a skilled handyman carefully applies clear sealant along the gap between the bathtub and wall tiles using a caulking gun. The thick, smooth substance fills the empty space as he moves the tool steadily along the joint. Before the sealant application, water droplets were seeping through the cracks onto the floor. Now the gap becomes completely sealed as the protective material hardens in place. A homeowner watches nearby, holding towels and pointing to other areas that need attention. a substance being used to seal gaps and joints to prevent leakage of fluids