Caulking is a material used to seal gaps and joints in various structures, such as buildings and plumbing. It helps prevent air, water, and dust from entering or escaping, improving energy efficiency and protecting against moisture damage. Common types of caulk include silicone, latex, and polyurethane, each suited for different applications. Applying caulk typically involves cleaning the area, using a caulking gun to dispense the material, and smoothing it out for a neat finish. Properly applied caulking can extend the lifespan of windows, doors, and other fixtures by reducing wear and tear from environmental factors.