How my log cabin went bug free

How to Go Bug Free: Keeping Insects Out Your Log Cabin

Is it your dream to escape to somewhere more rural?

Do you long to emerge yourself in nature?

Most people’s desire to build a log cabin stems from the urge to be closer to nature, surrounded by an abundance of wildlife, birds, and … bugs?!

Much to our disdain, log cabins provide a perfect place for insects to nest in, due to their proximity to forests, plants, flowers, and the earth; however, there are multitudes of different ways to stop these unwanted invaders and ensure you extend the longevity of your cabin.

Contrary to popular belief, these techniques are not laborious or overly time-consuming.

The amount of work it takes to maintain a log cabin is probably the same if not less time-consuming, than maintaining a regular house – so don’t be put off!

Wood Types

Stacked timber logs

Prior to the First World War, wood was mainly imported from huge natural forests that were hundreds of years old; the beauty of this is that the sapwood growth compared to the heartwood growth was minuscule and thus made for a better, more resistant building material:

Sapwood: the living, softer outer layers between the heartwood and the bark. The sapwood carries water and minerals to the rest of the tree.

Heartwood: as the tree grows in width, the sapwood closest to the middle dies and becomes dense hard heartwood.

Nowadays, log homes are typically made from fast-growing trees such as pine, fir, or spruces which mostly consist of sapwood – this wood can be easily attacked by insects unless protected.

Examples of more insect resistant wood include cedar, cypress and hemlock wood.

Without treatment, these more hardwearing woods can also be subject to infestations.

Keep this in mind when selecting the logs you will use for your home, although there are many ways of treating the logs you choose to ensure they are long lasting and as resistant as possible to bugs.

Preventative Treatment

Preventing timber from decaying

Preventative treatment during the construction stage is much more effective and usually less expensive than treating an infestation.

Make sure you follow this checklist of things to ensure you treat your logs correctly:

Dry thoroughly

Once logs have been cut, it is vital that logs are dried properly to ensure no moisture is trapped inside. It is advisable to ensure the logs you are using have been dried thoroughly.

For advice on drying logs properly read this wiki-how article for firewood – but ignore about cutting to size!

Treat with Borate Treatment

This treatment helps to protect the wood from pests. It is a fairly simple, non-time-consuming process whereby the logs are dipped into borate solution, sometimes also being pressure treated to make sure the deepest parts of the log are protected.

Clean the logs

Logs often collect dirt and mud during the transportation and construction stage, it is, therefore, important to clean them in the correct way. The best way to do this is to let them dry in the sun, and use a brush to wipe away the dirt or use a recommended cleaning solution.

YouTube video

Use a preservative

Applying a preservative to your logs is a great way to protect them from moisture, the preservative acts as a repellent and stops the wood from absorbing water. Depending on the type of preservative you use, you will need to reapply a coat every three to five years.

A good solution to preserve the cabin is Permagard.

You can read more about Permagard on our article about the costs of a log cabin here.

By adding a final coating to your logs you will be giving them extra protection against the sun, water, insects, and general wear and tear.

Use a biocide treatment
This chemical protects against things like insects, mold, and fungi. Although it is harmless to humans and animals, the chemicals kill organisms that feed on wood hence why it is wise to use a biocide treatment.

Ensuring that you care for and treat the logs prior to and during the construction of your cabin will not guarantee that you will have a bug free log home, but, it is a lot less likely that your home will be able to be penetrated by bugs if you prepare it in this manner.

Most insects are in search of moist places so by eliminating moisture, you are lessening the chance of your home being infested.

A good moisture content for your logs is ~20%.

Remedial Log Infestation Treatment For Your Log Cabin

Rotten wood

If you didn’t treat your log cabin properly during the construction stage and are experiencing problems with bugs, there are ways to exterminate infestations and prevent them from building their nests in your home again.


Preventative treatment is typically more expensive than the process of treating wood initially – so if you have the choice treat the timber before use.

A few methods of treating infested wood include:

  • Paste insecticides
  • Spray treatments
  • Injection treatments
  • Fumigation
  • Replace the rotting wood or use residual borate insecticides

Depending on the type of insect there are different ways to treat the issue.

Long Horned Beetles
Long horn beetle

This is one of the most common pests that are found in log homes. The adult beetles derive their name from their long antennae. As larvae, they are legless, white grubs and are sometimes known as round-headed wood borers.

This type of beetle will usually only infest fresh wood, and so it is a matter of how quickly and how well the initial preventative treatment takes place. These beetles will not re-infect the same wood – this certainly is a positive for log cabin owners as it limits the amount of damage a long-horned beetle can do.

Tell-tale signs of long-horned beetles living in your logs are large bore tunnels and circular or slightly oval emergence holes.

Many professionals do not advise treatment; however many homeowners want an immediate control measure. Surface treatments will not reach deep down into the wood and are ineffective; injection treatments may solve small infestations. The other option is fumigation, this provides immediate control, although does not provide residual protection.

Flat-headed Wood Borers
Flat headed wood borers

Otherwise known as metallic wood borers, they are very similar to the above beetles and will not re-infest. They leave flattened oval-shaped emergence holes.

Recommended treatment is the same as long-horned beetles.

Powder Post Beetles
Powder post beetles or Anobiid beetles present more of a problem; they are capable of doing long-term damage because of their tendency to re-infest wood. They like moisture and therefore getting rid of the moisture should be of top priority. They can then be treated with borates.

