The wall of my bathtub was cut too short when installed and water leaks to downstairs when I take a shower if it gets into the space between the tub and the wall. My father has tried caulking and even gorilla gluing these white strips there but it still leaves a space. How can I fix it?
Depending how badly it was cut, sometimes the only complete solution is a new tub. At minimum, you need to re-cover the wall so that water on the wall runs into the tub - this may require new tiling or a tub surround. Any time a tub is replaced, the walls around the tub need to be done over, or leaks are almost guaranteed. The image is from a ceramic tile site, but the general idea is the same regardless of material - the wall must overlap the tub.