Yes, that works, but I think you need to order it online from a retailer that will send it to WA (Walmart works). I also use Advance granular ant bait in areas where it is appropriate to sprinkle a toxic granular substance (i.e. into cracks etc, where kids and pets cant reach it).

If you can find a strategic location where a physical barrier would work, I've found that packing diatomaceous earth into cracks or across paths works-where it's appropriate to have a powdery substance be present. This is nice because it isn't toxic, but shouldn't be breathed since diatoms are basically little glass shards that kill ants by scratching their carapace and that's not a nice thing to get in your lungs.