Whether you’re a woodworker or you have some wet firewood, you might be wondering how long it will take to dry before you can use it.
In this post, I’ll answer the question “how long does it take wood to dry?” and include a few tips to help you speed up the drying times. Let’s get started!
How Long Does it Take Wood to Dry?
Traditional, air-cured firewood can take anywhere from six to eighteen months to fully dry. However, you can get much faster results with kiln-drying.
That said, there are many variables involved.
For example, different types of wood will take longer or shorter to cure. Here’s a quick overview of air-drying, kiln-drying, and how both methods work.
Air-drying is the most popular method for curing firewood and other types of wood, and it’s the only way to cure your own without any special tools and equipment.
Air-dried firewood can have as little as 20% moisture, depending on how long you leave it to season.
Bear in mind that you probably won’t get wood this dry from a vendor. Vendors need to maximize their profits, so you can expect 30% or even 40% moisture. For this reason, it makes sense to order your firewood about six months in advance. This way, you’ll be able to guarantee that your wood has completely cured by the time you need it.
Several factors can affect your curing rate which include:
- The density of the wood – Denser woods are less porous, and also contain more moisture, to begin with so they’ll take longer to cure.
- The species of wood – Some woods, like pine, contain large quantities of sap and resin. I wouldn’t recommend burning them to begin with but if you do, they’ll need to cure for longer.
- The relative humidity – Humid conditions make wood take much longer to dry. Along the same lines, you’ll usually see faster curing during the summer.
Pros of air-dried firewood:
- You can cure the wood yourself.
- It’s inexpensive.
- You don’t waste extra energy powering a kiln.
Cons of air-dried firewood:
- It doesn’t get as dry as kiln-dried firewood.
- It can develop mold, fungus, and moss as it’s curing.
- You have less control over your results.
If you’re looking for a quicker way to reduce the moisture content of your wood, the kiln drying method is your best option.
Kiln-dried wood has been around for a long time and it’s the exact process lumber manufacturers use to create consistent dimensional lumber.
Because the wood is in a controlled environment, you don’t have to worry as much about variables like humidity.
In kiln-drying, a manufacturer places the wood inside a negatively-pressured chamber. Because the chamber is under negative pressure, air from the outside naturally flows in. As the air flows in, heating elements raise its temperature to at least 160 degrees.
The high temperatures cause moisture to evaporate from the wood faster than it otherwise would. Kiln-dried wood can contain as little as 5% moisture.
If you choose to buy kiln-dried firewood, try to find information on the manufacturer’s curing method. There’s a big difference between high-quality kiln-dried firewood and premium wood.
USDA regulations require manufacturers to dry wood at a minimum of 160 degrees for at least 75 minutes. That’s enough to kill any bugs and reduce the moisture level to around 25%. To get the driest wood possible, you need a hotter kiln and longer times. 250 degrees for 48 hours is the gold standard and will dry most woods to 5% moisture.
Pros of kiln-dried firewood:
- It’s drier than air-dried firewood.
- You don’t have to worry about bugs or mold.
- It drys wood faster
Cons of kiln-dried firewood:
- It costs more.
- You can’t do it yourself.
- Some vendors only dry their wood to the bare minimum.
How Long Does it Take Pressure Treated Wood to Dry?
If you’ve just picked up some pressure treated lumber from your local hardware store, it might still be slightly wet or damp.
Pressure treated wood takes anywhere from a few weeks to a few months to fully dry.
How Long Does it Take Wood to Dry Before Painting?
If you’re looking to give your surface a new appearance with a fresh coat of paint, you need to make sure it is dry to avoid a poor paint job.
Depending on the type of wood and the amount of moisture content applied to it, it usually takes around a few days to dry before painting assuming a light amount of water has coated the surface.
How Long Does it Take Wood to Dry After Pressure Washing?
How to Cure Your Firewood Quickly
Want to speed up the curing time of your firewood? Give these tips a try to have your wood dry faster!
Chop Your Wood
Depending on your fireplace, it may be able to accommodate very large logs. But the larger the piece of wood, the lower the ratio of surface area to volume. The lower the ratio, the longer your wood will take to cure.
So regardless of the size of your fireplace, cut your logs into small, easy-to-manage chunks. This will maximize the surface area-to-volume ratio and speed up the curing process.
Place Your Logs Strategically
When you stack your logs, don’t stack them directly on the ground.
The bottom logs will get soggy and decay, and insects can infest the entire stack.
Instead, you need to raise your firewood a few inches off the ground. You can buy a firewood rack from many home improvement stores, or save money by using some old pallets or cinder blocks.
When you elevate your wood off the ground, you provide space for air to flow underneath, kicking your drying process into overdrive.
Stack Your Logs Correctly
When you picture a stack of firewood, the logs are probably all pointing in the same direction. This is the most efficient method for storage and transport. Unfortunately, it’s terrible for curing.
Instead, use alternate layers of logs, which each layer stacked at a right angle to the one beneath it. This ensures consistent spacing, as well as improves airflow through the middle of the stack.
Keep Your Firewood Under Cover
Nothing is worse for drying firewood than rain.
It’s important to keep your wood covered, but it’s just as important to use the right kind of cover.
A dark cover like a tarp will keep light from hitting the wood. This is worse than no cover at all. You can store cured firewood under a solid tarp. But while the wood is drying, the cover should be transparent.
Your wood should also get plenty of airflow. In other words, you don’t want to enclose the wood without proper ventilation.
The most efficient method is to build a backyard curing shed with a transparent acrylic roof. Cut a vent into one side of the shed and build a small fan into the other side. Air and sunlight will get in, and rain will stay out!
