How Thick Are Deck Boards? 1×6 vs. 5/4×6 Hardwood Decking?

Most Ipe Decking is sold in two common thicknesses: 1×6 and 5/4×6. A nominal 1×6 deck board is actually 3/4″ thick, while a 5/4×6 deck board is actually 1″ thick. For most residential projects, 1×6 Ipe is the trusted, go-to profile and is used in more than 90% of the hardwood decks we supply. The thicker 5/4×6 profile is generally reserved for commercial builds, heavy-traffic applications, or framing with wider joist spacing.

After decades of supplying both options, we’ve found that 1×6 usually delivers the best balance of strength, easier installation, and lower overall cost and waste for homeowners and contractors. If you’re still getting familiar with the material itself, start with our Ipe Decking resource page.

Below, I’ll explain how thick deck boards actually are, why 1×6 is usually the smarter choice, and when 5/4×6 may be a meaningful upgrade.

Comparison of 1x6 and 5/4x6 Ipe decking board thicknesses showing installation, cost, and performance differences for Brazilian hardwood deck construction.

Let’s get the common misconceptions out of the way, first.

Using 5/4×6 decking WILL NOT:

make them last longer

make your deck stronger in any meaningful way

prevent boards from warping (find out what will)

feel different when you walk on them

make your wife and children love you more

Using 5/4×6 decking WILL:

be more expensive than 1×6

be harder to straighten, install, handle and ship

be more likely to drive you crazy by breaking screws during installation

I’m a big fan of “over-building” projects- when it’s done in the right place. Strength and longevity come from optimizations in the framing, like reducing joist spacing from 16 inches to 12 inches, not from using thicker deck boards. Moving to 5/4 material doesn’t significantly improve durability or performance. It mainly adds weight, cost, and installation difficulty, and it is not an effective solution for cupping, despite what other resources suggest.

– Sam

📏 Deck Board Thickness: Actual vs. Nominal Dimensions

Nominal sizes:

1×6 Decking: ¾″ thick (actual 0.75″ × 5.5″)
5/4×6 Decking: 1″ thick (actual 1.0″ × 5.5″)

According to engineering standards, both 1×6 and 5/4×6 Ipe decking are rated for a 100 lb/sf live load, but with different joist spans:

Nominal Size	1×4 (.75″ x 3.5″)	1×6 (.75″ x 5.5″)	5/4×4 (1″ x 3.5″)	5/4×6 (1″ x 5.5″)	2×4 (1.5″ x 3.5″)	2×6 (1.5″ x 5.5″)
Joist Span @ 100 psf	24″	24″	32″	32″	36″	48″

That means a 1×6 board can easily handle standard 16″ joist spacing, with capacity to spare.

So, unless you’re building a heavy-duty commercial boardwalk or spanning beyond 24″, 5/4×6 simply adds cost, weight, and installation hassle — without structural benefit.

💡 The Smart Value of 1×6 Decking

At Brazilian Wood Depot, we recommend 1×6 Ipe for almost every deck project. Here’s why:

Lighter, easier to handle: 1×6 boards weigh less and are easier to cut, fasten, and install.
Lower material cost: You’ll save 15–25% on lumber without sacrificing strength.
Proven performance: 1×6 Ipe decking has been successfully installed in over 10,000+ BWD decks nationwide with no structural compromises.
Meets standard code requirements: 24″ span rating exceeds the 16″ on-center requirement for most residential decks.
Smarter long-term investment: Fewer joists, less labor, and no wasted material thickness where it’s not needed.

Learn more about installation guidelines and spacing in our Decking Installation Guide.

How Thick Should Deck Boards Be?

For most residential hardwood decks, 3/4″-thick 1×6 Ipe Decking is the better choice. Installed over standard 16″ on-center framing, our 1×6 Ipe Decking provides more than enough strength for typical residential use without the added weight, cost, and installation difficulty of a thicker board.

