How to Evict Wood-Be Guests

Termites aren’t welcome on a boat. Here’s how to get rid of them.


Last summer, I found evidence of guests most undesirable on my boat. They were careless, leaving holes in my walls and making messes throughout my boat. Termites are the worst guests.

Initially, I noticed a few droppings in the main salon. Then, just as my luck goes, Madam Admiral (my wife) found some dead termites. I had to act quickly to shorten their stay aboard.

Eye Eye, Captain

Termites use tunnels to move through wood, and they create pinholes to remove their droppings from the tunnels. Wherever you see termite droppings, you should closely inspect the nearby wood. Use a screwdriver handle or a small hammer to gently tap along the wood. You will be able to feel and/or hear a difference between solid wood and hollow areas where termites have tunneled. Look for bulging wallpaper or buckling wood, and use a flashlight to look into crevices for signs of termites.

Use a flashlight to look into crevices for signs of termites.

Use a flashlight to look into crevices for signs of termites.

Lethal Weapons

Online, I found the Structural Pest Control Fact Sheet on Termites, published by the state of California’s Department of Consumer Affairs. The document stated, “Fumigation and heating … are the only options that ensure eradication in the entire structure.”

Fumigation disperses chemicals, generally called termite insecticide, or termicide, into a structure wrapped with tarps, vinyl or other materials. The airtight exterior wrapping forces the termicide into every nook and cranny of the structure.

The heating method employs the same exterior tenting but uses equipment to force hot air into the interior. The Structural Pest Control Fact Sheet recommended that wood should be heated to 120 degrees Fahrenheit to kill termites.

Foam Home

Before fumigation and heating, I injected termicide foam directly into droppings holes, using a straw applicator. The straw should fit snugly into the holes. If necessary, use a small drill bit or wood screw to slightly expand the holes. Spray the foam in each hole until it overflows from the original hole or another one. You should also drill holes and spray foam into hollow wood areas. Be sure to use protective eyewear and gloves when handling and applying it.

Using a straw applicator to inject termicide foam into holes is a good first step before fumigation.

Using a straw applicator to inject termicide foam into holes is a good first step before fumigation.

Bombs Away

Next, I used a bug bomb to kill any termites living in the headliner. There are two types of bug bombs: foggers and fumigators. Foggers disperse liquid termicide into open spaces but do not penetrate into voids and inaccessible spaces, which is what gaseous fumigators do. I used three fumigators, as calculated for the interior size of my boat. I did not tent my boat, but I did make sure all the windows and hatches were closed tightly.

When I returned to the boat, I opened all the windows and aired it out for a few hours before boarding. Since part of the headliner was previously damaged, I decided to remove it, along with the backing plywood and the overhead insulation. I found several small nests of dead termites and significant wood damage, so my next project is to replace the headliner with PVC beadboard.

Before you use bug bombs, be sure to read the product’s instructions and safety information carefully. Do not use more than is recommended for the interior square footage and don’t place them in small spaces such as a cabinet or a closet or under a table. Leave interior doors open so the product can expand from one room to another. As an extra precaution, disconnect your batteries and shore-power cable while the bug bomb is deployed, to avoid accidental ignition of the termicide or its dispersing propellant.

Heat It Up

Before starting the heat treatment, I removed almost everything from the boat, including appliances, bedding, computer equipment, cushions, DVDs, furniture and anything else that might be susceptible to heat damage. Then I removed all the window covers and curtains, to let Mother Nature have full access to the interior to work her solar magic.

During the summer, Southern California had weeks of 90- and 100-degree days. While I can’t definitively say the interior wood reached 120 degrees, I figure the high temperatures sustained for longer periods of time killed any termites that survived the foam and fumigator treatments.

For the first few days, I vacuumed enough dead termites to repeatedly fill a red Solo cup. Although this was a disgusting waste of a perfectly good drinking vessel, it quantified my success for Madam Admiral — much to her dismay. By the end of the week, I didn’t find any termites. For now, I think I have successfully evicted them. I don’t think they will be visiting any time soon, but I will still do another treatment in the early spring.

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