of answers to this question but we’ll narrow it down to our two main reasons for kiln drying reclaimed wood and give a little detail into each and the process behind it all.

The first reason is pretty simple but extremely important. And, one for which our customers are very thankful. All wood, especially barn wood, can have bugs and worms living in the wood. By kiln drying all our reclaimed wood, we guarantee that none of these critters hitch a ride into your house along with the wood!

The second reason is a little more complex and requires careful monitoring throughout the kiln drying process. For any wood product that goes into a home, especially anything being glued or joined together, the moisture content of the wood needs to around 6-8 percent. This can only be achieved through kiln drying. Even though much of our reclaimed barn wood has been air drying for more than 100 years, the relative humidity in Ohio will only allow the wood to dry down to around 12-15 percent moisture. The inside of a house (especially in the winter) can become extremely dry and wood with a higher moisture content will shrink. If not kiln dried, large cracks and warping can take place. Even with kiln dried wood, we recommend monitoring your environment for best results.

How Does Dead Wood Hold Moisture?

Wood has two kinds of water in it – Free Water and Bound Water. As a cut tree or a wet beam air dries, it loses free water (the water that is freely moving in the pores). Bound water is water that is sealed (or bound) inside the cells. All this water can’t escape unless the outside environment is extremely dry and bakes the wood (hence the kiln). By drying in the kiln, the cells burst and the bound water can then escape allowing the moisture content in the wood to reach 6-8 percent.

This year we had the opportunity to upgrade operations with a kiln from Kiln-Direct and, you can see by the video below, we’re extremely pleased that we can now dry our reclaimed lumber in this massive kiln! With a little help from our friends at JCrane we were able to get this wide load set into place. We’re currently running a drying cycle every 2-3 weeks as this new kiln has the capacity for 9,000 board feet.

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Depending on the wood species, thickness and how old the wood is determines how long the wood needs to kiln dry. For most reclaimed material it is about a 5-6 day turnaround. For new growth lumber it can be up to 3-5 weeks. The goal is to remove the water without heating it up so fast that the wood cracks or warps under the intense stress, which can be an extremely delicate balance.

We separate each layer of wood with stickers to allow the heated air to flow over all sides. The better the airflow, the better the final results. As the moisture and relative humidity drops, we can raise the temp until we have achieved our target moisture level of 6-8 percent. While this may seem like a hands-off process, it actually takes daily monitoring and evaluation to get the lumber to dry just right.

If you’re interested in our kiln drying process and would like to get more information, please contact us today!

2017-12-05T15:37:43+00:00

One Comment

  1. Moira Blythe March 16, 2018 at 10:01 am - Reply

    My husband loves working with wood, but he’s never learned much about it. I appreciate your help in understanding that reclaimed wood can be finished kiln drying after 6 days, but new lumber may need a few weeks. This is great information, and I’ll pass it on to my husband!

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