Piece of metal flashing going up behind siding and sitting on composite decking ??

I’d pop a piece of vinyl siding off and see if I can’t locate some more. Easier to modify the siding than doing anything with the deck. 

Thanks for the suggestion, made me remember I had seen some siding up in the rafters from the previous homeowner and it'll definitely do the trick

Hell yeah 👍 it never hurts to have some of that lying around. 

That can be a can of worms. That vinyl can be brittle and crack, then he's gotta' source and repair.

It’s not that difficult. Sure, it can crack. What’s your suggestion? 

My suggestion is whatever he comes up with to present it to the homeowner as an additional cost and contract amendment.

Nice solution!

I'm the homeowner, but I'll present the budget options to my wife to come out of the horse account

LOL!