Can You Store Kiln Dried Lumber Outside?

When it comes to storing lumber, one of the most common questions is: can you store kiln dried lumber outside? The answer isn't as straightforward as a simple yes or no. It depends on several factors, including the specific type of lumber, the climate you live in, and how long you plan to store it. Let's delve into the intricacies of storing kiln dried lumber outside to help you make an informed decision.

Kiln dried lumber is wood that has been dried in a kiln to a specific moisture content, typically around 12-15%. This process makes the wood more dimensionally stable and reduces the risk of movement and warping once it's installed. However, it doesn't make the wood completely immune to the effects of outdoor storage.

Understanding the Impact of Outdoor Storage

The moisture content in kiln dried lumber may be lower than that of green lumber, but it's not at its equilibrium moisture content (EMC) yet. EMC is the moisture content wood reaches when it's in balance with its surrounding environment. When stored outside, kiln dried lumber will continue to exchange moisture with the air until it reaches its EMC, which can take anywhere from a few days to several months.

If the EMC of the wood is below 20%, it's generally considered safe to store outside. However, if the EMC is significantly higher, the wood may be more susceptible to issues like cracking, warping, and checking (small cracks that develop on the surface of the wood). These problems can occur when the wood expands and contracts as it absorbs and releases moisture.

Factors Affecting Outdoor Storage

One of the primary factors affecting the storage of kiln dried lumber outdoors is climate. In humid regions, the EMC of wood can be as high as 20-25%. In drier climates, it can be around 10-15%. If you live in a humid area and plan to store your kiln dried lumber outside, you may need to take additional precautions to protect it.

Another factor to consider is the duration of outdoor storage. The longer you store your lumber outside, the more time it has to absorb moisture from the air and potentially experience warping or checking. If you only need to store your lumber for a short period, the risks are generally lower.

Protective Measures for Outdoor Storage

If you decide to store your kiln dried lumber outside, there are several protective measures you can take to minimize the risks. One option is to use a tarpaulin or other waterproof cover to protect the lumber from rain and snow. However, it's important to ensure that the cover doesn't trap moisture, as this can lead to mold and rot. You may also want to elevate the lumber off the ground and provide adequate ventilation to prevent moisture from building up.

Another option is to use a storage shed or other enclosed structure to protect your lumber from the elements. This can help maintain the moisture content of the wood and reduce the risk of warping and checking. However, it's important to ensure that the storage shed is well-ventilated to prevent moisture from building up inside.

Alternatives to Outdoor Storage

If you're concerned about the risks of storing your kiln dried lumber outside, there are several alternatives you can consider. One option is to store your lumber indoors, in a cool, dry place with plenty of ventilation. This can help maintain the moisture content of the wood and reduce the risk of warping and checking.

Another option is to re-kiln the lumber before use, which can help bring the moisture content back down to the desired level. However, this can be a time-consuming and costly process, so it's best to avoid it if possible.

Storing Lumber for Outdoor Projects

If you're storing lumber for an outdoor project, it's generally recommended to use lumber that's specifically designed for outdoor use. This lumber is typically treated with preservatives to protect it from rot, decay, and insect damage. It's also usually stored and dried in a way that makes it more resistant to the effects of outdoor storage.

Of course, even outdoor-rated lumber can be affected by extreme temperatures and high moisture levels. If you're storing outdoor-rated lumber for a prolonged period, it's still a good idea to protect it from the elements and monitor its moisture content.

Storing Lumber for Indoor Projects

If you're storing lumber for an indoor project, it's generally less critical to protect it from the elements, as the indoor environment is typically more stable. However, it's still important to provide adequate ventilation to prevent moisture from building up and causing mold or rot.

Another consideration is the aesthetic of the wood. If the appearance of the wood is important to your project, you may want to store it in a place where it won't be exposed to direct sunlight, which can cause the wood to fade or change color.

In the world of woodworking, there's no one-size-fits-all answer to the question: can you store kiln dried lumber outside? The key is to understand the factors at play and take appropriate steps to protect your lumber, whether that's through outdoor storage with protective measures, indoor storage, or using outdoor-rated lumber. By doing so, you can help ensure that your lumber is MOSFETure; safe and stable when you're ready to use it.