How to Choose Between Cedar, Pressure Treated Wood & Composite Decking

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When choosing decking, the three factors I consider first are appearance, durability and cost, and any other builder likely does the same. When building a standard deck — and not a high-end one using ipé, black locust or some other expensive hardwood — the main decking choices are naturally weather-resistant softwoods like redwood and cedar, pressure-treated softwoods, and composites. Other choices, such as PVC or aluminum, are in the mix, but these three are the ones builders and homeowners most commonly choose.

Redwood is probably the most popular decking material in Northern California, where I live and work, but in much of the country, builders use various varieties of cedar instead. Since redwood and cedar are equally weather-resistant and similar in appearance, it’s fair to consider them together as a single option, so references to cedar in this post automatically include redwood as a possible substitute.

The homeowner who will ultimately use the deck has two other questions to consider: Do you plan to stain or finish the deck, and do you plan to give the deck regular maintenance during its lifetime? Here, we’ll discuss the pros and cons of the three main decking choices.

Cost Comparison

Cost is often the first consideration when considering a large project like a deck, so let’s address that first.

• Despite being manufactured with recycled materials, composites are the most expensive choice. Cost varies with quality and brand and can range from $8 per square foot for a low-end product to $18 psf for a premium one.
• Weather-resistant softwood is a middle-of-the-road choice in terms of price. Standard 2X6 cedar decking boards cost between $4 and $8 psf.
• Pressure-treaded softwood (usually pine) is the most economical choice. It costs from $2 to $8 psf.

Pros and Cons of Composite Decking

The high cost of composite decking is partially offset by the maintenance requirements, or lack of them. Most composite products require little to no maintenance — no staining, sanding or resealing — and they resist color fading and generally outlast wood decking. That doesn’t necessarily mean you can’t stain them. A few products will accept a stain after a period of exposure to the sun (usually about six months).

Here are some other advantages:

• No warping: All composite boards delivered to your site will be straight, and they won’t curl or twist after installation.
• Hidden fasteners: Composite manufacturers provide systems for attaching the decking to joists with hidden fasteners, which makes for a cleaner-looking deck overall.
• Easy to clean: You can clean composite decking with a garden hose or a bucket of soap and water and a scrub brush. Power washing is not recommended.

Here are some of the problems associated with composite decking:

• Traps heat: Composite decking contains heat-absorbing plastic, which can make the deck uncomfortable for walking on a hot day.
• Susceptible to moisture: Although this issue has largely been addressed by manufacturers — especially Trex, which had to settle lawsuits over it — it’s still possible for composite fibers to absorb moisture through screw holes and other defects, leading to swelling and mold.
• Lacks structural strength: Composite decking is not as rigid as wood and requires a support structure with more joists placed closer together.

Pros and Cons of Cedar Decking

Natural cedar and redwood are amazingly workable materials. The wood is structurally stable and available in grades from select — which means no knots or blemishes — to knotty. You seldom need expensive select boards for decking. Lumber expert Josh Kou recommends heartwood common (con heart), a grade midway between select and knotty.

Most people intuitively appreciate the perks of cedar decking:

• Natural appearance: The many modern developments in wood decking alternatives notwithstanding, it’s hard to resist the allure of natural wood.
• Highly durable: As Kou puts it: “Heartwood common cedar and redwood command a premium for their expected durability in the face of rot, insect attack and weathering.”
• Can be restained and refinished: Cedar decking can last up to 20 years, and you can restore a cedar deck to as-new condition by sanding off the old finish, restaining and applying a new finish. That isn’t possible with composites.

As a natural material, cedar does have a few drawbacks built in by Mother Nature:

• Color fades: UV sunlight deteriorates the surface fibers and turns the wood gray after a year or two. You can forestall this loss of natural color by resealing, but ultimately, it’s a losing battle.
• Quality varies: Some boards are straighter and better-looking than others. Kou advises choosing boards that have had time to dry fully and to avoid warped ones. “If you hold up the end of a board, look along its length, and immediately recall the banana you ate the day before, put it to one side and select the next board.”
• Wood needs maintenance: As weather conditions change and temperatures fluctuate, wood can crack, curl and splinter. If you have a wood deck, you have to stay on top of developing defects by periodic cleaning and resealing.

Pros and Cons of Pressure-Treated Decking

Subjecting pine boards to chemical treatments under pressure produces a low-cost alternative to cedar. Modern chemical treatments are not as toxic as ones used in the past, so PT decking doesn’t pose the same environmental risks, but they aren’t zero.

Besides being the lowest-cost decking option, PT wood offers these bonuses:

• Outlasts natural wood: “PT boards will also last longer than untreated cedar or redwood,” says Kou. Many lumber retailers offer a limited warranty against rot and decay, provided the decking has been properly installed.
• Can touch the ground: Many PT decking products are rated for ground contact, which makes them the best choice for low decks with little or no clearance.
• Can be stained and sealed: If you don’t like the natural yellow color of PT decking, you can stain it. Like natural wood, PT decking benefits from a clear finish.

Some of the drawbacks of PT decking include:

• Must be kiln-dried: “Pressure-treated decking boards will shrink, split, crack and warp if they have not been properly kiln-dried,” says Kou. Not all PT wood is kiln-dried, so it’s important to read the label before you buy.
• Needs maintenance: PT wood is subject to the same effects of sun and weather as natural wood, and the deck’s appearance can deteriorate severely without periodic staining and resealing — or painting.
• Suffers checks and splintering: Even more than natural wood, PT wood is affected by moisture and extreme temperature changes, which can result in multiple tiny splits called checks, as well as splinters.

About the Expert

• Josh Kou has worked with lumber all his life. He is the operations manager for North Castle Hardwoods, which is based in Chicago, IL.