How do I secure the ledger board when the siding is already up?

Cutting vinyl that's alredy on the wall is easiest with a circular saw or an angle grinder, but you have to flip the blade around so it's running backward. This prevents the teeth from grabbing the plastic and shattering it, expecially if it's cold out. You want to snap a chalk line where the top of your ledger board will sit, then cut about an inch or two higher than that to give yourself room for the Z-flashing. Don't worry about the water barrier too much yet; you can repair any minor nicks with high-quality flashing tape before you bolt the wood to the rim joist. You absolutely need to use **ledger tape** or a similar bituminous membrane behind the board itself. Since the siding is already up, you'll need to tuck a wide strip of flashing under the remaining vinyl above the cut so it sheds water over the top of the ledger. If you just bolt the board over the siding or skip the flashing, water will eventually find its way into your house's framing and rot out the floor joists. It's a bit of a pain to retro-fit it now, but it's the only way to keep it watertight.

For the actual attachment, make sure you're using structural screws like LedgerLoks instead of old-school lag bolts. They don't require pre-drilling and hold better over time. Since you mentioned the French doors are already there, make sure your ledger is sitting low enugh that your decking will end up about an inch or two below the door threshold. This prevents rain from splashing back and getting under the door sill during heavy storms.

Once the ledger is secure and flashed, you can hide the cut edges of the vinyl with J-channel. It snaps right in and gives it that finished look so it doesn't matter if your cut wasn't 100% perfect. It feels like you did it backward, but honestly, people have to redo decks on finished houses all the time. Just take it slow with the saw and focus on that **Z-flashing** at the top.

That backward blade trick is the only way to go if you want to avoid those ugly jagged cracks. Just a quick heads-up though: when you're sliding that Z-flashing up, make sure it acutally gets tucked behind the house wrap layer, not just behind the vinyl siding panels. If it’s just under the siding, water can still migrate behind the moisture barrier and rot your sheathing from the inside out.

I'd also suggest hitting the back of your ledger board with a wood preservative or end-grain sealer before you bolt it up. Since you're dealing with a second-story drop, you relly don't want to be pulling this apart in ten years becasue of preventable rot.

This is so awesome to read through! I'm finally getting my tools togehter for a small porch build next month and I'm super pumped. Those French doors hanging over the edge whould give me such a rush every time I walked near them, haha! Quick question for the group though—since you’ve got everythign out on the gravel allready, what are you guys doing for the stairs? I'm debating between those pre-cut stringers or trying to cut my own, but I'm worried I'll mess up the math and end up with a trip hazard!