Why Is There A Big Difference Between Kiln Dried And Air Dried Lumber? A blog about the differences between certe and air dried lumber.

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Kiln drying is a process that ensures that your lumber has a consistent moisture content and will not warp, twist, crack or shrink. Kiln drying forces the moisture out of lumber, instead of allowing it to dry over time in the air.

Why Is There A Big Difference Between Kiln Dried And Air Dried Lumber?

The biggest difference between kiln dried and air dried lumber is the consistency of moisture content. When you purchase kiln dried lumber from any reputable dealer, you are guaranteed that the moisture content will be no higher than 19%. The reason for this is that if you have a piece of kiln dried lumber with a higher than 19% moisture content, there is a chance that it can warp and twist.

Air dried lumber varies greatly in its moisture content. Depending on where you live (in terms of humidity) and how long your wood has been stored in the open air, you could have anything from 5% moisture content to 15% or even more. This means that there is no guarantee as to how much your wood will move once you start using it. If you use air dried lumber at 12%, which is slightly damp, there is a very high likelihood that it will warp and twist once it dries out.


Air-dried lumber, on the other hand, is when the moisture content is allowed to decrease due to the lumber being stored in a shed or warehouse, or another type of air drying facility.

The rate at which air-dried lumber dries varies greatly depending on a number of factors, such as:

The thickness of the wood

The density of the wood

The shape of the wood

The amount of air circulation present in the storage area

The temperature and humidity levels in the storage area

Seasonal variations in climate factors, such as higher humidity levels during spring months and lower humidity levels during fall months.

What Is The Difference Between Air Dried And Kiln Dried Lumber?

The difference between kiln-dried lumber and air-dried lumber is the speed at which the moisture is removed from the wood. Kiln-drying uses an artificial application of heat to dry the wood, while air drying allows the wood to dry naturally.

The key to understanding why there is a difference lies in the speed at which a material dries. The faster it dries, the more shrinkage you will have. The slower it dries, the less shrinkage you will have.

It’s not that air-dried lumber has zero shrinkage–it doesn’t. However, because a piece of air dried lumber slowly releases moisture over time, the moisture evaporates at a much slower pace, minimizing shrinkage and mitigating other issues such as cupping and warping.

Kiln-dried lumber goes through an artificial drying process in a chamber under carefully controlled conditions. This process can take anywhere from several days to several weeks depending on what type of wood is being dried, how thick or dense it is, and what environmental conditions are outside of the kiln itself.

Because kiln-dried lumber dries quickly (in comparison to air drying), it shrinks rapidly as moisture is released from its cells and fibers.

One of the most common questions that homeowners ask us is what is the difference between kiln dried and air dried lumber. The short answer is that kiln dried lumber has been dried in a kiln machine while air dried lumber has been exposed to the outside elements.

Kiln dried lumber has a moisture content of 19% or less. It is the best type of wood for indoor use since it has a lower moisture content than air dried wood. Woodworkers who are looking for good quality wood for their projects usually prefer kiln dried lumber over air dried lumber.

Kiln dried lumber is best for painting or staining since it does not warp and crack easily compared to air dried lumber. It can also be used for furniture building, framing, and other indoor projects where you want your wood to stay in its natural state without warping, twisting, or cracking.

Kiln Dried Lumber vs Air Dried Lumber

You have a number of options when selecting your material for your deck, roof or patio. One of these options is the type of timber you will be using. You can use air dried lumber, or kiln dried lumber. Both types have their advantages and disadvantages, and it is essential to know exactly what these are to ensure that you make the right choice for your project.

Kiln Dried Lumber

Kiln dried lumber is timber that has been placed in a large drying chamber, known as a kiln. These machines use intense heat to dry out the wood, which removes sap and moisture from the timber. The major advantage of using this type of lumber is that it has a very low moisture content, which means that it will not shrink or warp when you are using it. It also has no sap residue in the wood, which means that you do not need to treat it to protect it from pests and insects.

The main disadvantage with kiln dried lumber is that it is more expensive than air dried lumber. In addition, some people believe that the heat used in drying the wood can distort the grain slightly and reduce its strength.

Kiln dried lumber is lumber that has been dried in a dry kiln. The moisture content in the lumber is reduced to a level that is suitable for interior use. The ideal target moisture content of kiln dried lumber ranges from 6% to 8% depending on the end use of the wood product.

Air dried lumber is lumber that has been stacked and stickered in a well ventilated area and allowed to dry naturally over time. Air drying will typically reduce the moisture content of the wood down to 19% or more depending on the species and thickness of the wood.

The benefits of kiln dried lumber are numerous. A primary benefit is that it will not shrink or warp as much as air dried lumber when it comes in contact with low humidity environments such as an air conditioned home or office building. This makes kiln dried lumber more dimensionally stable than air dried lumber, which makes it easier to work with, especially for installation of hardwood flooring or furniture making. Kiln dried lumber can be purchased at low moisture contents, which reduces its tendency to warp, twist or cup when going from a high humidity environment to a low humidity environment. Kiln drying also improves the strength properties of wood by reducing its moisture content which makes it less prone to splits

The most common types of kiln dried lumber are KD HT and KD S-GRN. Both of these products are exposed to high heat temperatures, but the difference is in how long the lumber is exposed to the heat.

KD HT (kiln dried hardwood temperate) is heated to approximately 190 degrees F over a time period that can last up to 5 days.

KD S-GRN (kiln dried special green) is heated to approximately 120 degrees F over a time period that can last up to 14 days.

Both of these types of kiln dried lumber have an average moisture content lower than 19%.

Air Dried Lumber

Air Dried Lumber refers to lumber that has been stacked and placed in an open air environment for a period of time. The amount of time the lumber will spend drying depends on the type of wood, thickness, and how it was stacked. Environment conditions such as humidity, wind and rain can also slow down or speed up the drying process. The average moisture content for air dried lumber is between 15%-19%

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