You found a guy to build your deck. He showed you a picture of a nice deck he did somewhere in New Jersey, gave you a price that felt reasonable, and now he’s out back swinging a hammer. Great. But here’s what nobody told you before you signed the contract: when the inspector comes out, he’s not looking at your deck boards or your railing posts or whether the whole thing looks nice. He’s looking at your hardware.

Joist hangers. Ledger bolts. Joist spacing. Fastener specs. That’s what fails inspections. And when it fails, it’s not the contractor who has to live with it. It’s you.

So let’s go through what actually matters.

Your Ledger Attachment Is the First Thing They’ll Scrutinize

The ledger board is the piece that connects your deck to the house. It carries a significant share of the load. Get this wrong and your deck doesn’t just fail inspection — it can fail structurally, which means the whole thing pulls away from the house. That has happened. People have died.

For a ledger attachment to pass inspection, it needs to be bolted — not screwed, not nailed, bolted — through the house rim joist into solid framing, with specific bolt diameter, spacing, and pattern depending on your deck’s dimensions and local code. In most jurisdictions that means half-inch or five-eighths-inch through-bolts or structural lag screws at a specific pattern. Your inspector knows exactly what that pattern needs to be, because it’s in the code book.

One more thing on ledgers: the flashing. If there’s no flashing where the ledger meets the house, water will get behind it, rot the rim joist, and eventually the whole connection is compromised — inspector or no inspector. Flashing isn’t optional. It’s part of the spec.

Joist Hangers: Right Product, Right Fasteners, Installed Correctly

This is where I see the most cheap-out behavior from low-bid contractors. They grab whatever hanger happens to be in the truck — wrong size, wrong load rating, sometimes a different manufacturer than the spec calls for — and nail it in with whatever they’ve got.

That is not how this works.

Every joist hanger has an approved fastener list. It’s printed on the hanger packaging and published by the manufacturer. If the spec calls for Simpson Strong-Tie LUS28 hangers with 10d x 1.5“ joist hanger nails, that’s what gets used. Not drywall screws. Not 16d sinkers. Not “close enough” nails from a bucket in the garage. The manufacturer tests their hangers with specific fasteners to get their published load ratings. Substitute the fastener, and the rated load no longer applies — and your inspector knows this.

Same goes for the installation. Every hole in that hanger gets a nail. Every single one. I’ve seen guys fill maybe half the holes because it was faster. Inspector catches that, the whole section comes down.

Joist Spacing Is Not a Suggestion

Sixteen inches on center. Twelve inches on center. Sometimes twenty-four for certain spans and lumber sizes. Whatever the plan calls for, that’s the number — measured from the center of one joist to the center of the next, consistently, across the entire deck.

Why does this matter? Because the deck boards spanning between joists are rated for specific spans. If the spacing is off — say you’ve got some joists at eighteen inches because the crew rushed — your decking may not be rated for that span. It’s also a load distribution issue. The math on beam sizing and post loads assumes consistent joist spacing. Drift from that and your structural calculations don’t hold.

I had a job years back, a customer in South Philly called me in after a previous contractor walked off the project. We opened up the subfloor framing on what was supposed to be a straightforward deck expansion and found joist spacing that looked like it was measured with a ruler that had been dropped down a flight of stairs. Twelve, seventeen, fourteen, twenty-one — all over the place. Every hanger had to come off. We reframed the whole thing from scratch. Cost the homeowner almost double what it should have because they went with somebody cheaper the first time.

Don’t Mix Hardware Brands and Don’t Skip the Specs

This one is simple but people get tripped up by it. Structural connectors — hangers, post bases, beam seats, angle brackets — are engineered systems. When a manufacturer rates their hardware, that rating assumes you’re using their product as a complete system. Mix brands and the load-transfer assumptions break down. An inspector trained on this stuff will flag it.

Same goes for skipping specs entirely. Some contractors wing it. They’ve built decks before and they know what looks solid. That’s not what the code cares about. The code has specific requirements for fastener size, connector type, and installation method for a reason — because decks are structural elements that carry real loads, and when they fail, they fail fast.

The Bottom Line Before the Inspector Arrives

Before anyone closes anything in or lays a single deck board, ask your contractor three questions:

First, what are the ledger attachment requirements for this project? Can you show me the bolt pattern on paper?

Second, what joist hangers are we using and what fasteners are approved for them?

Third, are we getting a framing inspection before we deck over?

If they can’t answer the first two, they’re guessing. If the answer to the third is “we don’t need that,” they’re cutting corners. A framing inspection happens before the decking goes down so the inspector can actually see the hardware and the structure. Once the boards are down, he can’t. Some contractors use this as an excuse to bury work that wouldn’t pass.

Get the inspection. It exists to protect you.