Final answer:
Exterior-grade caulk is used as a sealant to protect joints where siding meets horizontal surfaces, ensuring durability against the elements and water ingress.
Step-by-step explanation:
Sealant is a substance used to block the passage of fluids through openings in materials, a type of mechanical seal. In building construction sealant is sometimes synonymous with caulk (especially if acrylic latex or polyurethane based) and also serve the purposes of blocking dust, sound and heat transmission.
In regard to siding, a sealant is typically used to seal the joints where the siding meets a horizontal surface. This sealant is usually a high-quality, exterior-grade caulk designed for durability and to withstand the elements. When applying caulking, it is important to clean the area thoroughly, remove any old caulk, and ensure the surface is dry before application. Afterward, the caulk is applied and smoothed to create a waterproof barrier that prevents water ingress and helps maintain the integrity of both the siding and the structure.