No Worms in the Loft!

The loft joists were one of the first interior structural components that I added to my house. Pretty soon, though, I realized that those joists would just be in the way until I installed a floor over them.

Plywood? Meh. Store-bought decking? Maybe. Hardwood floorboards? Probably too thin unless I lay down a plywood subfloor, and then I'll be staring at plywood from my bed underneath--nah.

But then I learned that my Uncle Chuck had in his keeping a pile of gorgeous 1 1/4" thick, 13-15" wide pine boards that had been ripped out of the floor of a church in Oregon. History, character, conservation of resources!

Hard work!

Reclaimed materials are always going to take more work than newly manufactured ones. How much more depends on how perfect you want the final appearance to be--for me, not a huge priority, because "rustic." It also depends on the condition of the materials you're starting with.

I headed over to my uncle's house with a few chickens to trade (fair's fair), Dad and I strapped a few of the boards to the top of the Sienna, and we trundled home with them.

Then, at some point after getting home with the boards, I noticed some funny little tunnels bored into the wood. Hmm. A spot of Googling revealed that those old church floor boards had--at some point in the past or present--a woodworm infestation.

The condition of the materials you're starting with... sigh.

Woodworms are the larvae of wood boring beetles, a general classification that includes several species of beetle that--surprise, surprise--bore into, eat, and lay eggs in the wood of dead and moribund trees. (Wood boring beetles attack both lumber and forest trees. Bark beetles are another type of beetle that can kill living trees--and do, now at hugely increased rates as their habitat warms and more of them survive the once-killing winters.)

Woodworms are a bad thing to have gnawing at your structure, so there's plenty of advice out there for eradicating them.  Heat and hydrogen peroxide were the two most feasible solutions I found, both of which I ended up trying.

My first solution, though, was to cut off as much of the most badly infested wood as possible. Thankfully, I didn't need every single boardfoot of pine that I'd brought home--this piece could stand to be narrower, that piece could be cut to length so the riddled middle was the waste end, rather than an actual end. It was during this step that I found a live-and-kicking woodworm, so I knew a more intensive treatment was required.

The first treatment I tried was heat. I decided to shou sugi ban the undersides of the planks, to make the planks fit the theme in the bedroom area and to see whether the torch would heat the wood enough to kill the worms. I don't know if it was the age of the wood, the high moisture content, or what, but it did not want to burn... and when the time came to scrub off the char, it wanted even less to scrub clean. But if I was having a bad day with it, someone else was having an even worse one: at least one worm got toasted. I found it  at the mouth of a tunnel while trying to scrub the burned wood. It looked like it had felt the inhospitable heating of its home and tried to escape... insert adage about frying pans and fires.

Heating woodworm infested pine to kill the larvae (hopefully!)

However, during the burning process I held my hand to the opposite side of the wood and it was definitely not heating all the way through. Plus, the recommendation I read was to raise the temperature of the wood to about 125-130ºF for eight hours. I decided to use a heat lamp to heat sections of the planks, concentrating on the areas with the most holes and sheltering the section with a cardboard box. I doubt I got the temperature into the bug-killing range throughout the entire thickness of the wood, but I at least got the surface hot enough for long enough.

Injecting hydrogen peroxide into woodworm holes

Next, it was hydrogen peroxide's turn. If I remember correctly, this was Uncle Chuck's suggestion. The hydrogen peroxide I used was the normal, 3% concentration, first aid kit type. It's not all that poisonous in itself... at least, not to a human, though a larva might beg to differ!

I used a syringe to inject the hydrogen peroxide into the holes, and then watched as eggs and frass (bug leavings) bubbled out. At least, I hope some of those tiny pellets were eggs...

Hydrogen peroxide bubbling out woodworm frass and eggs

The only way to test if any of these methods really eradicated the woodworms is to wait and watch for the telltale little piles of sawdust. If the heat and hydrogen peroxide fail, if the drying of the wood in the indoors climate fails to make the boards inhospitable to the larvae, then I will have to move on to a harsher treatment like boron.

For the time being, though, the boards are in place and (except in the two spots where boards meet end-to-end without a supporting joist) the loft is now a walk-on-able surface. Hurray!