Decks, Patios, Porches and Docks - Siding at Ledger Board

House has aluminum siding and adding a ledger board. Removed siding to install ledger, top of ledger falls in the middle of siding. What is the best practice to trim out the siding considering thjat the siding is aluminum and there is no starter strip or j-channel. Look forward to some advise.

First off, I would have made the deck free-standing. No need to disturb the siding.

But, seeing as how you ready all did that, you will need to use a J-channel around the deck, then slip the siding into it. Starter is out of the question -- you don't have the hook on the siding to attach to the starter.

I just did the same thing. I have aluminum siding, and attached the ledger. I used flashing from HD, it is pre-shaped to rest on top of the 2x ledger, and the long edge slides up under the siding. I cut the bottom 2 rows of the siding from underneath with a sawz-all. The bottom of the siding was loose, but not too bad. After sliding the flashing up underneath it, and then attaching the ledger, it isn't loose at all. On the ends of the cut siding, I used pieces of flashing to fill in the gaps. It doesn't look unfinished, you almost wouldn't even know I cut away the siding. I think where I got lucky is how the ledger sat in relation to the siding. It was at the bottom of one course of siding, and the top of the other (course is 2 rows).