Pro Guide on Using 304, 305, and 316 Stainless Steel Wood Screws

You could look at 304, 305, and 316 stainless steel wood screws side by side and they'd look exactly the same. They're all labeled stainless steel. But when you're building near the ocean, use PT lumber, or fastening tannin-rich wood boards, they perform completely differently.

This guide is based on 28 years of building decks and fences. You have three main factors to consider when deciding between 304, 305, and 316:

1. Your location (how close you are to salt water)
2. The wood type you're building with (PT, hardwoods, etc.)
3. Whether your fasteners will be visible or hidden

As you read through this expert guide, you'll see how each of these factors plays into your decision. By the end, you'll have a complete picture of which grade works for your specific project.

304 vs 305 vs 316: Which Is Better For Your Build?

• If you're building WITHIN 3 miles of an ocean, bay, sound, or gulf, use 316
• If you're using pressure-treated lumber AND within 3 miles of coast, use 316
• If you're using pressure-treated lumber AND inland (10+ miles from water), use 304 or 305
• If you're building with cedar or redwood AND fasteners are visible, use 305 minimum; 316 preferred
• If you're building with tropical hardwoods (Ipe, Cumaru), use 304 or 305 (but pre-drill; it's mandatory)
• If you're building a commercial structure or dock, use 316 (even if inland)
• If you're inland 10+ miles from water and NOT using cedar/redwood, use 304
• If you're unsure about your distance to water, use 305 (the safe middle choice)

Why Grade Matters: 304 vs 305 vs 316 Grades Explained

304 Stainless Steel Wood Screws

What 304 SS is Made Of: 18-20% chromium, 8-12% nickel, NO molybdenum

How 304 Resists Corrosion: Forms a self-healing chromium oxide protective layer when exposed to oxygen

Where Should You Use 304:

• Inland projects (10+ miles from saltwater)
• Pressure-treated lumber in non-coastal areas
• Most non-coastal residential applications

Where Should You NOT Use 304: Chloride ions from salt water punch right through the chromium oxide layer, causing pitting corrosion. You'll see tea stains if you're coastal.

So, what are “tea stains”?

Tea stains are those light brown or bronze discolorations that look like brewed tea on your screws. They're not actually rust (like what you see on coated screws), just a cosmetic surface issue that won't hurt your fasteners.

They show up when you're using the wrong stainless steel grade (like 304) in tough coastal or poolside environments where chlorides break down the protective chromium oxide layer. You can wipe them right off with a baking soda paste or a quick vinegar soak, and your screws stay solid and ready to go. 

305 Stainless Steel Wood Screws

What 305 SS Is Made Of: 17-19% chromium, 11-13% nickel (higher than 304), NO molybdenum

How 305 SS Is Different Than 304: That extra nickel improves two critical things:

1. Better corrosion resistance — Stands up better to moisture and certain environments
2. Tannin resistance — Won't stain as easily when cedar or redwood tannins attack

When We Use 305:

• Cedar and redwood decks (any location)
• Areas 3-10 miles from coast
• Anywhere you want better protection than 304 but don't need 316's premium price
• High-humidity inland areas (Minnesota, Georgia, Tennessee)

Why We Use 305: It's our versatile choice for most projects outside the immediate coastal zone. We've ripped apart 30-year-old decks we built with 305 stainless screws, the fasteners still look new. Zero corrosion, no structural issues. That's data you can count on.

The Cedar/Redwood Problem It Solves: Cedar and redwood contain tannins—natural acids that create beautiful wood but wreak havoc on fasteners. These tannins react with iron to create blue-black stains visible within days. With 305's higher nickel content, staining happens much more slowly (years instead of months, or doesn't happen at all).

What We Know: The same tannins and oils that protect cedar and make it so desirable wreak havoc on coated screws. We've learned that those oils gradually eat away at coatings, eventually exposing the structural metal underneath. That's when corrosion starts. With 305, we eliminate that risk.

316 Stainless Steel Wood Screws

What 316 SS Is Made Of: 16-18% chromium, 10-12% nickel, 2-3% molybdenum

What Makes 316 Different Than 304 and 305: Molybdenum. It's not just another element—it actively blocks chloride ions from penetrating the chromium oxide layer. That's the difference between "resistant" and "protected."

