I have an exterior french door leading to a fiberglass deck over a room and have water leaking into the room when it rains heavily

Where is water coming in? Under saddle? Under doors? Sides of doors? Between doors?

If under saddle, seal with silicone. Go up sides of jamb trim about a foot.

If through sides of doors or between, doors need to be adjusted to sit tight together. Through the sides , doors need to be set tighter to door stop.

Good luck

Chuck

If under doors, the weather proof saddle has to be adjusted or replaced.