Comparing 5/4 Decking With 2×6 Deck Boards, Pros and Cons


There are two common decking options for a budget conscience deck to choose from, 5/4 decking or 2×6 deck boards. Both decking options have their pros and cons. Which one should you use for your deck?

For those looking for a distinct wood decking look, 5/4 decking is a good choice at an economical price. For those looking for a more robust, bulkier looking decking, 2×6 decking is a good pick with a square profile.

Much more goes into choosing between 5/4 and 2×6 decking, but those are some of the most distinct differences. The profile, strength and look of the decking.

When discussing the pros and cons of each decking with homeowners, often, two groups emerge.  Homeowners looking to keep their deck cost down will select 5/4 decking. Those more concerned about strength will choose the tradition 2×6 decking.

But let’s make a little more in-depth comparison to know which decking is best for you and your deck. Not just which one is stronger and the lowest price.

 2×6 Deck Boards5/4 Decking
MaterialTreated SPFTreated SPF
Thickness1 ½” (38mm)1″ (25mm)
Joist Spanning24″ (600mm)16″ (400mm)
Weight2.36 lbs (1.07kg) lnft*1.59 lbs (0.72 kg) lnft*
Profile cutSquare CutRounded Radius Edge
Cost Per Lnft$1.62$1.15

*Thank you, Roofonline, for your helpful lumber weight chart. If you wish to see a fuller selection of lumber weights, click their name.

Before discussing the differences between 2×6 and 5/4 decking, let’s go over some similarities.

Similarities of 2×6 and 5/4 Decking

Both 2×6 and 5/4 deck boards are made from Spruce, Pine Fir (SPF), more commonly Pine, especially in the United States Northwest.

Both are treated to prevent fungi growth and limit rot. Extending the lumber life to as much as 40 years but more commonly 15-20 years. Regular sealing to avoid water damage and annual maintenance extends their life and use. With the option of a wide variety of stains available to change your deckingOpens in a new tab. and deck’s look.

One of the things I like about both 5/4 decking and 2×6 is how easy it is to work with. It can be cut with standard wood tools, cut to any size and machined as required. All why still maintaining its structural properties, something that can not be said about composite deckingOpens in a new tab..

Both 2×6 and 5/4 can be fastened with face screws or camo edge screws. Or nailed if you insist, but you will make me cry if you do. ScrewsOpens in a new tab. are just so much better for decking.

All while allowing decking overhang. Helping your deck last longer and look better for years to come.

Both requiring gapping to allow the rain to drain. Often 1/8″ to 3/16″ (3-5mm) when the boards are dried but usually installed tight when still wet from the factory.

In so many ways, they are the same things, treated wood decking.

But in other ways, they are two different decking options entirely.

Differences Between 2×6 and 5/4 Decking

2×6 Decking is Thicker Than 5/4

The most noticeable difference is thickness. 5/4″ decking is thinner than 2×6 boards. Both with a deceptively different material thickness.

2×6 Deck Boards actual Dimensions 1.5″ x5.5.”

5/4 Decking Actual Dimensions 1″ x 5.5.”

Both being smaller than their names claim. If you use 5/4 decking, you are getting two-thirds of the board of a 2×6. Like getting a Big Mac without the middle bun, still decking just less.

There are some trades off with this difference. Some are positive, and some are not.

2×6 Decking Require Fewer Joist Than 5/4

The extra material of 2×6 boards increases the distance it can span between joists. Where 5/4 decking requires a joist every 16″ (400mm), 2×6 can span 24″ (600mm).

A 12′ (3.6m) wide deck using 5/4 deck requires ten joists for 16″ on centre spacing. The same width deck using 2×6 decking, with the larger 24″ (600mm) spacing will only require seven joists.

A saving of three joists for a 12′ (3.6m) wide deck.

A savings of 30%, or roughly $100 for a 12′ (3.6m) square deck when using 2×6 instead of 5/4 decking.

5/4 Decking is Lighter than 2×6

I love 12′ decks as they are a nice size. It is big enough to set up a few chairs and possibly a table but small enough not to take up the whole yard. Therefore, I carry many 12′ (3.6m) deck boards from the front street to the backyard.

