Deck Building Codes: What Deck Screws Should You Use?

We've been building decks for almost 30 years, and we've learned what gets decks approved and what doesn't. As a contractor, you don't want to rip out finished work and rebuild it because inspectors red-tagged your fasteners.

Wrong screws or missing connections fail inspection, and you can't just patch the problem. You're pulling up deck boards and replacing entire ledger connections because the fasteners don't meet code, and that runs $2,500 to $8,000.

This guide shows exactly which screws IRC requires for each deck component so your deck passes inspection the first time.

TL;DR (What type of fasteners are required for deck construction?)

The types of fasteners that are required for deck construction are the following:

 

What Are the Most Common Fasteners Used for Constructing a Wood Deck?

The most common fasteners used for constructing a wood deck are nails, screws, and structural connectors.

But here's where it gets confusing. Building codes give you options, and not everyone agrees on which fastener works best for each job. Decking boards? That's one fastener. Joists to beams? Use something different. Ledger to the house? Totally different requirements.

What Deck Fasteners to Use To Avoid Common Deck Code Violations

Most deck code violations happen because people use the wrong fasteners. Building inspectors see the same mistakes over and over: nails where lag screws should be, deck screws in joist hangers, surface-mounted railing posts, and corroded fasteners in treated lumber.

These aren't just technicalities. 59% of building inspectors report seeing improper ledger connections, and 55% regularly find bad guardrail installations that could lead to deck collapse.

Here's the breakdown of the most common code violations and exactly which fasteners you need to avoid getting red-tagged.

Ledger Board Fasteners (Violation #1: Using Nails or Wrong Fasteners)

Wrong ledger fasteners cause the deck to rip off your house. Around 90% of deck collapses happen because the ledger connection failed.

IRC Section R507.2.2 and IBC Section 1604.8.3 ban nails and toenails for ledger boards. This has been in the code books since 2009, but inspectors still see nailed ledgers everywhere. 

The Violation:
People nail the ledger, use deck screws, or go with undersized lag screws. Sometimes they toenail at an angle, thinking it grips better. It doesn't work that way. Nails pull out from constant loading and deck movement.

The Fix:

You need to pick one of those options, and no substitutions are allowed.

• IRC requires ½" lag screws with 4" minimum embedment into solid rim.
• OR ½" through-bolts with washers on both sides
• OR ICC-ES approved structural screws.

The ledger carries the whole deck load where it meets the house. That connection breaks? You, your deck, and everyone are going down together.

Joist Hanger Fasteners (Violation #2: Using Deck Screws Instead of Nails)

You cannot use deck screws in joist hangers, even though they look like they'd work. Joist failures usually don't collapse the entire deck instantly, but they create holes people fall through.

IRC Section R507.6.1 requires joist hangers to be fastened with nails specified by the manufacturer, usually 10d x 1½" joist hanger nails.

The Violation:
People use deck screws or construction screws in joist hanger holes because they're easier to install than pounding nails. Problem is, deck screws are brittle under shear loads. They snap clean through even though they look totally fine on the surface.

You can have a joist hanger where every screw shank has snapped just below the head, leaving zero actual holding power, and you wouldn't know until the deck fails.

The Fix:
Use exactly what's stamped on the joist hanger:

• 10d x 1½" joist hanger nails for standard face-mount hangers
• #9 or #10 Strong-Drive SD screws only if specifically listed for that connector model
• Fill every single hole in the hanger because missing even one nail reduces the load rating.

Railing Post Fasteners (Violation #3: Surface-Mounting or Undersized Connections)

Railing failures happen when people lean on them during parties or gatherings. The posts either pull out completely, or the connection breaks and people fall over the edge.

IRC Section R312.2 and IBC Section 1607.8.1 require railing posts to resist a 200 lb. horizontal load at the top. Sounds simple, but here's the physics. A 200 lb. load on a 36" tall railing creates up to 1,500 lbs. of leverage force at the base connection.

The rail has to resist loads in any direction, not just outward pull but also inward push. The key word is "any direction" because people lean in all different ways.

The Violation:
People screw railing posts directly to the deck boards or use undersized lag screws that don't go through to solid framing. Surface-mounted posts have almost no resistance to horizontal loads, so they just rip out. This fails inspection immediately.

Tests on notched guard posts showed they can't meet the 200 lb. horizontal load required by code. For bolted deck rail posts without proper backing, connections failed at an average load of only 237 pounds. That barely passes code, and that's with new hardware. Over time, as connections loosen and hardware corrodes, that number drops.

The Fix:
Your railing posts must connect through the deck boards into solid framing with one of these options:

• ½" through-bolts with washers on both sides, going through rim joist and into blocking
• Hold-down tension devices rated for 1,500 lbs with specified fasteners
• Structural lag screws (½" diameter minimum, 4" embedment into framing)

Post Base Fasteners (Violation #4: Inadequate Lateral Restraint)

Posts that shift at the base compromise your deck's entire load path. Any lateral movement means loads don't transfer properly down to the footing, and you risk structural failure. Deck posts can slide due to soil erosion, poor drainage, incorrect footing installation, or natural soil movement on slopes.

IRC Section R407.3 requires posts to be "restrained to prevent lateral displacement at the bottom end." The code doesn't just say "anchored"; it specifically addresses lateral movement.

The Violation:
People set posts directly in concrete without mechanical anchors, or they use undersized post bases with inadequate fasteners. Sometimes posts sit on adjustable bases where the adjustment mechanism itself allows movement. Any connection where the post can shift horizontally under load fails code.

