First check whether the drain is running freely. If that is not the case, you first have to clear it or call in a professional drain unblocking firm.

The drain is clear but still leaks? You can repair a major leak or crack with WP7-202 Roof Tape. This can be done on the inside or outside. In any case, make sure the surface is clean and completely dry!

Tec7 Roof Tape
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