Moving up to 5/4×6 Ipe Decking gives you a full 1″-thick board, but thicker does not automatically mean a better-performing deck. If the goal is simply to build a stiffer, more substantial structure, we generally prefer improving the framing — such as reducing joist spacing — rather than adding unnecessary thickness to every deck board.

When does 5/4×6 make sense? Wider joist spacing, heavy-traffic or commercial applications, certain replacement projects, and situations where the heavier 1″ profile is specifically desired can all justify the upgrade. For the overwhelming majority of residential decks, however, 1×6 Ipe delivers the strength you need with less weight, easier installation, and better overall value.

🪵 When to Choose 5/4×6 Decking

There are a few cases where 5/4×6 might be a better fit:

Longer Spans: For decks with joist spacing over 24″ — common in docks, boardwalks, and large commercial builds — the added thickness ensures stability. Learn more about deck span ratings at International Code Council.
Commercial Traffic: Municipal projects, Boardwalks, Beach Crossovers; these projects undergo substantial wear and tear from the elements and foot-traffic. These are reasonable (but still not necessary) reasons to consider the thicker board.
Installation Pre-Conditions: For instance, if 1″ thick decking boards needs to be replaced but the siding or flashing on the home meets up nicely with that area- it MIGHT be a reasonable to consider using the thicker material. Even in these cases, there are often better ways to accommodate for this difference in thickness.
Aesthetic Preference: Some customers prefer the slightly more substantial profile of 5/4×6 ESPECIALLY when it comes to stair treads or handrails- areas where you’ll actually see the thickness difference.

Otherwise, the 1×6 profile delivers better value, easier handling, and cleaner installation.

🌎 Strength, Beauty, and Sustainability in Every Board

Both 1×6 and 5/4×6 decking from Brazilian Wood Depot are 100% RealWood™ — sustainably harvested and kiln-dried for optimal stability.

Ipe’s natural advantages include:

Janka Hardness: 3,490 lbf — harder than concrete
Longevity: 40–75 years with minimal maintenance
Fire Rating: Class A (same as steel or concrete)
Resistance: Unmatched durability against rot, termites, and decay
Natural Beauty: Deep chocolate to olive tones with striking cathedral grain

Every Ipe deck is a natural work of art — no two boards look the same. You can explore real-world installations in our Ipe Decking Gallery.

The Composite Comparison

You might be wondering how all this compares to composite decking.

Here’s a quick look:

Feature	Ipe Decking	Composite Decking
Lifespan	40–75 years	8–15 years
Fire Rating	Class A	Class C
Maintenance	Optional oil	Fades, cannot be restored
Appearance	Natural, unique	Uniform, artificial
Cost Over Time	Lowest (1 install)	High (replacement every 10 yrs)

Composite decking needs tighter 16″ spacing and still can’t match the strength, lifespan, or beauty of real hardwood.

Explore the full Ipe vs Composite Comparison for detailed data.

🧰 Installation & Maintenance Tips

Whether you choose 1×6 or 5/4×6, proper installation ensures your deck performs beautifully for decades:

Pre-drill every hole. Ipe’s density requires pre-drilling for clean screw seating.
Use stainless steel fasteners. Hidden clips or Pro Plug Systems are ideal for a seamless surface.
Seal all cuts. Apply Anchorseal End Wax to prevent end-checking.
Oil the surface (optional). Maintain rich brown color with Messmer’s UV Plus Natural, or let it gracefully silver over time.

You can also enroll in our Ipe Certified Course — a free professional-grade program that covers installation, airflow, maintenance, and sustainability.

Ipe 1x6 hardwood decking boards installed on a residential deck with rich reddish-brown tones and a smooth, wet finish.

✅ Final Word: Smarter Build. Better Value. Use 1×6.

For most residential and light commercial applications, 1×6 hardwood decking is the optimal balance of strength, performance, and value.

It meets and exceeds building standards, reduces costs, simplifies installation, and — when built with Ipe — will outlast nearly every other decking material on the planet.

1×6 Ipe decking is proven. Efficient. Smart.
And after 20+ years and thousands of successful builds, we can confidently say:
👉 Smarter build. Better value. Use 1×6.