Can Burning Rotten Wood Make You Sick?


After years of being left out in the elements you’re firewood piles seen better days. Rain, snow and who knows what else has gotten into your wood pile and slowly rotted it away. Is it time to throw out the pile, or is it safe to burn? Can burning rotten wood make you sick?

Burning rotten firewood shouldn’t make you sick. Rotten wood isn’t ideal, but it’s perfectly safe to toss in the fireplace or campfire. It will be hard to, might put off some smoke and will burn fast, but it’s not dangerous. I like to start off my fires with properly seasoned firewood that’s easy to light and burn the wet rotten wood after the fires been going for a while.

I wouldn’t go out of my way to burn rotten firewood, but it’s usually better than nothing. Notice that I said “Usually”! Continue reading to find out when you need to throw out decomposing wood and find out ways to prevent your firewood from rotting in the first place.

Will Burning Rotten Firewood Make Me Sick?

Burning rotten wood isn’t that big of a deal. Rot and decay is part of the natural decomposition process. It doesn’t matter how well you take care of your firewood. You can temporarily delay the decomposition, but the wood will eventually rot. You can let mother nature run its course or you can burn the rotten wood.

So why do people avoid burning rotten wood? Does burning rotten firewood make you sick? No burning rotten wood should not make you sick. Just watch out for mold and fungal growth, which can cause breathing problems in people with asthma and severe allergies. Even in those extreme cases people are usually safe as long as you burn the wood outside.

The Problem With Burning Rotten Wood

There are a few small problems when dealing with rotten wood. Rot and decay is accelerated by moisture so the wood will probably be wet. You can test the wood using a cheap/fancy moisture meter (like this one) or you can just assume that the wood is wet and therefore not properly seasoned.

You can burn wet firewood but it will be much harder to light, put off a lot of smoke, and smolder at a low temperature. None of that is great when you’re trying to build a fire. I stopped screwing around with kindling and picked up a propane torch a few years ago.

I picked up a cheap $30 harbor freight torch, but I’ve been eyeing this Flame King Torch that comes with an ignitor(don’t need a lighter). It doesn’t matter how wet your wood is a propane torch will be able to light it in a minute or two. Plus it’s basically a mini flamethrower so it’s really fun to use.

There’s another major issue you’ll run into with rotten decayed wood. A large chunk of the woods stored energy was already used in the decay process. So it will burn fast and not put off as much heat. That’s not that big of a deal when mixing it in with regular wood, but worth mentioning.

What Causes Rotten Wood?

Rot is part of a trees natural decay cycle, but there are ways to slow it down. Keep your wood dry and it will take a very long time to rot away. Think about some of the old barns scattered throughout the country. Some of those barns are well over 100 years old and they’re still standing strong. They wouldn’t be standing anymore if water had gotten into them.

Wood never gets too old to burn, but it will slowly start to dry out and rot over the course of 100s of years. Old wood burns fast and goes up like a match since it’s almost completely dry. So how do you keep your wood dry to prevent rot.

Seasoning and Preventing Rotten Wood

Keeping your wood dry is the most important step to preventing wood rot. Make sure your wood is properly seasoned to prevent rot. The seasoning process is used to dry out firewood and improve its burn quality. Dry wood will light easier, burn consistently, and won’t put off much smoke.

All it takes is time and proper storage to season your firewood. After 6-12 months of storage your wood should be ready to burn. How do you season firewood?

  • Get It Off The Ground: Getting your wood up off the ground is the most important step in the seasoning process. The bottom 2-3 rows of wood will almost always rot away when firewood is stacked on the ground. You can stack wood on pallets or pressure treated lumber, but I recommend building or purchasing a commercial firewood rack. You can use a cheap tarp as long as the sides are exposed to promote airflow. Metal firewood rack brackets (my favorite) that you use with 2x4s are by far the best option when it comes to commercial racks.
  • Cover Up The Top: At the very least you’ll want to cover up your wood with a tarp. You can build a small wood shed like the one pictured above but that will cost $200-300. Buy a cheap cover off Amazon (my favorite) that works with any commercial firewood rack. They’re really not that expensive and make your wood look and burn so much better.
  • Allow Airflow: Do not cover up both sides of your firewood. Allowing adequate airflow will significantly speed up the seasoning process. The slight amount of rain that blows on the sides of your wood will dry in 2-3 days when the sun comes out.
  • Increase Sunlight: Setup your wood pile in a nice sunny spot to maximize sunlight. Sometimes your options are limited by your yard setup so this isn’t the most important step.

Sometimes It’s Best to Throw Out Rotten Wood

When it comes to firewood, I live by a simple rule. It goes in the fire as long as I can pick up the wood without it falling apart. If your wood is so rotten that it’s falling apart in your hands, it’s time to get rid of it. Here’s another post describing what you should do with a rotten wood pile, but I’ll give you a brief rundown.

You can take toss the wood back into the forest to let it decompose on its own, burn the wood, find a drop-off location, hire a yard waste disposal service, or find other uses around the yard(mulch, garden edging, etc.). It really doesn’t matter how you dispose of the wood. You won’t get much out of burning it once it’s that far gone.

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