If you've gotten deck quotes in King County recently, you've probably seen both TimberTech and AZEK on the same proposal. That's not a mistake or a contractor mixing up brands. Both are products of The AZEK Company — they share a manufacturer, a distributor, and frequently the same installer network. But they are not the same product, and in Seattle's climate, the distinction matters.
Here's what most homeowners don't realize: TimberTech is the composite line, and AZEK is the PVC line. The material difference — wood fiber in the core versus 100% cellular PVC — is significant when your deck will see 37+ inches of rain per year and may stay damp for days at a stretch.
What's the Same — and What's Actually Different
The AZEK Company owns both brands. They share distribution channels, certified installer programs, and often the same showroom samples. What differs is the material composition.
**TimberTech composite products** (including TimberTech PRO, TimberTech Edge, and TimberTech Legacy) are made from a combination of wood fiber and recycled plastic, fully encased in a polymer shell. The "capped composite" construction means the wood fiber core is protected on all four sides from direct moisture contact — a critical specification in the PNW. TimberTech pioneered 4-sided capping technology and is one of the few composite lines we confidently specify for King County conditions.
**AZEK products** (including AZEK Vintage, AZEK Harvest, and AZEK Arbor collections) are 100% cellular PVC — no wood content at all. There is no fiber core to absorb moisture, because there is no fiber. It's solid polymer through and through.
Both products resist moisture significantly better than uncapped composites or cedar. But they do it through different mechanisms, and they come with different price points, warranties, and long-term performance profiles. If you're comparing either of these brands to other manufacturers, see our [Trex vs. Fiberon vs. TimberTech guide](/blog/trex-vs-fiberon-vs-timbertech-seattle) for the broader brand landscape.
How Seattle's Climate Changes This Comparison
A comparison guide written for Phoenix or Charlotte doesn't apply here. King County averages 37–38 inches of rain per year — more than New York, Boston, and Miami. Decks in Seattle spend 6+ months under sustained moisture exposure, not the occasional afternoon shower. The material composition of your decking boards is a meaningful long-term performance variable at this latitude.
**With capped composite (TimberTech PRO):** The wood fiber core is shielded by the polymer cap. Properly manufactured and installed — with cut ends sealed and approved fasteners at the right spacing — capped composite handles Seattle rain well over a 20–30 year lifespan. Where the system can fail: cut ends and fastener penetrations that expose fiber and aren't end-sealed at installation. A certified installer applies end-sealant to every cut. An uncertified installer often skips it. This matters more in Seattle than anywhere south of Portland.
**With AZEK PVC:** There is no wood fiber to protect. Water has nowhere to absorb — the board is solid polymer. This matters most on heavily shaded lots (common in Issaquah foothills, Sammamish woodland neighborhoods, and tree-canopy-dense pockets of North Seattle) where moisture lingers on deck surfaces for extended periods. On lots where the deck never fully dries between rain events, AZEK's full-polymer construction eliminates the moisture absorption variable entirely.
Seattle's lower sun angle also affects UV fade differently than sunbelt climates. AZEK's 50-year fade and stain warranty reflects polymer color stability that holds longer than most composite lines — including TimberTech's composite products — in north-facing and heavily shaded exposures. For more on how PNW climate should drive material selection, see our [best decking materials for Seattle guide](/blog/best-decking-materials-seattle-2026).
Warranty and Durability Side-by-Side
| Category | TimberTech PRO (Composite) | AZEK (PVC) | |---|---|---| | Material Composition | Capped wood fiber + polymer | 100% cellular PVC | | Fade & Stain Warranty | 30 years | 50 years | | Structural Warranty | 30 years (residential) | Limited Lifetime (residential) | | Moisture Absorption | Low (fully capped) | Virtually zero | | Shaded Lot Performance | Good | Excellent | | Moss/Mildew Resistance | Good | Excellent | | Heat Retention | Moderate | Stays cooler than many composites | | Certified Install Required for Warranty | Yes | Yes |
For most Seattle homeowners, both warranties exceed the realistic life expectancy of the deck. The practical difference surfaces on heavily shaded lots, rooftop applications, or properties near Puget Sound where salt air and sustained moisture are constant site conditions.
