Cedar vs Composite vs PVC Decking in Rainy Oregon

For a deck in Sandy or anywhere on the wet side of the Cascades, the choice usually comes down to three kinds of boards: real cedar, composite (wood fiber and plastic), or PVC (all plastic). Any of them can make a good deck here. They differ in how they handle months of rain, how much upkeep they ask for, how they look as they age, and what they cost up front. Anthony builds with Trex, TimberTech, or cedar, whatever the homeowner picks, so the right answer is the one that fits how you use your yard.

The three materials in plain terms

• Western red cedar is real wood. The Western Red Cedar Lumber Association describes it as naturally resistant to rot, decay, and insects.
• Composite boards combine wood fiber and plastic. Trex makes its composite from "95% recycled plastic film and reclaimed sawdust," and TimberTech says its composite "combines real wood fibers with high-performance polymers," made with up to 85% recycled material.
• PVC boards have no wood at all. TimberTech says its Advanced PVC boards are "fully synthetic and resist moisture throughout the entire board."

How each one handles a wet climate

Cedar. Cedar's natural resistance to decay is why it has been a Northwest deck wood for so long. But no wood likes staying wet. The cedar association's own care guide puts it simply: "A deck that dries after wetting will last longer than one that stays damp." Good airflow under the deck, gaps between boards, and keeping moss and debris off all help.

Composite. Composite boards can still grow mold and mildew on the surface. Trex explains that mold feeds on the biofilm, the film of dirt and pollen that builds up on any deck surface, and recommends a hose, warm soapy water, and a soft bristle brush to remove it. Most TimberTech composite collections have a protective cap on all four sides; some have a three-sided cap. Trex says its top lines protect against fading, staining, scratching, mold, and mildew.

PVC. PVC boards have no wood fiber inside. TimberTech describes its Advanced PVC as offering "the highest level of protection against rot, mold, and mildew." It still gets dirty and still needs an occasional wash.

Whichever boards you choose, the framing underneath is usually pressure-treated wood. That means flashing at the house, good drainage, and airflow matter no matter what's on top. Our guide on how long a deck lasts in Oregon covers what to check.

Upkeep, side by side

• Cedar: The cedar association recommends cleaning the deck once a year in spring "to remove dirt, mildew and other forms of dis-coloration," and warns against power-washing because it damages the wood fibers. Left unfinished, cedar turns gray as it weathers. A finish changes how it ages; ask about the upkeep a finish needs before you choose one.
• Composite: Regular washing with soap and a soft brush. If you use a pressure washer, Trex says to stay at or below 3,100 psi with a fan tip held at least 8 inches from the surface.
• PVC: Washing, no finishing.

Heat on sunny days

Oregon summers are short, but a south-facing deck still gets hot in July and August. Trex says plainly that, "like all decking, it will get hot in direct sun on hot days, especially darker colors." TimberTech says the same about composite and suggests lighter colors to reduce heat. It claims its Advanced PVC stays up to 30 degrees cooler than competing composites. If the deck is in full sun and people go barefoot, color choice matters more than material.

Warranties

• Trex: limited residential warranties from 25 to 50 years, depending on the line. Select carries 35 years and Enhance 25 years.
• TimberTech composite: 25- and 30-year product, fade, and stain limited warranties, depending on the collection.
• TimberTech Advanced PVC: a limited lifetime product warranty and a 50-year fade and stain warranty.
• Cedar: how long it lasts depends on the build and the upkeep.

These are limited warranties. Read what each covers, and keep in mind they cover the boards, not the framing underneath.

How to choose

A few questions usually sort it out:

• How much upkeep do you want? If yearly cleaning and refinishing every few years sounds fine, cedar gives you real wood. If you'd rather just wash it, composite or PVC.
• How shady and damp is the spot? A deck under tall firs that never fully dries is where moisture resistance pays off most.
• What look do you want? Cedar weathers to gray unless it's finished. Composite and PVC hold their color longer.
• Budget. Material and labor costs vary by board line and deck design. Get a written bid that names the exact product line, not just "composite."

If you're planning a raised deck, check the Clackamas County deck permit rules before you settle on a design.