When We Use 316:

• Within 3-5 miles of salt water (coast, bay, gulf)
• Docks, jetties, boardwalks, marinas
• Commercial structures or municipal decks (liability and longevity expectations mean building for 30-40 year lifespan)
• Pressure-treated lumber in coastal areas
• Pool decks (chlorine attacks other grades rapidly)

When To Use 304 vs 305 vs 316 Based On Your Location

Coastal Areas (Within 3 Miles of Salt Water)

Florida (Atlantic & Gulf Coasts)

Environment: Salt spray 24/7, high humidity, warm year-round

Fastener Choice: 316 stainless steel ONLY

The builders we work with in Jacksonville and Miami don't consider 304 at all. We've learned this lesson through experience: spending more on fasteners saves customer relationships and repeat business. The cost of rebuilding sections or dealing with warranty claims far exceeds the fastener premium.

California Coastal (San Francisco Bay, Southern California)

Environment: Salt fog, cool temperatures, moderate humidity

Fastener Choice: 316 within 3 miles; 305 acceptable 3-10 miles inland

Even though the fog seems less aggressive than Atlantic spray and cooler temperatures slow corrosion, don't underestimate it. Properties just 3 miles from the ocean experience enough salt accumulation to require 316 if fasteners are visible.

We treat these areas with the same standard as Florida, just with the flexibility of 305 a little further inland.

North Carolina/Atlantic Seaboard

Environment: Seasonal salt spray, humid summers, moderate winters

Fastener Choice: 316 within 3-5 miles; 305 acceptable 5+ miles inland

Less year-round salt exposure than Florida, but summer humidity is high. The closer to water, the higher the grade.

Australia/New Zealand (Coastal)

Environment: Intense salt spray, high UV, year-round moisture

Fastener Choice: 316 mandatory within 5 kilometers of coast

Within 5km of coast, 316 is the choice, particularly if fasteners are visible, since 316 is far less likely to show "tea-staining" (brown discoloration from salt residue)

Inland Areas (10+ Miles from Coast)

Colorado/Mountain West (Denver, Boulder)

Environment: Dry high altitude, 40-60 freeze-thaw cycles per year, intense UV

Fastener Choice: 304 acceptable; 305 preferred if using cedar/redwood

The common misconception is that freeze-thaw requires premium fasteners. Actually, no. No salt—that's the main driver. The freeze-thaw issue? That's NOT about fastener grade.

Here's what actually happens: We have to account for seasonal freeze-thaw movement—thus the term "floating deck." We design for seasonal wood movement, not fastener expansion. The key is pre-drilling, adequate embedment, and 2-3 screws per joist minimum.

Minneapolis/Minnesota/Great Lakes Region

Environment: Severe freeze-thaw, high humidity in summer, acidic rain

Fastener Choice: 304 for standard decks; 305 if using cedar or natural finishes

Same as Colorado—the grade matters less than installation design. The real problem we see: seasonal wood movement causes fastener withdrawal, especially with pressure-treated lumber in the first year. That's a design issue, not a material issue.

Texas Inland (Austin, Dallas)

Environment: Hot dry summers, minimal freeze-thaw, sporadic high humidity

Fastener Choice: 304 for standard PT lumber; 305 for cedar decks

Why: No freeze-thaw risk; tannin staining and humidity are main concerns. When we build cedar decks here with visible fasteners, we upgrade to 305 without hesitation.

What SS Grade to Use With What Wood

Pressure-Treated (PT) Lumber

Modern PT lumber (ACQ/CA treated) contains copper-based preservatives that create galvanic couples with fasteners. When moisture is present, copper ions leach out and attack fasteners. We've learned this the hard way over 28 years.

What Works:

• NEVER use galvanized with ACQ/CA treated wood (zinc fails 3-5 years)
• NEVER use regular coated fasteners (copper eats the coating)
• USE stainless steel (any grade; 304 minimum acceptable)

Over the years, we've watched builders use gray polymer coated screws with pressure-treated lumber expecting them to last. They don't. The chemicals in treated lumber eat up anything that's not hot-dipped galvanized or stainless steel. We make sure all our crews understand this before they buy a single fastener.

By Location with PT Lumber (Our Standard):

• Inland non-coastal: 304 acceptable (10+ years life)
• Inland 3-10 miles from coast: 305 preferred
• Coastal within 3 miles: 316 required

Important Tip: Match all fastener types. Don't use 304 screws with galvanized hangers (creates electrochemical failure). Use all 316, OR all 304, OR all galvanized—never mix.

