7 Great Lumber Drying Kiln Options to Inspire You

Kiln drying lumber is a popular way to prepare wood for sawmilling and here are some amazing kiln projects to get you started

Whether you’re a woodworker preparing for your next project or a sawyer making slabs or boards with their portable sawmill, a lumber drying kiln is a great tool.

Without humidity controls drying can stress lumber and air drying often offers unreliable results. A wood drying kiln lets you control the drying process and gives you the ability to use fans, heaters and various ventilation methods to get your lumber ready for milling faster. 

Kiln drying reduces the moisture content of wood, which is essential for proper machining, gluing, finishing, and further manufacturing. Properly dried lumber has increased strength properties and more resistance to biological deterioration due to fungi and insects.

There are plenty of different examples of kilns out there, so we assembled some great ones from the community of sawyers in the Woodland Mills Product Owners and Community Facebook Group to share what they’ve been working on.

Here are the results:

Examples of Quality Lumber Kilns for Drying Wood

When preparing lumber for drying, it is important to stack boards in uniform layers and piles, maintaining consistent thickness and dimensions to prevent warping and defects. Monitoring the efficiency of your kiln and understanding its load capacity will help ensure optimal drying results. Additionally, regularly checking the moisture content during the drying process is crucial to avoid drying too rapidly and to know when the load has reached the desired moisture content.

These wood kilns use a number of different techniques to get boards and slabs dry, and all are great to use for inspiration for your own kiln builds.

Dehumidification Kiln

Courtesy William J. from the Woodland Mills Product Owners and Community Facebook Group.

Many sawyers use solar power to generate heat for their kilns, but William's kiln demonstrates how to control humidity to have total control over the drying process.

Utilizing a dehumidifier, heaters, fans and an enclosed space, William is able to circulate hot air throughout his stacks of wood to consistently draw moisture content out of the closed environment.

Doing this means he'll have dozens of board feet of dry wood in no time, and he doesn't need to rely on sunny weather to do it.

Massive Board-and-Batten Kiln

Courtesy Roger P. from the Woodland Mills Product Owners and Community Facebook Group.

You might think the outbuilding on Roger's property is a garage or guest house, but in reality this beautiful building is his wood drying shed.

This massive structure, build over multiple phases, features amazing board and battened siding. The size allows Roger to store all of his lumber easily while the windowed sloped roof allows light and heat to get in.

This big kiln means Roger will have lots of lumber for his portable sawmill come spring.

Metal Wood Kiln

Courtesy John P. from the Woodland Mills Product Owners and Community Facebook Group.

Metal is a wonderfully conductive material, able to absorb and retain heat very easily.

So John's idea to build a solar kiln out of sheet metal makes a lot of sense. He says he's using fans to move air around and putting ventilation holes to allow air evaporated moisture to escape. It's a great way to do wood drying, especially if you happen to have sheet metal on hand.

Wooden Solar Kiln

Courtesy Garry F. from the Woodland Mills Product Owners and Community Facebook Group.

Using the power of the sun, Garry's kiln build uses heated air filtered through glass windows.

The large barn doors on the other side make it easy to bring in or pull out lumber. With proper air circulation and good weather Garry's kiln will ensure his green lumber dries and is project ready within the year.

Black Slab Kiln

Courtesy Dave B. from the Woodland Mills Product Owners and Community Facebook Group.

This kiln build, made by Dave so he can reliably dry his slabs, makes good use of black paint.

Black absorbs heat better than other colors. It's why wearing black on a cold day is better than wearing white: black sucks up heat while white reflects it.

By painting the interior and exterior of his wood kiln red, it means heat will be captured and retained more easily. High humidity can be mitigated by venting it out, and Dave has much better able to control the drying process and minimize drying defects.

House Addition Kiln

Courtesy Chris P. from the Woodland Mills Product Owners and Community Facebook Group.

Want a kiln that blends in seamlessly as an accessory to your home?

Chris' kiln has a number of great innovations: he's placed a black tarp over his wood stacks to retain heat and he uses fiberglass insulation to further capture it.

But one of the great takeaways from Chris' kiln is that it takes advantage of the errant heat generated by his home. Homeowners naturally keep their houses comfortably warm, and by cozying his kiln up to his home, he ensures the lost heat is instead fed into his kiln.

Crate Kiln

Courtesy Chris P. from the Woodland Mills Product Owners and Community Facebook Group.

What if you want a small kiln with a tiny footprint for drying a small amount of wood?

Chris' crate-based kiln is creative, and takes up a small amount of space. Because it doesn't require as much air flow, you can use a smaller fan and less energy to create and circulate heat. It's a novel concept that may be useful for landowners who only want to kiln dry a small amount of wood, or have limited space to do it.

Advice for building your own lumber kiln

The above kiln samples demonstrate how you can use size, shape, color, various technologies and knowledge of wood science to control humidity.

Proper drying is crucial: Always compare your drying rate with the safe drying rate for each species to prevent defects. Maintaining uniform thickness and dimensions in your boards is important for consistency and to avoid warping and other drying defects.

Kiln drying also increases resistance to insects and fungi, improving the durability of your wood. This step is a vital part of the manufacturing process for high-quality forest products.

Other techniques you can practice as well that will help your wood dry:

• • End coating with a latex paint or a similar product can reduce checking

  • Measure the relative humidity (the moisture content in the air) of your kiln to ensure you’re space is dry enough

  • Having multiple kilns, or space for multiple batches of wood, is great because you can rotate your piles and always have fresh, dry wood to work while your other piles are drying

  • If you’re on a budget look for equipment you can get second hand, like space heaters and box fans, that can easily create and circulate heat

  • Ensure you’re following best practices for stacking wood, such as stickering it to allow air to go between the boards, so you have quality lumber at the end

  • Have a thermometer to check the temperature and a moisture meter to routinely verify the moisture content of your wood

  • Species like pine vs red oak will dry differently, so have separate piles for different species

  • Why not take advantage of the space inside your kiln? If you have firewood that needs drying, toss it in there too