Work on a joint can refer to the job of caulking, which is the process of filling in gaps or cracks in a surface with a sealant. Caulking is often used to fill in the gaps between two surfaces, such as between tiles or between a window frame and a wall. It is also used to seal joints in pipes and other plumbing fixtures. Caulking is an important part of many construction and renovation projects, as it helps to prevent water damage and air leaks.