I am framing a deck around a cantilevered fireplace chase. The old deck ledger was attached to the chase, which I have removed so there is no siding there, only sheathing. I am going to frame around the chase as in the picture below so there will be no new ledger attached on the chase.

What kind of flashing should I use around the chase behind the deck frame (behind the header and trimmer joists)? It needs to be something that wont break if it's poked with a stick or kicked by kids, is UV proof, and won't corrode from the ACQ treated wood. It will be exposed for a few inches above decking level.

I am thinking about starting it 6" behind the ledger on left then wrap a single piece around the chase and end it 6" behind the ledger on the other side. Then of course put more flashing over the top of the ledger.

But how should it be fastened? Can I nail it on with stainless steel nails and caulk over the heads? Or glue it on? There will be a vycor backup flashing behind.

{{!gwi}}