Also, disodium octaborate tetrahydrate (aka Tim-Bor / Bora-Care in the US). Roughly: glycol + borax + boric acid. Spray it on lumber, and it absorbs into the w

Also, disodium octaborate tetrahydrate (aka Tim-Bor / Bora-Care in the US). Roughly: glycol + borax + boric acid. Spray it on lumber, and it absorbs into the wood, killing termites, powder post beetles, carpenter ants, mold, and algae. For the lifetime of the lumber, no reapplication necessary. Cannot recommend it highly enough for exposed crawlspaces / basements in humid climates.