Part of the challenge of doing something you’ve never done before is discovering the mistakes you’re making along the way. And in the best of cases, they’re not irreversible. While feeling blessed with the mildest November weather we’ve had since, apparently, 1946, I discovered something unforeseen (for me, anyway) about the contact between ACQ pressure treated lumber, which I’ve been using to anchor the base of the arches and endwalls, and Galvalume, the stuff of which the metal panels are made (Aluminum-zinc coated-steel). Alkaline Copper Quartenary (ACQ) pressure treated lumber contains (surprise!) copper which, according to the Metal Construction Association, when in contact with aluminum “in a wet environment, these dissimilar metals create a small electric current which triggers a chemical reaction resulting in GALVANIC CORROSION.” (emphasis mine)
So, basically, I’d been setting up our Tiny House of Steel to very quickly rot.
Needless to say, this sent me spinning, wondering whether I’d have to replace all the wood and basically start from scratch. Luckily, I have a very smart cousin who suggested a combination of rubber sealant spray on the surface of the Galvaume with a foam sill sealer over the pressure treated wood which would create enough of a barrier so as to avoid contact between the two. This gives you an idea of what that process was like:
STEP 1: unbolt and jack up the base plate off the trailer
STEP 2: spray rubber sealant on the underside of the base plate
STEP 3: lay sill sealer over wood base
STEP 4: drop the whole damn thing and walk away before anyone gets hurt. And breathe.
Easy! Well, not really. But it does make me think twice now every time I get to a place where I know I’ll be putting two different materials together: “Do they like each other?”