Old house borers
Old house borers

These are large insects that can have a life cycle of ten years and more. Treatment should be similar to that of the beetles above and can include injection treatments and fumigation.

Carpenter Bees
Carpenter bees

These bees are similar to bumblebees but have a solid black shiny abdomen. The female bees use their teeth to bore into softwood and leave perfectly round holes, about half an inch in diameter, and then tunnels through the wood with the grain.

The best treatment for bees is to inject dust formulated insecticide. The holes should then be sealed with a dowel rod or silicone sealant.

Carpenter Ants
Forest black ant

Carpenter ants like to nest in buried wood or around windows and doors, although they will not cause damage quickly, they can be a nuisance.

Again, as is recommended with all of these infestations, the cause of the moisture should be identified and remediated.


Termites usually start their infestation at the ends of the logs so regular checks would be advisable. The recommended treatment would be to inject with an appropriate pesticide.

In essence, getting rid of the bugs is not solving the root of the issue; The reason the bugs are infesting is that there is moisture in the wood.

Therefore, the most effective way to ensure bug-free log cabin life is to replace the rotting wood where possible, or use residual borate insecticides and to make sure you keep your cabin’s moisture content around ~20%.

Take sensible precautions

Ensure that you check the exterior of your cabin regularly – rotting wood is an all-time favorite for lots of insects to either use as food or to make their nest. It is useful to keep a log or diary and record when you have checked and things you notice.

Crevices and cracks make the perfect home for bugs, to avoid this, use a flexible sealant to block all possible entries, including roofs, joints, and individual logs.

Sand, varnish or paint your logs, this way they are not as attractive to pests such as beetles.

It is advisable not to use ground feed nearby your cabin to feed the local wildlife as it will encourage lots of critters.

Rodents typically like underground environments and may nest under floors or decking, steer clear of keeping vegetable patches in close proximity to your cabin as this will attract rodents and the like.

All in all…

If you follow all our advice, I can’t guarantee you won’t spot the odd critter but it will help you to avoid a huge infestation and to help you prevent one before it’s too late.

Remember, if you are reading this article before embarking upon building your log cabin, preventing unwanted bugs is much easier and quicker and usually more cost-effective than trying to remediate an infestation.

If you are reading this article in hope of gaining some advice as to how to eliminate an infestation then follow the above-remediating tips and let us know how it goes!

Have you ever experienced an infestation of unwanted bugs? What were the first signs you spotted? Did you manage to get rid of them? Share your stories with us below!


  • Good overview. I have powder post beetles in my 30 year old cabin. I individually spray insecticide into the new boreholes, every year. Seems to keep the number of active boreholes down.

    What I’m looking for is a method to inject borate into these boreholes, a little deeper, than just using an aerosol can. Aerosol cans with a thin plastic tube, work ok, but it’s kind of messy with some blowout after removing the tube from the borehole, and the plastic tube tends to work itself loose from the spray dispenser. I’ve thinking maybe something more like a syringe delivery, or preferable an aerosol delivery with a stout metal tube on the nozzle. The tube has to be very small diameter, about 1/32″, or possibly tapered at the tip.

    Just wondering if anyone knows of such a delivery system.

    • Hi Tom,

      I haven’t come across anything as such but I will leave your comment here in hope that someone can offer assistance.

      Many thanks,

    • Bit late to the party, but very easy to buy is “Borax” found in most laundry detergent asles. Borax, when mixed with real maple syrup will kill food ants. I would think you could add some water to it, and squirt it into any hole/tunnel. Might need to hunt for the right tubing to use, but it should do the trick!

      Borax is a chemical stable form of borate.

  • Looking to purchase a log home built in 2003. It appears it has never been maintained and the outside is infested with carpenter bees. Looks like some took an uzi to all sides of the house there’s so many boreholes. Before purchasing should this scare me off or a this typical and with lots of love get rid of the bees.

    • Hi Lee, thanks for your message. Ideally all cabins should be stained to prevent these types of infestations. However because it wasn’t stained or maintained for almost 20 years, I’d be quite cautious. You will be able to get rid of them, either using pesticides or naturally by blocking the holes up over the winter period. If you do choose to buy the cabin, after you’ve gotten rid of the infestation, apply stain and an exterior finish which has an oil or polyurethane base. Hope that helps! Thanks, David

  • Hello,
    I volunteer at a small nonprofit museum. We are located in a beautiful log building. Our problem is that the flies and stink bugs overwinter in the cracks outside and the woodpeckers are causing damage trying to get at them. Short of chinking, is there any ideas to repel the flys in the first place?
    Thanks for the help

    • Hi Beverly,
      They dislike strong smells such as mint, so you could try spraying diluted essential oils around the cracks. Make sure you keep the area dry as they are attracted to places with lots of moisture.
      Many thanks,

  • We have stained our log cottage with Sikkens Cetol Log and Siding finish, but some small holes have appeared from insections and we would like to apply something to get rid of the bugs and future infestations. They are not too many, but it is concerning. I have looked at Borate, but this is supposed to be for unstained logs. Other products provide relief for 4-6 weeks, but we would like something more long-lasting. What can you recommend?

    • Hi, Dan. I haven’t any experience with longer-lasting products – I’m not sure that there even are any. The main thing with infestations is to remove and prevent them either until that particular bug’s season has passed, or until they find somewhere else to go. Following best practices like inspecting firewood before bringing it back to the cabin, and storing it well away from the cabin, carry out regular inspections, and treat any holes that you find as quickly as possible to prevent the growth of a colony in your walls. Good luck, David.

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