Joist Hanger Screws vs Nails: What Code Requires

Most DIYers get this wrong: you cannot use standard screws or drywall screws in joist hangers. The IRC building code is specific about fastener type for structural connectors. Here is exactly what is required.

The Code Requirement

IRC Section R802.3 and IBC Section 2304.9 require that structural connector fasteners be installed per the manufacturer's ICC-ES evaluation report (ESR). For Simpson Strong-Tie hangers, that means:

• 10d common nails (0.148" diameter x 1-1/2" long) for most standard hangers
• Simpson Strong-Drive SD connector screws (1-1/2" or 3") where screws are specified
• Never drywall screws, deck screws, or standard wood screws

Why Regular Screws Fail in Hangers

Joist hangers are loaded primarily in shear — the fastener resists the joist being pulled downward. Screws resist tension (pulling out) well but have poor shear strength compared to nails of the same diameter. A drywall screw in a joist hanger can snap under shear load at a fraction of the rated capacity. This is why the code specifically requires the fastener type listed in the ESR report.

Hanger Nail vs Hanger Screw Comparison

Hanger Nail Sizes Quick Reference

• 1-1/2" x 0.148" (10d Short): Standard for most face-mount hangers — LUS, LUS-SDS, HUS series
• 3" x 0.131" (16d Sinker): For top-flange connections and heavy hangers
• 1-1/2" x 0.131": For lighter hangers and sloped connectors
• Joist hanger nails (short): Pre-packaged specifically for hanger holes — do not substitute

Can I Use Screws Instead of Nails in Joist Hangers?

Yes — but only Simpson Strong-Drive SD screws or equivalent connector screws listed in the hanger ESR report. The ESR report for each Simpson product lists approved fasteners and the load values you get with each. Where a hanger’s ESR lists both, the SD screw and the 10d nail carry their own published load values — sometimes equal, sometimes not, and the report is what settles it. SD screws are the practical choice when a nail gun is not available, but “screws are stronger” is not a rule you can apply across hangers.

Never substitute standard wood screws, deck screws, or drywall screws regardless of length or gauge. These are not rated for shear in structural connectors and will fail under load.

The Coating Has to Match the Hanger

Getting the fastener type right is only half of it. The fastener finish has to match the hanger finish, and this is where most exterior joist hanger installations quietly go wrong.

The common failure: a plain G90 hanger bought off the shelf and used on a pressure-treated deck. G90 is the interior standard and is not rated for contact with ACQ-treated lumber — it can corrode through in roughly three to seven years outdoors. A silver, shiny hanger with no ZMAX stamp is the wrong part for a deck, and no fastener choice compensates for it.

Modern treatments made this worse rather than better. ACQ and similar copper-based preservatives run roughly three times more corrosive to galvanized steel than the old CCA they replaced, which is why the residential standard moved up to G185.

Simpson Strong-Tie states the pairing rule directly: with ZMAX or hot-dip galvanized connectors, use fasteners galvanized to ASTM A153 or specifically approved for ZMAX and HDG; with stainless connectors, use stainless fasteners. Mixing them introduces galvanic corrosion, where two dissimilar metals in the presence of moisture drive metal loss at the joint — exactly where you cannot see it.

The code backs this up: for preservative-treated wood, the IBC and IRC require fasteners that are hot-dip galvanized, stainless steel, silicon bronze or copper. Electroplated fasteners do not qualify.

Why Hanger Nails Are Short and Angled

A 1-1/2" hanger nail looks too short to be structural, and that is the most common reason people substitute something longer. The length is deliberate.

Many face-mount hangers — Simpson’s LUS series among them — use double-shear nailing. The joist nails are driven at an angle through the hanger, through the joist, and into the header beyond it. Each nail therefore crosses two shear planes instead of one, distributing the load through two points rather than one.

Two consequences follow. The connection reaches its rated capacity with fewer nails, and the nails do not need to be long, because the geometry rather than the embedment is doing the work. Driving a longer fastener straight in instead defeats the design: one shear plane, less capacity, and a connection that no longer matches the tested assembly the hanger is listed under.

SD Is Not the Only Screw — Check the Hanger

“Use Simpson SD screws” is the usual shorthand, and for most light face-mount hangers it is correct. It is not universal.

The rule that actually governs: whatever the manufacturer’s catalogue lists for that specific model is what earns the published load. Simpson’s own guidance is that if you specify the type and number of fasteners and install them as shown, you get full design values — and that many connectors accept either nails or SD screws, while some must use SDS. Substituting up is still substituting.

Pro Tips

Where installers lose capacity on a connection that looks finished.

Common Mistakes

Where to Buy

Both options below are the correct part for a standard face-mount hanger. The nails are the code default and the cheaper of the two; the SD screws cost more but install without a nail gun and without hammering in a tight bay.

As an Amazon Associate, BuildToolHQ earns from qualifying purchases.

Frequently Asked Questions

Can I use screws instead of nails in joist hangers?

Yes but only specific connector screws listed in the hanger manufacturer ESR report - typically Simpson Strong-Drive SD screws. Standard deck screws, drywall screws, and wood screws are NOT code compliant in joist hangers. They lack the shear strength rating required for structural connectors. Using non-rated fasteners voids the load rating of the hanger.

Why can I not use drywall screws in joist hangers?

Drywall screws are hardened and brittle to drive through gypsum cleanly. They have poor shear strength and snap under lateral load. Joist hangers are loaded primarily in shear - the fastener resists the joist being pulled downward. A drywall screw in a joist hanger can fail at a fraction of the rated capacity under normal floor loads.

What nails do I use for Simpson Strong-Tie joist hangers?

Most Simpson face-mount hangers require 10d common nails (0.148 inch diameter x 1-1/2 inch long). The specific nail size is listed in the product installation instructions and the ICC-ES ESR report for each hanger model. Never substitute a different nail size or type - the load rating is calculated for the specified fastener.

Are Simpson SD screws better than nails for joist hangers?

Simpson SD screws typically provide equal or higher load values than 10d nails in the same hanger and are preferred where a nail gun is not available. They are also easier to install in tight spaces and easier to remove if adjustment is needed. Use the 1-1/2 inch SD screw where 10d nails are specified.

What happens if I use the wrong fasteners in joist hangers?

Using non-rated fasteners in joist hangers voids the engineered load rating of the connector. The connection may appear sound visually but carry significantly less load than rated. This is a structural deficiency that building inspectors will flag and that can lead to floor failure under normal occupancy loads. Always use manufacturer-specified fasteners.

Related Guides

• Joist Hangers vs Toenailing — When to use each
• Structural Screws vs Lag Bolts — For framing connections
• Deck Ledger Attachment — How to anchor your ledger board
• AI Foreman — Complete project planning for deck and framing work
• Nail Size Chart: Penny Sizing Explained — Common vs sinker vs box nail diameters, and the real IRC requirements