Cedar & Redwood

The Tannin Problem We Deal With: Cedar and redwood contain natural acids (tannins) that create blue-black staining when they react with iron. This staining is permanent without removal and appears within days/weeks.

The same tannins and oils that protect the wood and make it beautiful wreak havoc on fastener coatings. We've learned that those oils gradually eat away at coatings, eventually exposing the structural metal. That's when real corrosion starts.

Our Fastener Specifications:

• Visible fasteners: Use 305 minimum; 316 preferred
• Hidden fasteners: 304 acceptable
• Why: Higher nickel content in 305/316 prevents direct iron reaction with tannins

Tropical Hardwoods (Ipe, Cumaru, Teak, Merbau)

These woods are 3-4 times harder than cedar. If you try to drive stainless screws without pre-drilling, they'll snap.

Stainless doesn't drive into hard tropical wood the way it does into softwood. It's like going into very hard, dense wood and it just strips out. We've learned to pre-drill without exception. For Ipe, we sometimes joke that we go through drill bits like we're using a vise, but it's serious business.

Our Non-Negotiable Process:

1. Pre-drill pilot hole at 90% of screw diameter
2. Use carbide drill bits (regular bits break)
3. Apply wax or lubricant to screw threads
4. Use lower RPM to prevent heat buildup
5. Consider larger-diameter screws (less prone to snapping)

Grade Choice: 304 or 305 is fine (corrosion risk low in naturally durable woods). Pre-drilling matters infinitely more than grade.

The True Cost: Why 316 Often Saves Money

DIYers and some contractors look at upfront price and choose 304 to save money.

Real Numbers (Eagle Claw Stainless Steel Deck Screws)

• Eagle Claw 304 Stainless Steel Deck Screws (#10 x 3" - Per 350 Pack): $83.99
• Eagle Claw 316 Stainless Steel Deck Screws (#10 x 3" - Per 350 Pack): $102.99

Difference: $19 per 350-screw pack. That's about 5-6 cents per fastener.

For a Typical Residential Deck (800-1000 Fasteners)

Using #10 x 3" screws, you'd typically need three 350-packs:

Option 1: 304 Stainless Steel (Inland Non-Coastal)

• 3 packs × $83.99 = $251.97
• Total: $252

Option 2: 316 Stainless Steel (Coastal/Premium)

• 3 packs × $102.99 = $308.97
• Total: $309

The Difference: Just $57

That's less than a fancy dinner out. And your deck gets protection that actually pays for itself over time. As a percentage of total deck cost ($3,000-6,000): About 1-1.5%.

For ledger bolts and structural connections (where we use Simpson Strong-Drive® products), the premium is more significant because those are specialty items. But again, we're talking about $100-200 more for an entire commercial deck project.

The Real Math: Cost Per Year of Use

Here's where the penny-pinching mentality breaks down.

If your deck lasts 15 years with 304 vs 30 years with 316:

304 Cost per year: $252 ÷ 15 = $16.80 per year
316 Cost per year: $309 ÷ 30 = $10.30 per year

316 is actually cheaper per year of use.

Plus you avoid:

• Replacement labor ($1,500-3,000 if deck fails early)
• Rebuilding sections or entire deck
• Years of dealing with the problem
• Customer disappointment and negative reviews

What We Tell Clients

We're not just buying fasteners for $57 more. We're buying peace of mind. We're buying a structure that doesn't fail in 5 years. We're buying the ability to never hear from that client again because the deck is still solid 20 years later. That's worth the $69 difference—every single time.

One thing coastal builders understand that inland builders sometimes miss: the real cost of cutting corners shows up years later. We've spent tens of thousands fixing decks where the fastener choice cost just $50-100 to get right the first time.

304 vs 305 vs 316: Making the Right Choice for Your Project

With 28 years of building wooden structures—from residential decks and fences to commercial docks and boardwalks—we've learned that fastener selection is one of the highest-impact, lowest-cost decisions in any outdoor project. We've seen what works and what fails. We've fixed the mistakes.

Don't guess on something this important. Ask us about the right screws for your specific deck, fence, pergola, or dock project. We'll assess your location, wood type, and structure—just like we do on every job we build.

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