Will Polyurethane Be Enough To Kill Off Bugs In Wood Furniture?

Polyurethane can do a lot of things.

It can protect wood from scratches and scrapes. And it can make the surface of wood water-resistant, and better able to shrug off water-damage.

Plus, certain specialty polyurethane finishes, can weatherproof wood against the great outdoors.

So, if it can do all that, what can polyurethane do about wood bugs?

Well, in this post you’ll learn how polyurethane can inadvertently combat wood bugs — and why it’s still isn’t very good at it. You’ll also find out why pH levels matter when it comes to getting rid of bugs.

And keep reading to discover how the best way to get rid of little critters is to turn up the heat…

will polyurethane kill bugs in wood

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Will Polyurethane Get Rid Of Any Bugs Inside Air Dried Wood?

On it’s own? No, it won’t.

Unless polyurethane comes with added insecticide, there’s nothing inside this wood sealer that will get rid of bugs.

At best, polyurethane will trap bugs — sealing them in with no escape.

But, you’d have to seal every side of that wooden furniture to be sure. And, this is easier said than done.

Related Post: Will A Polyurethane Coat Ever Dry In Cold Weather? [What You Need To Know]

So What Can You Put On Wood (Without Damaging It) To Get Rid Of Bugs?

To get rid of wood bugs (even bacteria), you need to saturate wood with an alkaline solution.

Why? Well, because bugs pretty much hate it.

Bugs like pH neutral environments (and can sometimes survive slightly acidic ones). However, alkaline solutions, (i.e. anything above pH level 7), is pretty much bug-Kryptonite.

Related Post: What To Do About White Mould Under Your Hardwood Floorboards

And Which Alkaline Solution Do You Recommend?

One of the best solutions you can use on wood (without harming timber) is Borax.

Borax (sodium tetraborate) is a type of salt that looks a lot like Baking Soda (sodium bicarbonate). Except Borax is a touch more alkaline.

Borax has a pH level of 9.5, which is higher than Baking Soda’s pH 8 level.

This is why Borax is so much better at getting rid of wood bugs — and mold bacteria too.

And How Do You Use Borax To Treat Bugs Inside Wood?

All you need to do is mix 1/4 cup (35 grams) of Borax in 18 fluid ounces (1/4 liter) of water.

Pour that watered-down Borax solution into a spray bottle. And then you can topically treat the bug-nested section of wood.

Now, while Borax will work, the last thing you want is to wholly saturate wood with a water-soluble solution.

That’s because that water will become quickly absorbed by wood. And this, in turn, could lead to wood cracking and splitting later on.

So, if a topically applied borax-treatment isn’t working, then a heat-treatment is your next best option.

Can You Really Get Rid Of Wood Bugs Naturally Using Heat?

You certainly can. In fact, this type of treatment is called Kiln Drying. And it involves baking wood in a kiln oven for up to 36 hours.

Now, Kiln Drying is mainly used as a way to quickly season newly cut lumber. Regular Air Drying can take up to 6-12 months before wood is dry enough to work with.

However, with kiln dried wood, that time is reduced to as little as 3 days.

On top of that, this particular method of wood seasoning will also completely get rid of those critters.

Related Post: Kiln Dried Vs Air Dried Wood: Which Type Of Seasoned Lumber Is Right For Your Furniture?

Nonetheless, Kiln Drying does have its disadvantages; namely time and expense.

Buying a kiln oven is expensive. And, once setup, you will have to constantly monitor things inside the oven for days.

I Don’t Mind All That. How Do I Kiln Dry Wood?

Well, you could buy one, but they are often over priced. So, you’re better off simply building one yourself.

And one of the single best wood kiln building tutorials out there can be found on Farm-Craft101’s channel. In the video below, you will learn how to make a wood kiln using items you can purchase from most hardware stores.

You can get started on your DIY wood kiln by watching the video below:

But How Do You Keep Bugs From Eating Wood In The First Place?

You need to make lumber difficult for bugs to eat.

There is a good reason why bugs like rotting wood. Rotten wood is soft enough for them to chew.

Related Post: Rotting Wood Around Your Sink? 3 Ways To Protect That Wooden Worktop

So, the best way to stop wood-munching critters, is to seal wood with a water-resistant finish.

A wood sealant such as polyurethane, spar urethane or epoxy, are very water-resistant. Much more so than penetrating oil finishes, such as Tung oil or Boiled Linseed oil.

To Wrap Up, Here Are The 3 Key Takeaways From This Post…

  • 1). To get rid of wood bugs, you can topically treat bug-infested sections with a water-soluble Borax spray solution.
  • 2). Borax is an alkaline substance, more so than Baking Soda. It can be used to get rid of wood bugs, and even wood rot.
  • 3). Alternatively, you can naturally get rid of wood bugs using a heat-treatment called ‘Kiln-Drying’. This treatment involves baking wood inside a Kiln oven.


Bandelin, F. J. “The effect of pH on the efficiency of various mold inhibiting compounds.” Journal of the American Pharmaceutical Association 47.10 (1958): 691-694.