5/4 decking being lighter may not seem like much, but it adds up. A 12′ (3.6m) 2×6 is roughly 28 lbs. The same length of 5/4 decking is only 19 lbs. I can carry two 2×6 to the back but three 5/4.

5/4 Decking is More Environmentally Friendly Than 2×6

One of the advantages of 5/4 decking is fewer trees have to be harvested to make your deck. Quick math, if three trees must be sawn down to make enough 2×6 for a 12’x12′ deck. Using 5/4 will only take two. That’s one more tree, left to be used for something else.

If you and your neighbour use 5/4 decking, your other neighbour’s decking requires no more trees to be cut down. The savings from your two decks provides the decking for his.

On top of these savings. Is the fact that more of a log can be cut into 5/4 decking then a 2×6. It’s that square peg into a round hole. The smaller the planks, the closer to the edges of the log they can be cut. It may not be much, but it is a few extra decking boards from every tree.

5/4 Decking Has Rounded Edges

Appearance-wise, the rounded edges of 5/4 decking make the deck look better. The shadowing creating by the rounding of the material hides the inconsistencies in gapping between boards.

The rounded over 5/4 decking also reduces water being trapped on the decking. Not concerning cupping, that’s a fastener and installation issue. But with the edges rounded off, the rain runs off easier. Like a bowl, if the rim is shorter, it holds less water. The same with decking, rounded edges minimize the rim of the bowl, holding less water.

Rounded edges between deck boards also make cleaning between deck boards easier. With a slightly larger gap near the board’s top for the broom to scoop out dirt and leaves. Even with the same gapping as square 2×6 decking.

The rounded edges also reduce the number of edge slivers. It is often the edge of a deck board that cracks, creating slivers to snag your feet on. But with 5/4 decking, the edges are rounded of reducing the potential for splinters.

Interesting side note, almost all composite decking imitates 5/4 decking, not 2×6. Not sure if this is a chicken or egg thing. But the profile of composite decking, the higher end decking on the market, is 1″ thick with rounded edges. Thoughts to pounder.

5/4 Decking Costs Less than 2×6 Boards

Often the deciding factor between decking is the price. Lumber fluctuates in cost throughout the year, especially during deck construction season, but 5/4 decking is almost always cheaper than 2×6.

At the moment of writing, 5/4 costs about 70% of the cost of 2×6 decking. With everything else being equal, using 5/4 decking on a 12′ x12′ deck will save you over $150 on decking costs. If you include picture framing or angle decking, it will only increase in savings for 5/4 decking.

12’x12′ Decking Cost Comparison

MaterialBoard PriceCost of Decking
5/4×5.5”-12’ decking$13.79$359
2×6-12’$19.99$520

There is the argument of saving with fewer deck joists. As 2×6 decking can be installed with joists at 24″ (600mm) on centre spacing where the max for 5/4 decking is 16″ (400mm). Which on a 12′ square deck will save you three 2×8 joists saving roughly a hundred dollars. But that is still less than the saving using 5/4 decking. But with the loss of the extra sturdiness that the 2×6 decking provides when installed on 16″ (400mm) joists.

Quality of Lumber Used Between 5/4 and 2×6 Decking

Now this will vary by mills and which lift of lumber you are pulling your decking from. But as a general rule.

5/4 decking includes more core cut boards than 2×6 boards, which is the most unstable part of the tree. Twisting and curling as it dries. Requiring more care during installation to straighten the decking and pull it tight to the joists. With the added potential of deck board popping up or edges lifting from seasonal pressure. Along with confusing the debate of bark side up or down without a bark side, with just the tree’s core.

The increasing number of cores included is partly due to the use of sapling trees for 5/4 decking boards. With smaller dimensions, 5/4 decking can be cut from smaller trees than 2×6 boards. Allowing for quicker harvest, but unfortunately, the younger trees or more prone to rot also. Which may cause decking failure sooner than when older growth wood is used.

Conclusion of Comparing 2×6 and 5/4 Decking

Whichever you choose, 2×6 or 5/4 decking, they will both provide a quality deck. Both will require annual sealing to increase the years of enjoyment on your deck. 5/4 bringing its distinct radius edges at a lower cost. But 2×6 boards creating a flat rigid deck surface.

Enjoy your affordable outdoor living space.

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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