It also needs to be waterproof and mold and mildew ... where weather and waterproofing is a factor, silicone or Butyl rubber ...

That's why learning how to waterproof it with silicone sealant is such a game-changer ... it's essential to do some prep work to get the best results. Rushing through the process might mean ...

Over at The Home Depot, a search for the "best rated caulk" currently shows Gorilla Waterproof Caulk & Seal as the one with the most positive reviews. GE and Locktite brands also feature strongly.