Buying cedar deck boards should be simple, but the lumberyard throws a lot at you. Five-quarter or two-by. Square edge or grooved. Clear or knotty. Kiln dried or green. Pick wrong and you either overpay or end up with boards that fight your design.
This guide is about deck boards specifically. You will learn which sizes and profiles work best underfoot, how to read decking grades, how many boards your deck actually needs, and where to buy cedar for the best mix of price and quality.
Start Here: What Makes a Good Cedar Deck Board
Cedar earns its spot on decks because it resists rot and insects on its own, stays flat, and feels warm and forgiving underfoot. Unlike a hardwood, it is soft enough to cut and fasten easily. Unlike pressure-treated pine, it does not need chemicals to survive outdoors.
For a deck surface, three decisions matter most: the board size, the edge profile, and the grade. Get those three right and everything else falls into place.
Cedar Deck Board Sizes and Profiles
Deck boards come in a narrower set of options than general cedar lumber, because the board has to walk well and span your joists. Here is what actually gets used.
5/4 x 6 Cedar Decking: The Standard
If you buy cedar decking, you will most likely buy 5/4 x 6. Said out loud it is five-quarter by six. The board is nominally 5/4 thick but actually measures a full one inch by five and a half inches. It is the sweet spot: strong enough for standard 16-inch joist spacing, light enough to handle easily, and cheaper than a thicker board. Stores stock it in lengths from about 6 feet up to 20 feet.
2 x 6 Cedar Decking: The Heavier Option
A 2 x 6 board actually measures an inch and a half by five and a half inches. That extra half inch of thickness makes it stiffer, so it spans farther between joists, resists bounce, and holds up well as a stair tread. It costs more and weighs more, so most homeowners use it only where the extra strength earns its keep.
Edge Profiles: Square, Radius, Grooved, and Tongue and Groove
The edge of the board shapes both the look and the install method.
- Square edge. Flat sides with screws driven through the face. The simplest and cheapest, though the screw heads show.
- Radius edge. Slightly rounded corners that feel gentler on bare feet and shed water. This is what most big-box stores stock.
- Grooved edge. Slots milled into both sides so hidden fasteners clip in from below. You get a clean, screw-free surface, but the boards and clips cost more.
- Tongue and groove. Boards lock together with no gaps. Use it only on covered porches, since without gaps water has nowhere to drain.
Which Cedar Species for Deck Boards?
Cedar is a family, not a single wood, and only a couple of species make good decking. Western red cedar deck boards are the default choice across most of the country, prized for warm reddish tones, natural stability, and strong decay resistance. Western cedar deck boards from Canada and the Pacific Northwest are what most yards mean when they simply say cedar decking.
Alaskan yellow cedar is harder and even more durable, a premium pick if the budget allows. Northern white cedar costs less and works, though it is softer and more prone to cracking. Eastern red cedar is aromatic and dense but knotty and harder to stain, so it lands more often in posts and closets than in a smooth deck surface. In short, for most decks, western red cedar is the answer.
Understanding Cedar Decking Grades
Grade decides how many knots you live with and how much you pay. For decking, the practical choice comes down to two families.
| Decking grade | What it looks like | Who it suits |
|---|---|---|
| Architect Clear | Virtually knot-free, straight grain, flawless face | Formal, high-end decks, usually special order |
| Custom Clear / C and Better | Clear wood with only small, minor characteristics | Premium look at a friendlier price |
| Select Tight Knot (STK) | Sound, tight knots on a smooth, skip-free face | Most cedar decks, rustic charm and value |
| Standard or economy knotty | More and larger knots, some rough spots | Budget builds and low-visibility areas |
Most homeowners buy Select Tight Knot, often labeled STK, and are happy with it. That is the grade stacked at the big-box stores. Step up to a clear grade only if you want a smooth, uniform surface with no knots at all.
Two more labels worth checking on the tag. Kiln dried means the boards were dried and are stable and ready to finish. Green, or unseasoned, boards still hold moisture and will shrink as they dry, which changes how you space them. And boards with more heartwood, the darker wood from the tree’s center, resist rot better than pale sapwood.
How Many Cedar Deck Boards Do You Need?
