The three dominant brands in the capped composite decking market — Trex, Fiberon, and TimberTech — are all solid products when you buy the right product line from each manufacturer. The challenge is that each brand sells both capped and uncapped composites under the same brand name, and in Seattle's wet climate, the distinction between those two categories matters more than brand name alone. This guide cuts through the marketing language to explain which specific product lines we recommend for Pacific Northwest conditions, how they compare on price and warranty, and what we've observed in real-world Seattle installations across the past decade.
The Most Important Thing: Capped vs. Uncapped
Before comparing brands, you need to understand the fundamental distinction that separates composites that perform in Seattle from those that don't.
Composite decking is a blend of wood fiber and plastic binders. The original composite formulation, introduced broadly in the 1990s, left wood fiber exposed on the board's edges and underside. That exposed wood fiber absorbs moisture. In Seattle's persistent wet climate — where decks remain wet for extended stretches across fall, winter, and spring — moisture uptake through exposed wood fiber enables mold and mildew growth within the board structure. The result is the dark surface staining and early-stage degradation that gave first-generation composite products a poor reputation.
The industry's solution was the fully capped composite, introduced widely in the early 2010s. A fully capped board has a continuous polymer shell on all four sides that prevents moisture from reaching the wood fiber core. The board cannot absorb water, cannot develop internal mold growth, and maintains its surface appearance with minimal maintenance over the warranty period.
Uncapped composite still exists on the market today from every major brand, at meaningfully lower price points. The price difference is real. The performance difference in Seattle's climate is also real, and it becomes visible within two to three years of installation on a fully exposed deck.
Only specify fully capped composite for a Seattle-area deck. If a contractor or building materials salesperson recommends an uncapped line because it reduces the quote price, they are either unfamiliar with PNW climate performance or prioritizing a competitive bid over your long-term satisfaction. This is the most important purchasing decision in the composite category, and it applies equally across all three brands discussed here.
Trex
Trex is the most widely recognized composite brand in the United States, and its market presence across the Seattle area is strong. Trex is stocked at Home Depot locations throughout King County, which means accessible supply and competitive pricing through volume distribution.
The critical distinction within the Trex product lineup: Trex Transcend and Trex Enhance are fully capped composites with the polymer shell on all four sides. These are the Trex lines we specify and recommend for Seattle installations. Trex Select is only partially capped — the walking surface has a polymer cap, but the edges and underside are not fully sealed. Trex Select performs acceptably in dry climates with shorter wet seasons. It is not our recommendation for fully exposed Pacific Northwest conditions where boards remain wet for extended periods.
Trex Transcend carries a 25-year limited warranty covering fade, stain, and structural integrity on installed boards. The color palette is extensive — over twenty options across the Transcend line — and texture choices range from subtle wood grain to more prominent grain patterns that read convincingly as natural wood from a normal viewing distance. Trex Transcend has an established track record in King County. We have multiple installations in the six-to-ten-year age range that are performing as expected: no surface mold, consistent color, boards dimensionally stable.
The wide retail availability of Trex at Home Depot is both an advantage and something to manage carefully. The advantage is predictable lead times and competitive contractor pricing through high-volume distribution. The thing to manage: retail availability of Trex Select boards at the same locations as Trex Transcend means homeowners who purchase independently can inadvertently buy the wrong tier. When we specify Trex for a project, we confirm the exact product line and product number before any materials are ordered.
Fiberon
Fiberon carries less consumer brand recognition than Trex but holds an equal or better performance record in the installations we've completed with it. The Fiberon Symmetry and Fiberon Horizon lines are fully capped on all four sides and are our primary Fiberon specifications for Seattle-area work.
Fiberon typically prices slightly below Trex at equivalent product tiers. For homeowners working within a defined budget ceiling who want fully capped composite performance, Fiberon often represents the strongest value at the mid-market price point. The warranty structure on Fiberon's top lines is competitive: Fiberon Symmetry carries a 25-year fade, stain, and structural warranty. Fiberon's highest-tier Horizon products carry a lifetime fade and stain warranty, which is among the strongest coverage in the category.
We've monitored Fiberon Symmetry installations across multiple Seattle-area projects in the three-to-seven-year age range. Surface appearance remains consistent with new-installation appearance. No significant color shift, no surface mold, boards dimensionally stable through multiple PNW wet seasons. The board texture and color options have expanded substantially in recent product generations, with wood-grain patterns that are comparable to Trex Transcend in visual realism at normal viewing distances.