Price Comparison: What to Budget in King County
Installed costs in King County (material + labor + fasteners, excluding permit and demo):
| Product Line | Material Cost/Lin. Ft | Installed Est./Sq. Ft | |---|---|---| | TimberTech Edge (composite, entry) | $5.70–$7.50 | $28–$40 | | TimberTech PRO (composite, mid-high) | $9.00–$12.00 | $38–$52 | | AZEK Vintage/Harvest (PVC) | $11.00–$13.50 | $45–$60 |
The AZEK premium over TimberTech composite runs 15–25% in material cost. On a 350 sqft deck, that difference is $2,500–$4,500 in material — before labor, which is comparable for both products. For full Seattle deck pricing by project type and material, see our [deck cost guide](/deck-cost-seattle).
Which Should You Choose for Your Seattle Deck?
Neither product is universally correct. The right choice depends on your lot conditions, budget, and how the space will be used.
Choose TimberTech Composite (PRO or Edge) When:
- Your deck gets 4+ hours of direct sun daily — full sun exposure reduces the moisture-lingering concern for composite - Budget is a primary factor — TimberTech PRO delivers excellent 30-year performance at a lower price point than AZEK - You're building a ground-level deck with proper drainage slope built in - You're replacing a cedar deck and the project budget centers on $30,000–$45,000 for a 300 sqft build
Choose AZEK PVC When:
- Your lot has heavy tree canopy and the deck stays damp for multiple days after a rain event - You're building a rooftop deck or elevated application where water management is the primary design challenge — see our [composite vs. PVC decking page](/composite-decking) for rooftop-specific specs - You want the longest available warranty and a true zero-maintenance material profile over decades - The project is a premium build — Mercer Island view deck, Bellevue hillside, Sammamish Plateau outdoor room — where the homeowner wants the best available specification regardless of the price premium
For guidance on whether [PVC decking](/pvc-decking) or [composite decking](/composite-decking) aligns with your specific project, our consultations include a lot assessment that accounts for shade, drainage, and site exposure — not just material price.
The Installer Matters as Much as the Brand
Both TimberTech and AZEK require certified installation to validate their manufacturer warranties. The certification covers end-sealing requirements, approved fastener systems, minimum joist spacing, and drainage slope standards. An uncertified installer can put down either product, but the manufacturer warranty is voided on uncertified installs — and homeowners usually don't find out until a warranty claim is filed.
We're certified installers for both TimberTech and AZEK products. When we specify either line for your project, the warranty transfers to you and we document the certified install for your records and future resale. Our 5-year workmanship warranty covers installation independently of the manufacturer coverage.
In Seattle's climate, installation technique matters as much as brand selection. A perfectly engineered composite board underperforms if cut ends aren't sealed and drainage slope isn't built into the framing. Neither detail is visible after installation — which is why certified installer documentation is the only reliable signal that the install was done to spec.
Our Recommendation for Most Seattle Homeowners
For most King County lots with reasonable sun exposure: **TimberTech PRO composite** is the right call. The performance is excellent in Seattle conditions, the 30-year warranty covers nearly any realistic deck lifespan, and the price is meaningfully lower than AZEK PVC.
For heavily shaded lots, rooftop applications, or homeowners who want the maximum possible lifespan with zero maintenance overhead: **AZEK PVC** is worth the premium.
In both cases, you're choosing the material category — composite versus PVC — not just a brand name. Both The AZEK Company lines execute their respective categories well. What differentiates a Seattle deck that lasts 35 years from one that shows problems at 8 is installation quality, correct material specification for the site, and proper drainage design — factors that have nothing to do with which box the boards came in.
Have questions about which product fits your lot? Our [FAQ page](/faq) covers common material questions, or call us directly.
Get a free deck estimate from The Seattle Decking Company — call **(425) 675-6259** or [request your estimate](/contact).