Cedar decking is usually sold by the linear foot or by the board, not by the square foot, so you need a quick conversion. Here is the simple version for standard 5/4 x 6 boards, which cover five and a half inches of width each.
- Find your square footage. Multiply deck length by width. A 12 by 16 foot deck is 192 square feet.
- Convert to linear feet. Multiply square footage by about 2.1 for boards that are five and a half inches wide. That 192 square foot deck needs roughly 400 linear feet of decking.
- Divide by board length. Using 16-foot boards, 400 divided by 16 is 25 boards.
- Add waste. Tack on 10 percent for straightforward rectangles, and 15 percent if your deck has angles, picture framing, or a diagonal layout.
A tip from the field: buy the longest boards that fit your deck run. Fewer butt joints means a cleaner look and fewer weak points where water can collect.
Where to Buy Cedar Deck Boards
You have four real options, and the right one depends on the size and finish level of your project.
Big-box stores like Home Depot, Lowe’s, and Menards are the easiest place to start. They carry 5/4 x 6 red cedar decking, usually kiln dried with a radius edge, in a range of lengths. Selection skews to knotty STK grade, and stock varies by store and season.
Local lumberyards typically beat the big-box stores on grade selection and staff knowledge. Specialty cedar mills and suppliers open up the full catalog, including grooved profiles, custom lengths, clear architectural grades, and factory prefinished boards. Prefinishing seals all four sides and costs about half of staining on site, which is worth pricing out.
The fourth option is to let your builder source it. A contractor buys at trade pricing, orders the right quantity with the right waste factor, and knows which local yards carry good stock. If you would rather skip the sourcing entirely, find a deck builder naperville il homeowners trust to handle the material order and the build together.
Before You Buy: A Quick Checklist
- Inspect the stack. Sight down each board for cup, crook, and twist. Cedar is stable, but every stack has a few culls.
- Check the moisture. Kiln-dried boards are ready to install and finish. Green boards need to acclimate and will shrink.
- Buy stainless fasteners. Cedar’s natural oils react with plain steel and leave black stains. Stainless screws are the right call, and they cost less than fixing streaks later.
- Match the boards to your joists. 5/4 decking wants joists 16 inches on center. Wider spacing or a diagonal layout calls for 2x boards or tighter joists.
- Order extra. Ten to fifteen percent of waste is normal, and returning a few boards beats a second trip mid-project.
Frequently Asked Questions
What size are cedar deck boards?
The standard cedar deck board is 5/4 x 6, which actually measures one inch thick by five and a half inches wide. Lengths run from about 6 to 20 feet. A thicker 2 x 6 option measures an inch and a half by five and a half inches and spans farther.
What is the best cedar for deck boards?
Western red cedar is the best all-around choice for deck boards, offering warm color, natural rot resistance, and excellent stability. Alaskan yellow cedar is a harder, premium alternative. Northern white cedar costs less but is softer.
What grade of cedar decking should I buy?
Most homeowners choose Select Tight Knot, or STK, which has sound, tight knots on a smooth face and offers the best value. Choose a clear grade like Custom Clear or Architect Clear if you want a knot-free, formal surface.
Where can I buy cedar deck boards?
Home Depot, Lowe’s, and Menards stock common 5/4 x 6 cedar decking. Local lumberyards offer better grade selection, and specialty cedar mills carry custom profiles and clear grades. Your deck builder can also source boards at trade pricing.
How many cedar deck boards do I need?
Multiply your deck’s square footage by about 2.1 to get linear feet for 5/4 x 6 boards, then divide by the board length you plan to buy. Add 10 to 15 percent for waste, more if the deck has angles or a diagonal pattern.
The Bottom Line
Buying cedar deck boards comes down to three calls. Pick 5/4 x 6 unless you need the strength of a 2x. Choose Select Tight Knot for value or a clear grade for a flawless surface. And match the edge profile to the look you want, with grooved boards and hidden fasteners for the cleanest finish.
Buy from a source that carries real grade options, order 10 to 15 percent extra, and use stainless fasteners. If you would rather have it handled start to finish, ask find a deck contractor in barrington for your next project for a free estimate on materials and installation.