For clients who compare Fiberon Symmetry and Trex Transcend samples side by side and find Fiberon's aesthetics acceptable, the price difference — typically 8 to 15 percent at comparable specifications — is real money at project scale. A $35,000 project might see $3,000 to $5,000 in material cost savings by specifying Fiberon Symmetry over Trex Transcend, with equivalent climate performance.
TimberTech and AZEK
TimberTech and AZEK are owned by the same parent company, CPG, and understanding how the two brands relate to each other is important because they are fundamentally different products.
TimberTech is the composite line. Within TimberTech's product lineup, the PRO Collection and Legacy Collection are fully capped on all four sides. These are the TimberTech lines we specify for Seattle residential work. TimberTech is priced at the premium end of the capped composite market — above Trex Transcend and Fiberon Symmetry at equivalent tiers in most configurations. The warranty structure is competitive: 25-year fade and stain warranty on capped composite lines, with lifetime fade and stain coverage on the highest-tier Legacy products.
TimberTech's wood-grain texture and embossing depth are among the most realistic available in the capped composite category. For clients who want the natural wood appearance that composite can approximate — with more visible grain variation and texture depth than either Trex or Fiberon typically offer — TimberTech frequently wins the aesthetics comparison at design reviews. This is a preference factor, not a performance advantage. All three brands perform comparably at the fully capped tier.
AZEK is where our recommendation diverges most significantly from a standard composite comparison: AZEK is not composite. It is pure polyvinyl chloride — 100% synthetic, with no wood fiber content at all. This distinction is not cosmetic. A board with no wood fiber has no organic material for moisture to affect. It cannot absorb water through any surface. It cannot develop internal mold growth. Its dimensional stability across moisture cycling is significantly better than composite because there is no hygroscopic wood fiber component to respond to moisture changes.
AZEK carries a 50-year limited warranty, reflecting the expected product lifespan under demanding conditions. The maintenance requirement is essentially zero — an occasional rinse to remove surface debris is the full maintenance program for the product's lifetime. The price is the highest in the decking category, which is why AZEK is not our default specification for every project. It is our specification for high-performance applications where composite's slightly lower moisture resistance matters.
Our [PVC decking page](/pvc-decking) covers the full technical case for PVC versus composite in Seattle's climate. The short summary: for view decks, rooftop decks, waterfront applications in Bellevue or on Mercer Island, second-floor decks above living space, and any installation where sustained moisture exposure is above normal or maintenance access is limited — AZEK is the correct material and the one we specify.
Our Real-World Recommendation for Seattle Homeowners
After specifying all three brands across hundreds of King County projects and monitoring those installations over time, here is our practical guidance.
For the majority of Seattle homeowners — a standard elevated or ground-level deck on a typical residential lot with normal exposure — Trex Transcend and TimberTech Legacy are the two products we reach for first. Both are fully capped, both carry strong warranties, both have proven track records in Pacific Northwest conditions across many years of real installations, and both are reliably available through our local supplier network. The choice between them typically comes down to the client's color and texture preference at the design stage, since real-world performance is comparable.
Fiberon Symmetry is our recommendation when budget is a meaningful factor and the client wants a fully capped product at a lower price point than Trex Transcend or TimberTech Legacy. The performance record in our Seattle installations is strong, and the material savings are real.
AZEK is our recommendation for high-exposure, high-consequence applications — waterfront, rooftop, any elevated installation with sustained moisture exposure above the residential baseline, or any situation where the owner's lifestyle doesn't include periodic maintenance. It is the highest upfront cost and the best long-term value for those specific applications.
The consistent factor across all three brands for Seattle: specify only the fully capped lines. Trex Transcend or Enhance, not Select. Fiberon Symmetry or Horizon, not the entry tiers. TimberTech PRO or Legacy, not the lower lines. This decision matters more than which brand name is on the board.
We're certified installers for Trex, Fiberon, TimberTech, and AZEK, and we have current supplier relationships that give us visibility into product availability, lead times, and pricing. Visit our [composite decking page](/composite-decking) for an overview of the broader composite category, or [contact us](/contact) to get a specific product recommendation based on your site conditions, design goals, and budget.