Caulking & Sealing
There are two types of caulking that can be put on the outside of your home in order to seal it from weather, air conditioning, heat loss, and insects. They both also protect the wood and substrates on both the inside and outside of the home.
The first type of caulk is latex caulking; it's the most widely used caulking product on the outside of a home. With a good top brand caulking material, once it dries, it will have a 50% elasticity rate; which means when the home gets hot or cold, it'll stretch with those temps. The other advantage to latex caulk is that once it's applied to any surface, and it has bonded and dried, it can be painted any color, so that the final look is a smooth seamless seal between painted surfaces. Once you paint over the caulking, it's sealed up and solid, but leaves everything secure and tight.
The second type of caulking that can be used is a silicone based caulk; this type of caulking dries clear and can be used around brick, windows, and other surfaces you may not be painting. Silicone based caulking is good and firm, and seals very well against drafts, insects and weather. However, it doesn't stretch as much as latex caulk, it's designed to fill in surfaces that don't move as much like masonry brick, windows, and metal.