[header] How to caulk [title] Use silicone caulk if you need a neutral-colored waterproof sealant. [step] There are two main types of caulk-silicone and acrylic latex. Silicone caulk is a completely waterproof and flexible sealant. 
It will bond with a lot of different kinds of surfaces. Silicone is a good choice if you're caulking outdoors, or wet indoor spots like around shower stalls and bathtubs.