There are countless videos online that show you how to install these flashings under a door or window.
How to fix sliding door water leak.
Weatherstripping and flashing are rubber insulators located on the.
Cover the bottom of the side jamb with the tape.
There are preformed plastic flashing pans that you can use under the door or you can create one with thin sheets of lead or modern rubberized asphalt based flashing tape.
Place the end of a strip of adhesive backed aluminum tape on one of the side jambs in the doorway 3 inches above the threshold.
Check the weatherstripping or flashing.
If you have a water leak at your threshold you must watch this how.
How to stop water leaks under a door frame.
How to fix a sliding door leak.
There are pre formed plastic flashing pans that you can use under the door or you can create one with thin sheets of lead or the modern rubberized asphalt based flashing tape.
Test the door for the location of the leak.