Most chicken coops are made of wood, and all wood eventually rots. You can deal with this fact in a number of ways:
- Build with wood that’s infused with pesticides (pressure-treated “PT”)
- Use a naturally rot-resistant wood (like cedar, redwood, or tropical hardwoods)
- Choose a softwood (like Douglas-fir, hemlock, or pine) and apply a sealer
- Use a composite material instead of wood
Many factors will weigh into your choice, but I’ll deal with the two biggies: toxicity and cost.
Anything that’s put into or onto wood may find its way into your chickens, then into you. So you might want to be cautious about using pressure-treated wood. Its biggest advantages are longevity and cost. Its disadvantages include: leaching of copper and *potentially* harmful stuff into the soil where your chickens will be; you need fasteners that won’t be easily corroded by the copper in the wood; you need to re-treat at every cut to ensure complete coverage.
I say “potentially harmful” above, because the preservative treatment currently used in PT (Alkaline Copper Quat, or ACQ) is said to be safer than the stuff they used to use (Chromated Copper Arsenate, or CCA) in that it doesn’t contain arsenic. The EPA still advises against using any kind of PT “in circumstances where the preservative may become a component of food, animal feed, or beehives.” So if you’re a farmer, your operation can’t be certified organic if you use PT — even the newer kind. That doesn’t mean that PT has been proven harmful, only that it has not been specifically proven to be safe.
So I wouldn’t absolutely rule it out, particularly if you’re in a humid or termite-prone area, but do consider all your options.
As for sealers, choose carefully to avoid toxic ingredients. Personally, I like the products from TimberPro Coatings. Green Depot offers some safe options for exterior use, including the brand Osmo. Finally, using naturally rot-resistant woods gets you around the toxicity problem altogether, but leads to the second issue. . .
Let’s start with cedar. It’s pricey, and while praised for its rot-resistance, this characteristic is true more of the heartwood than the sapwood. Two local lumber stores told me that most available cedar comes from second-generation forests and lacks the longevity of old-growth heartwood. Both steered me away from it, saying that you’d have to seal it, and if you’re sealing it anyway, you might as well use cheaper softwood. Other costly options include the composite material used for decks and FSC-certified tropical hardwoods, both of which are more expensive than cedar, yet can last unsealed for decades.
The best choice?
I’m not sure. But I can share some principles:
- Mix materials based on how exposed they’ll be in your finished product, investing in longer-lasting materials where it pays to do so.
- Remember that once you attach hardware cloth to the wood, you will likely never get the chance to seal it properly again.
- Use a non-toxic preservative such as Internal Wood Stabilizer from TimberPro UV on any unsealed softwoods.
- Build so that you can replace pieces without having to dismantle the whole coop. This way, a rotten board every few years isn’t such a big deal.
- Remember that the best wood may be what you can reclaim from another project. Make sure it is free of toxic paint, seal it up, and you’re good to go.
- The perfect is the enemy of the good. Don’t let your search for the ideal materials or design get in the way of building something. After all, it’s just a chicken coop!