The notice shows the club is seeking to demolish the main East Stand structure, which ends at the players' tunnel.
The media centre, former supporters club building, toilet block and most of the terracing to the left of the main building will be demolished.
The concrete structure to the right of the main stand, which houses the players’ changing rooms and tunnel, will remain but the roof will be removed as well as some of the terrace area at the front of that section.
The application is still pending consideration by Watford Borough Council and the club has indicated it hopes to begin the demolition on August 19 and expects work to be completed by September 30.
The club’s application confirms the demolition work is “in preparation for construction of a new structure”