To seal the seam between a doubled joist or beam, what type of caulking is best? The Home Depot Decks 123 book recommends Alex Plus (acrylic latex plus silicone) while a guy at Home Depot suggested Mono Ultra Exterior (latex). How about Blueskin?
I initially used Alex Plus, it rained before the caulk cured, the caulk became a shriveled and cracked mess, I scraped it and replaced it with Mono Ultra Exterior.