The Fix:
Use elevated post bases that keep wood off concrete and prevent lateral movement:

• Post bases (like Simpson ABU or equivalent) with ½" anchor bolts
• Anchor bolts must have a minimum 7" embedment into concrete.
• Hot-dipped galvanized or stainless steel coating required for ground contact

Lateral Load Connection Fasteners (Violation #5: Missing Tension Ties)

When people walk around on a deck, they create side-to-side movement that constantly works the ledger loose. Over time, this lateral movement causes the deck to pull away from the house, and that's when total deck failures happen.

IRC Section R507.9.2 requires decks to resist a 1,500 lb. lateral tension force at each end of the ledger. This prevents the deck from pulling away from the house.

The Violation:
Decks built without any lateral load connections, or with connections that don't meet the 1,500 lb. requirement. Older decks especially lack this because the lateral load requirement was only added to the IRC in 2009. Missing connections often mean the deck was held together with only nails, and toe-nailed connections can pull out.

The Fix:
IRC gives you two options:

• Option 1 (IRC Figure R507.9.2(1)):
  Install two 1,500 lb. hold-down tension devices, one within 24" of each end of the deck. Each device must use the exact fasteners specified in its ICC-ES evaluation report because you can't substitute generic screws.
• Option 2 (IRC Figure R507.9.2(2)):
  Install four 750 lb. hold-down devices evenly distributed along the deck, with the first device within 24" of each end. This option is better for retrofits because it distributes loads across more connection points.

Critical Code Detail:
IRC allows lateral connections to fasten into "top plates, studs, or headers within the supporting structure." You're not stuck connecting only to rim boards; you can go through sheathing into interior framing, which is often easier and stronger.

Decking Fastener Spacing (Violation #6: Wrong Spacing at Band Joist)

Board ends cup first and pulls away from the structure. Without proper 6-inch spacing at the rim, boards lift and water gets trapped in the gaps. Water can't drain properly, so you get a cycle where moisture stays trapped and causes wood rot.

IRC Section R507.7 requires two fasteners at each joist. But there's a second requirement people miss. IRC also requires deck boards to be fastened to the band joist at 6 inches on-center.

The Violation:
People install two screws per joist where deck boards cross. That part's fine. Then they skip the band joist requirement. The ends of deck boards need fasteners every 6 inches along the rim, not just two total per board. Wrong gap spacing between boards puts extra load on fasteners, leading to broken screws or nail pops.

The Fix:
Follow IRC spacing requirements:

• At joists: Two #8 screws minimum per joist crossing
• At band joist: #8 screws every 6 inches on-center along the rim
• Board spacing: 1/8 inch to 1/4 inch gaps between boards depending on material
• Coating: Hot-dipped galvanized or stainless steel for treated lumber per IRC Section R317.3.1

Board Spacing:
Use 1/8 inch to 1/4 inch spacing for deck boards. Kiln-dried wood needs 3/16 inch gaps for 4-inch boards and 1/4 inch for 6-inch boards. Pressure-treated boards should be installed tightly because they shrink as they dry, naturally creating about a 1/4 inch gap.

For treated lumber decking, use Eagle Claw stainless steel deck screws in 304 or 305 grade. When you're installing hundreds of screws across an entire deck, the Type 17 self-drilling point and T25 Torx drive head make a huge difference.

You won't spend hours pre-drilling holes, and the Torx drive won't strip out like Phillips heads do after driving screw after screw. Plus, stainless steel eliminates the rust staining that galvanized screws leave on deck boards after a few seasons.

Fastener Coating Requirements (Violation #7: Using Wrong Coatings on Treated Lumber)

As fasteners corrode, they lose holding power. Deck boards start working loose because corroded screws can't maintain clamping force. You end up needing to replace hundreds of fasteners on a deck that's only a few years old.

IRC Section R317.3.1 is specific: "Fasteners for pressure-preservative and fire-retardant-treated wood shall be of hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze, or copper."

The Violation:
People use electroplated zinc screws, regular construction screws, or bright uncoated nails on treated lumber. These fasteners corrode rapidly in treated wood, leaving rust stains and loose connections. Electroplated zinc looks similar to hot-dipped galvanized but fails way faster.

The Fix:
Use IRC-compliant coatings:

• Structural connections: ZMAX coating minimum
• Treated lumber anywhere: Hot-dipped galvanized or stainless steel
• High-corrosion coastal environments: Grade 316 stainless steel

Eagle Claw stainless steel fasteners in 304, 305, and 316 grades exceed IRC coating requirements by using solid stainless steel throughout, not just a surface coating. No coating can wear off or get damaged during installation, providing permanent corrosion protection. This eliminates rust stains, loose connections, and the need to replace corroded fasteners years later.

The Best Code-Compliant Stainless Steel Deck Screws

Eagle Claw isn't just the best stainless steel deck screw; it's also code-compliant.

Eagle Claw deck screws meet IRC Section R317.3.1 coating requirements for pressure-treated lumber using solid stainless steel throughout, not just a surface coating. 

For coastal decks within 300 feet of saltwater, Eagle Claw 316 marine-grade stainless steel screws provide superior corrosion resistance compared to any coated fastener.

Professional contractors and DIY builders choose Eagle Claw because they get Simpson Strong-Tie quality at a price that makes sense for entire deck projects. No rust stains, no stripped heads, and no replacing corroded fasteners years later.

Building multiple decks? Sign up as a deck builder and get 10% off every order. When you're buying fasteners by the thousands for multiple projects, that discount adds up fast. This rate won't last forever!