Whether you are building a deck or resurfacing an existing one, it is important to choose a strong enough board to suit your joist spacing. The 2×6 and 5/4 decking boards are the most popular names so let’s see how they compare.
The 5/4 lumber is a high-quality deck board with a deluxe appearance making it suitable for surface decking where people can sit, relax, or walk.
The 2×6, on the other hand, is multipurpose lumber that can be used for floors, walls, roof framing, and as deck boards. It can also be used as deck joists and railings.
When compared to the 5/4 board, the 2×6 board is 1/2 inch thicker than the 5/4 board and will provide more sturdiness. However, this comes at a price higher than the 5/4, which is of good quality and appearance. Both deck boards are of the same material and will last as long as they are well taken care of.
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The table below provides a more in-depth comparison between the 2×6 and 5/4 decking.
| 2×6 Decking | 5/4 Decking | |
| Material | Treated spruce, pine, and fir. | Treated spruce, pine, and fir. |
| Thickness | 1-1/2 inch (38mm) | 1 inch (25mm) |
| Joist spanning | Spans 24 inches (600mm) when perpendicular to the joist and 16 inches when it is diagonal to the joist. | Spans 16 inches when laid perpendicular to the joist and 12 inches when it is diagonal to the joist. |
| Weight | 2.36 pounds per linear foot. | 1.59 pounds per linear foot. |
| Shape | Flat top and bottom with square-cut edges. | Flat top and bottom with rounded edges. |
| Appearance | Not so pretty but has a solid and more robust look with square edges. | Beautiful appearance with good shadowing produced by rounded edges. |
| Cost | From $1.62 to $2.44 | From $1.15 to $152 |
Differences between 2×6 and 5/4 Decking
There are lots of differences between the 2×6 and 5/4 decking, which can be seen in their thickness, span, weight, appearance, and cost.
Thickness
The thickness of the board is an important factor to consider when building a deck because it affects the spanning of the joist and the height of the support structure.
At 1-1/2 inch thickness, the 2×6 board is half-inch thicker than the 5/4 board. This extra inch increases the distance it can span to 24 inches. While the 5/4 board provides two-thirds of the 2×6 board, it has a spanning distance of 16 inches. Also, the thickness affects how long it takes for the board to dry and whether it will cup or twist. The thicker board takes more time to dry than the thinner board, and it does not easily cup or twist.
Span
The space between the joists is another important factor to consider because it determines the size of joists and beams to be used and the thickness of the deck board to be used on the surface. The standard spacing between joists is 12, 16, and 24 inches on-center (O.C.) apart. If laid perpendicular to the joists, the 2×6 board can span up to 24 inches and 16 inches when it is placed diagonally. While the 5/4 spans up to 16 and 12 inches for perpendicular and diagonal placement, respectively.
Practically if a 12-inch wide deck requires 10 joists, using a 5/4 deck board that spans up to 16 inches, it will take only 7 joists for a deck of the same width using a 2×6 deck board that spans up to 24 inches. This means the more the spanning distance, the lesser the joist, and thus lesser cost.
Weight
If you are a homeowner DIYing your decking, you might want to consider the weight of the boards to use. Moisture content, dimensions, wood specie, and treatment are all factors that affect the weight of boards. A 2×6 pressure-treated SPF deck board weighs about 2.36 pounds per linear foot, while a 5/4 deck board of the same material weighs 1.59 pounds. With this, you already know which option will be the easiest to carry all by yourself.
Appearance
The appearance of your decking will take the profile of the deck board used. The same wood’s 5/4 and 2×6 deck boards will look similar in color and texture, but few differences can be spot on around the edges, flawless finish, and thickness. The 2×6 has a squared edge and a bulky look, while the 5/4 is thinner, with better finishing and a rounded edge that provides more shadowing. The 5/4 board, because of its beautiful appearance, is mostly preferred for finishing deck surfaces.
Cost
The 2×6 and the 5/4 decking are both affordable options. However, one is more budget-friendly than the other. Giving a specific cost for each decking might be farfetched as other factors like location, wood mill, type of wood treatment, availability, and season affect the cost of each decking. Despite this, the 5/4 is almost always the cheaper option than the 2×6 decking. Their prices might vary, ranging from $1.62 to $2.44 for a 2×6 board per linear foot and $1.15 to $152 for a 5/4 board per linear foot.
When discussing the cost, there is also a question of resell value and whether it matches the cost. This depends on personal preferences. A buyer that wants an alluring decking will be willing to splash the cash on a 5/4 decking. In contrast, a buyer that prefers sturdiness will go for the 2×6 decking. Both decking are in demand, so finding a buyer won’t be a hassle.
Conclusion
The 2×6 and 5/4 will both make a quality deck. They are easy to maintain and require annual sealing to prolong the life of the deck. They have the same width, so they will cover the same area and use the same number of fasteners. Choosing between both decking boils down to personal preference. The 2×6 deck is known for strength, especially if it is spanned at 16 inches. So it is suitable for decks that are built to carry heavy loads. The 5/4 decking, on the other hand, is a more affordable option with good quality and a better appearance specifically made for surface decking.