If you want more help, check out the video below!
How do I Know When my Wood is Dry?
If you want to scientifically measure your wood’s moisture content, you can order a moisture meter.
A moisture meter is a handheld device with a pair of fine metal pins at the end. You stick the pins into a log, and the device tells you the moisture percentage.
But for most people, a moisture meter will be overkill.
Here are some signs that your wood is dry enough to burn:
- There are cracks in the grain at the ends of the logs.
- The wood feels dry to the touch.
- The wood is darker or has undergone greying.
- The logs feel lighter.
There are two other tests you can perform.
First, knock two logs together. If the wood is dry, the sound should be sharp. It should sound like two wood baseball bats clacking against each other. If the logs are wet, they’ll make a dull thud.
Second, throw one of the logs in your fire. If it hisses, it’s still wet. If it doesn’t, the pile is ready to burn.
What if my Firewood Got Rained on?
There’s no need to panic if you accidentally left your cured firewood in the rain. It will absorb a little moisture but should normally dry out within a week. That said, there are some variables involved:
- The local weather – If you live in a dry area and the weather is windy, your wood will dry more quickly. Under the right conditions, it can shrug off the effects of rain in as little as two days. Then again, your area might receive a lot of rain. Under those conditions, the wood could remain wet for as long as three weeks.
- The type of wood – While hardwood takes longer to cure, it doesn’t suffer as much from rain. In this case, its less porous nature works to its advantage. More of the rain simply rolls off the surface. Softer woods will absorb more water and take longer to dry out.
- The humidity and size of the wood – High humidity will make it take longer for your logs to dry. And as with initial curing, smaller logs will dry out faster.
Wood Moisture Content – Understanding the Basics
So, what is a “good” moisture level? And how much moisture does wood have to begin with?
Let’s start with the basics. Trees are plants, and like most plants, they produce energy via photosynthesis. Oxygen from the air reacts with water from the ground to produce energy for the tree.
The tree’s trunks and branches act as conduits. They bring water from the roots to the top, and nutrients from the leaves to the bottom. When a tree falls – naturally or otherwise – the green wood contains an average of 50% water by weight.
Some low-quality firewood contains as much as 40% moisture. While this wood will burn, it’s far from ideal. Good quality firewood will contain 20% moisture or less.
In most parts of the country, this is achievable.
Wood will dry to as little as 14% at 75% relative humidity. But at 99% humidity, wood will only dry to around 23%.
Let’s say you live in a humid area and you order some high-quality kiln-dried firewood with a 5% moisture level. Leave that wood outside for a year, and it might have 23% moisture.
That said, changes in humidity can be a concern for carpenters or woodworkers. Wood will naturally swell and shrink as the humidity changes, as well as with temperature changes.
Why is it Important to Burn Dry Firewood?
The main reason to burn dry firewood is that wet wood simply won’t burn. But why is drier wood better than wood that’s dry enough? Here are several reasons you should use the driest firewood possible:
- Dry wood produces less smoke – Have you ever gone to a bonfire and spent the entire time with smoke blowing in your face? Dry wood might not stop the wind from blowing in your direction, but at least it’s less smoky.
- Dry wood is better for your chimney – When your wood burns, the water evaporates as steam. Most of it passes harmlessly through the top of your chimney. Unfortunately, some of it will cling to the sides and combine with soot to form creosote. Creosote is flammable, so this buildup creates a greater risk of chimney fires.
- Dry wood burns hotter – When you put a wet log on the fire, it wastes energy. Yes, the wood will burn and produce heat. But all the water in the wood absorbs heat until it evaporates. It’s like turning up your thermostat and putting a bucket of ice in front of the heating vent.
- Dry wood is easier to light – Once you’ve built up a good coal bed, pretty much any log will burn. But when you’re getting started, you need dry wood.
- Dry wood smells better – Dry wood produces a crisp, clean aroma. Wet wood, on the other hand, tends to burn with an unpleasant, musty odor. When you use it as bonfire fuel, the smell lingers. Remember how wet wood produces steam? The steam carries the odor through the air and sticks to your clothes.
- Dry wood is better for cooking – When you’re cooking, you need consistent, reliable heat. It’s tough enough to get a steady heat when you’re cooking over wood, but it’s even tougher with wet wood. Wet wood causes the temperature to drop when you add it and spike later on.
Why is it Important to Use Dry Wood for Carpentry?
If you’re using wood for a carpentry project, the moisture content of the wood will matter more. In that case, your wood needs to be very dry – 10% or less. Here are three reasons to always use dry wood in your carpentry:
- Wet wood is susceptible to rot – Moisture in your wood provides fuel for mold and fungus. In the short term, this might not be obvious. If you build a chest out of wet wood, it won’t immediately start sprouting mold. But if you want your carpentry project to last for years, you should start with dry wood.
- Wet wood is harder to work – Sawing or sanding wet wood is challenging, and it’s easy for your blade to bind up. Sanding is harder because the material doesn’t want to turn into dust. And tools like a Dremel or a router will have a tougher time cutting a clean shape.
- Wet wood is weak – Trees have evolved to bend in the wind, so they need to be flexible. But when you build a structure, you want it to be rigid. Gaps between the fibers in the wood weaken its overall integrity and make it less reliable. Dry wood will hold its shape more reliably, and won’t sag or warp as easily over time.
Final Thoughts on How Long Does it Take Wood to Dry
Firewood can take anywhere from a few weeks to over a year to completely dry depending on its current moisture content, and other conditions such as the relative humidity, whether or not it gets direct sunlight, and more.
Air drying wood for carpentry or woodworking can usually take a few weeks depending on its moisture content.