Composite & PVC Decking

Composite vs PVC, and the actual difference

Composite boards are wood flour mixed with polyethylene, usually with a hard polymer cap on the visible faces. PVC boards have no wood in them at all. That one fact drives most of the practical difference. No organic content means nothing for moisture to feed on, and it means a lighter board that runs cooler than a dark composite of the same color.

Composite costs less and the capped lines are good products. PVC costs more and is the better answer near water, on decks that take hard all-day sun, and anywhere the owner wants to think about the deck as little as possible.

Where the brands stand

TimberTech absorbed AZEK, which is why you'll see the same PVC line sold under both names, TimberTech AZEK. It's the same board. If you have older AZEK on the property and want to match it, that's where to look.

Trex spent years without a PVC product while the market moved toward one. That gap is now closed. Trex Refuge, its ignition-resistant PVC board, now carries a California State Fire Marshal listing. Class A, tested to SFM 12-7A-4A, with a condition on the adjacent wall covering. It's a reasonable product and a legitimate fire-zone spec. More on how the State Fire Marshal listings work: fire-zone decking.

Fire zones narrow the field fast

If your property sits in a fire hazard severity zone, the deck walking surface has to comply with the California Wildland-Urban Interface Code, and most of the decision gets made for you.

TimberTech AZEK's Vintage and Landmark Collections are both listed Class A with no conditions attached. Trex Transcend, Select, Transcend Lineage and Refuge are all listed too, but each carries a condition: the exterior wall covering next to the deck has to be noncombustible or ignition-resistant. Trex Enhance isn't listed at all. It's a perfectly good board for a deck in Encino and it will get red-lined on a Palisades permit.

We check the specific product line, not the brand, against the State Fire Marshal's listing before it goes in a proposal.

Color, heat and honest expectations

Deck surface temperature comes down mostly to color and sun exposure, not to material category on its own. A dark board of any material runs hot in a Valley August. There's no independent published dataset comparing barefoot temperatures across hardwood, composite and PVC, so we're not going to quote you a number. Every "runs cooler" claim you'll see is a manufacturer's own test against unnamed competitors. What we will tell you is to look at a sample outdoors, in the sun, in the color you actually want, before you commit.

One thing about warranties that nobody hears at the point of sale. Trex's stain warranty requires the surface to be cleaned within seven days of a spill. It's in their own care documentation.

Installation is where these products get ruined

Composite and PVC move with temperature a lot more than wood does. That means gapping at butt joints and at the perimeter according to the manufacturer's schedule for the temperature on the day of install, hidden fasteners in the board's groove rather than face screws where the system calls for it, and joist spacing tightened to the manufacturer's specification. Often 12 inches on center for a diagonal layout or for stair treads, not the 16 inches people default to.

Get the gapping wrong and the deck buckles in July. That's an installation failure, not a product failure, and the warranty will say so.

Call (818) 345-2866.