Aim a garden water hose with a sprayer set on mist or low at the outside of the sliding door.
Leaking above sliding glass door.
With such strong requirements if you are still finding water intrusion after general maintenance and a weatherstripping installation your sliding glass doors or impact windows may not be properly installed.
Glass door window installation due to florida hurricane codes sliding doors must have a 1 5 3 5 inch water threshold dam.
Brush fin or fin seal type weather stripping installed between sliding doors reduces energy loss and helps to.
The ultimate goal is to create a series of overlapping layers of flashing material so that any water that gets behind the door trim from above the door or along the sides is captured and redirected.
You can do this by taking steps to make the bottom of the door frame waterproof before you install the door.
The best way to stop the leaks is to prevent them from occurring in the first place.
Note that if the sliding glass door leak you described has already worked its way under any adjacent exterior siding you ll likely have to remove and reapply that siding as well in order to install the new material and repair the leaking sliding glass door but the extra effort will be well worth it the next time coastal winds blow rain your way.
If you cannot re create the leak problem inspect the interior of the door for stains or rust.