The Pros and Cons of Cedar Decking
If the natural look of wood is tops on your list, use cedar. The heartwood of the tree (the deeper colored red part, not the white sap part) is rot resistant. Cedar doesn’t readily absorb moisture— and, since moisture is what creates twisting and splitting, cedar decking tends to lie flat and straight. Most carpenters figure a lifespan of 15 to 20 years for cedar deck boards, but it can deteriorate faster when used for ground-level decks and for shaded decks that are slow to dry out.
To retain the color, you have to clean it and reseal it every year or two, and even then it’s a losing battle. I’ve never seen a 10-year-old cedar deck that still had that warm, rich look of new wood. Cedar is also soft; when used for stairs or for decks where furniture gets dragged around a lot, the edges in particular can get beat up. Finally, the cost of the cedar is moderate, more than pressure-treated but somewhat less than composite.
Cedar is graded similarly to other western woods but its use is generally more concerned with appearance than structural strength. Most cedar lumber will be stamped with species and graded. Some high quality grades may not be stamped to prevent the wood from being defaced. You may run into some cedar grades at lumberyards that you may be unfamiliar with. Less technical grades are more subjective and are usually related only to appearance. We refer to these as vernacular or colloquial graded wood. The same lumber grades can vary between mills and from batch to batch. The best policy is to personally examine the wood before you buy it unless you are familiar and trust a specific lumberyard.
Trim Boards Knotty Grades Unseasoned or Seasoned
Select Tight Knot Grade or Number 2 – This grade has very few defects and some sapwood. Any knots present are sound encased and tight. It is generally regarded as a high quality choice for Cedar.
Number 2- Has more knots and sapwood. Number 2 will be less expensive than Select. This will be the bare minimum grade you will want to use for use on a deck.
PRESSURE TREATED WOOD
The pros and cons of pressure-treated decking
If economy and longevity are your bag, go with pressure-treated wood. It’s stainable, hard enough to resist abuse, and many brands carry a lifetime (though limited) warranty. But beware, not all treated woods are created equal. The standard treated decking at my local lumberyard costs less than cedar. But inexpensive treated wood is often full of moisture and will shrink unevenly and twist when it dries. One homeowner told me, “Yeah, my treated deck may last forever—but it’s going to look BAD forever too.”
We suggest you buy “choice,” “premium” or “select” treated boards. At about 40 percent more per linear foot, you’ll pay more, but the boards have fewer knots and straighter grain. And, since many of the higher grade choices are kiln-dried both before and after pressure treatment, they have less tendency to warp.