For you to enjoy using wood for construction or any kind of woodwork, you must properly dry it to an acceptable moisture level. The most common and the simplest method to dry wood is by air drying, which involves allowing it to sit at a specific humidity level in order to obtain the dryness level that you desire. While air drying is simple, it can also take a lot of your time, ranging from several months to years. Typically, the time involved in drying wood can vary significantly depending on the species of wood you’re working with, the initial moisture level of the greenwood, wood thickness, weather conditions, density, and the drying method used.
How long does it take to dry wood?
How long it takes to dry wood depends on the way you dry the wood, the thickness , and the moisture level you want to end at. If you air dry wood you can expect one year per inch of thickness to dry out, depending on the humidity level you can reach a moisture level of around 14%. Kiln drying is a more complex and much faster method. Modern system can dry a 1 inch thick piece of green lumber in less than 12 hours to an 18% moistere level. But a 1 inch thick piece of red oak can take up to 30 days to reach a moisture level of 8%.
The quickest answer is, it can take around a few months to a year for wood to dry completely. Depending on the species of wood you’re using, the weather or climate changes for that particular year, the thickness and length of the log, and the way you dry the log all play an important part in the drying time. There’s a general rule that states that you must allow per inch of wood thickness at least one year of drying time. Hence, this means that if you will be drying a large piece of log, then you should be looking at a very long drying time, especially if you want to use the natural method of seasoning wood. However, if you don’t have that much time to spend, then you can try out some easy and faster methods of drying wood completely. Do you want to know how long it takes to completely dry wood? Then you’ve come to the right place. This article will not only show you how long it takes, but it will also walk you through the various methods in achieving that.
Understanding Moisture Content in Wood
Wood, which is obviously gotten from trees, is considered a hygroscopic material, which means that it is capable of absorbing or releasing moisture depending on the humidity level of the surrounding environment. If air is humid, water vapor in the air will simply seep through the wood’s pores into the wood, causing its moisture content to increase. On the other hand, if the air is dry with low humidity, then moisture is released from the wood’s pores, causing the moisture content to reduce.
The moisture content of dried wood- assuming it’s air-dried- varies depending on the humidity level of the surrounding. Air-dried wood will dry out to a moisture content level of about 14% when exposed to a relative humidity of 75%. However, when exposed to a relative humidity of 99%, wood will only dry out to about 22% to 30% moisture content. This level is typically too low for any woodwork and for firewood to burn efficiently, and it results in excess smoke or ashes as well as low heat.
How Long Does It Take Wood To Dry Completely?
As stated above, there are several factors that can affect the drying time of wood. The main factor is the method you use to dry the wood. The simplest and cheapest way to dry wood is by air-drying, but the fastest and most effective way is to employ a kiln drying process. We will be discussing these two options next.
● Air-Drying Wood: The One-Year Rule
When air-drying wood, there are different steps you must follow. First, to get the wood to season more quickly, it has to be chopped. If the piece is smaller, it will dry out more quickly. In fact, as a general rule, most types of wood will take about one year per inch of thickness to dry out. So if you happen to dry a two-inch log, it simply means that you’ll need to spend two whole years for it to dry completely to be able to burn efficiently.
The other factors that affect the drying rate of wood include the relative humidity. In a humid area, it will take longer for wood to dry than in a place with extremely dry air. The spacing between wood is also important so that air can flow through the cut logs, causing moisture to escape. In addition, some types of wood dry faster than others, so you might want to put that into consideration. If you’ll be drying wood by yourself, then you can easily control some of these elements. However, if you’ll be buying already seasoned firewood, then there is really no way to know if the wood was seasoned properly to your taste. Normally, a well-seasoned wood can lose as much as moisture till it reaches a moisture content of 20%, however, some vendors might deliver wood of 30-40% moisture content to you under the guise of ‘well-seasoned’.
This is why many people who love great fires prefer to dry wood themselves or employ the kiln drying method. Another problem that comes with seasoned firewood is that it starts to decay. The moisture in the wood can attract mold or fungus as well as bugs that break them down. Since seasoned wood takes longer and usually results in a product of lower quality, using kiln-dried wood is highly recommended. Let’s talk about that next.
● Kiln Drying
Kiln drying is a newer, faster, and more advanced method of drying wood completely, and it is used by many lumber and wood producing companies to remove moisture from wood. A kiln is simply used to enhance the drying process and make it faster. There are different types of kilns used for drying out lumber, however, the design is the same for all. There is a large insulated chamber where the temperature, airflow, and relative humidity is significantly controlled to reduce moisture safely and efficiently to dry the wood completely. Kilns are capable of drying wood more evenly, minimizing any moisture gradients between the outer surface and the inner core. With this method, wood dries quickly and drying defects (usually associated with rapid and uneven drying) are avoided.
Here, wood is placed in a vacuum chamber where it is exposed to heated air. The negative pressure of this chamber, as well as the heated air, essentially causes the moisture within the wood to escape quickly to the surface where it is then evaporated, therefore lowering the moisture content of the wood. This method is proven to be more effective than the air-drying method. Where air-dried wood maintain moisture content of 20% to 30%, kiln-dried wood may have a moisture content as low as 5% to 15%. Modern system can dry a 1 inch thick piece of green lumber in less than 12 hours to an 18% moistere level. But a 1 inch thick piece of red oak can take up to 30 days to reach a moisture level of 8%.
Tips for Storing and Drying Wood Faster
Since you already know the ways to dry wood, we’ll be dropping a few tips to achieve this faster. Always remember that anything above a moisture content of 20% moisture isn’t quite ready. There are different factors that affect the drying rate of wood, such as the yearly climate. And the fastest method to dry wood is by using a kiln. Finally, hot and dry weather will dry out a piece of wood faster than the cool and damp climate.
Here are some tips that will help:
● Increase the Air Circulation
One of the best ways to speed up the drying process is by increasing the airflow around each piece of wood. To achieve this, stack the wood on a rack with no contact with the ground. This will allow air to flow underneath. Also, do not stack wood against a wall as air won’t be able to circulate behind the wood.
● Stack the Right Way
Moisture usually escapes wood from the cut ends and not the center. Hence, it is important that both ends of wood are exposed to the wind. This will cause them to dry faster than when the wood is stacked against the side of a barn.
● The size of the Log
Cutting the logs to fit into your fireplace is wise, but this also applies to the drying processes. It is obvious that a smaller log will dry out faster than a larger log. Also, it will save you the stress of having to process your wood again before using it.
● Let the Sun do its Work
Another way to speed up drying time is by spreading your freshly-cut logs out in the sun (could be on your sidewalk, driveway, or drying rack). When you stack them up, the bottom layers won’t dry as fast as the ones on top as they’re not in direct contact with sunlight. Making sure each piece of wood is well exposed to the sun is very helpful. Some people, however, may not have enough room to achieve this; instead, you should monitor the top layer of the wood since they dry faster. Once they become dry, move them to a storage rack, exposing the second layer of wood to the sun.
That being said, you can now determine how long it takes to dry wood completely. It all depends on how you want to use the wood (firewood or woodwork), the preparation method, the method of drying, and how much moisture it contains beforehand. We hope this piece has been helpful. Good luck!