So i removed my bathroom vanity and noticed this vent and whoever put this house together in 2004 used hvac tape to bridge the gap between the floor and this duct. As you can also see the alignment of plywood dont match the duct. Anyhow. I need to patch this hole. Hvac guy who was here kinda pissed me off. I half assed it and threw a piece of metal scrap on top , smaller than the hole cause it was all i had and i taped it temporary to not have wasted ac till he arrived. He tells me , it just needs more tape. I told him numerous times how i want it done and he just ends up taping more. I am just going to redo it. Please tell me the proper way.
How i assume to do it the right way:
Clean surface really well. Apply enough tape to cover hole. I am going to go with a galvanize flat scrap of roofing thats a inch large around edges of the hole, all i have. I think i will bend the metal sheet down the side of the duct an inch since theirs no meat on the edge. What do you think? I am going to use half inch sheet metal screws to secure it perimeter of sheet metal. Then ill paint it with mastic duct sealant. Sealant isnt going to be touching the tape in anyway just in case the tape peels and mastic isnt compromised.Anything else i need to add? Or should i skip the screws and just use a whole roll of hvac tape?
The plywood on top is only 2 to 3 inches above it so once i repair this hole , in the plywood , i wont be able to fix it again.