We build custom homes across the Columbia River Gorge. We spec windows on every single project. And last year, we spent a day at the Andersen Windows and Doors manufacturing facility in Goodyear, Arizona, walking the production line and looking closely at how Fibrex composite is actually made.
This is what we learned, and what it means for your home.
What Is Fibrex? (The Short Answer)
Fibrex is Andersen’s proprietary composite material made from two ingredients: reclaimed wood fiber and thermoplastic polymer. The wood fiber comes from Andersen’s own manufacturing waste, which keeps it out of landfills. The thermoplastic binds it into a rigid, stable frame material.
The result sits between wood and fiberglass in terms of behavior. It is not pure plastic, not traditional wood, and not fiberglass. It is its own thing, and once you understand what it does under stress, you start to see why it matters in certain builds.
Fibrex vs. Vinyl: The Numbers That Matter
Most comparisons between these two materials stay vague. Here is what the actual data looks like.
| Property | Fibrex | Vinyl (PVC) |
| Thermal expansion coefficient | ~0.0000038 in/in/F | ~0.0000380 in/in/F |
| Relative expansion vs. Fibrex | 1x (baseline) | ~8x more movement |
| Frame strength | Higher rigidity | More flexible |
| Frame width for same opening | Narrower possible | Wider required |
| Field modification (cutting, trimming) | Limited | Easier |
| Minor damage repair | Component replacement | Easier to patch |
| Average lifecycle in harsh climates | 30+ years (Andersen warranty) | 15-25 years typical |
| Upfront cost vs. vinyl | 15-30% higher | Lower baseline |
| Color options | Factory-applied, limited palette | Wider range |
| Paintable | No | Some products yes |
That thermal expansion number is the one most people do not know about. Vinyl expands and contracts at roughly eight times the rate of Fibrex when temperatures swing. In a mild climate, that barely matters. In the Gorge, where we regularly see 40-degree swings between morning and afternoon on summer days, it matters a lot.
What We Saw at the Factory?
Walking the Andersen production line changes how you think about windows. The Fibrex material goes through an extrusion process that looks more like aluminum fabrication than anything you would associate with plastic windows. The frames come out dense and rigid. When you pick one up, it does not flex the way vinyl does.
A few things stood out to us specifically.
The wood fiber content gives the material a different surface texture than vinyl. It holds fasteners better, which is why Fibrex can be manufactured with thinner profiles while maintaining structural integrity. Thinner profiles mean more glass area for the same rough opening size.
The factory tour also made the sustainability story concrete. Andersen recovers wood fiber from its own production and reintroduces it into Fibrex. That is not a marketing copy. You can see the recovered material in the process.
The production tolerances are tight. Every frame we looked at had consistent wall thickness, which translates directly to consistent seal performance over time. With vinyl, inconsistent wall thickness is one of the reasons seals fail early in cheaper products.
Why Window Frame Material Matters More in the Pacific Northwest?
The Gorge is a demanding environment for building materials. Here is what your windows deal with year-round in the White Salmon, Hood River, and Stevenson area:
- Temperature range: Average lows in the 20s (F) in winter, highs pushing 100 F in summer. That is an 80-degree seasonal swing, and daily swings in spring and fall can hit 40 degrees.
- Wind: The Gorge is one of the premier windsurfing destinations in the world for a reason. Consistent wind pressure puts stress on window seals and frames that most other climates do not.
- Moisture: Western exposure brings moisture from Pacific systems, while summer brings dry heat. Frames that absorb moisture and then dry out repeatedly tend to fail faster.
Under these conditions, a frame that expands and contracts significantly with temperature creates a cycle of stress on the glass seal unit. Over time, that stress is what causes seal failures, fogging between panes, and visible frame distortion in larger openings.
In the custom homes we have built in this area, the windows that have failed earliest have almost always been lower-grade vinyl in large openings or west-facing applications.
When Fibrex Makes Sense for Your Build?
Fibrex is not always the right call. Here is how we think about it on a project-by-project basis.
Choose Fibrex when:
- You have large window openings (floor-to-ceiling, wide picture windows, or corner configurations)
- The home has significant west or south exposure
- You are building for long-term ownership and want to minimize future maintenance
- Views are central to the design and you want maximum glass-to-frame ratio
- The project has a premium finish level overall
Vinyl still makes sense when:
- The project has a strict budget and large windows are not a priority
- The home has primarily north or east-facing window exposure
- It is a shorter-term investment (rental property, spec build for resale)
- Window openings are standard residential sizes without large expanses
Neither material is a bad choice in the right context. The mistake we see is when people choose vinyl for a high-end custom build with large west-facing openings and then wonder, eight years later, why seals are failing.
Frequently Asked Questions
Are Fibrex windows worth the extra cost?
For most custom homes with large openings or demanding climate exposure, yes. The upfront premium is typically 15 to 30 percent over comparable vinyl, but the performance difference shows up in lower maintenance, longer seal life, and less frame movement over time. For smaller, standard-size windows in protected exposures, the difference is less significant.
What are the disadvantages of Fibrex windows?
The main drawbacks are cost, limited field modification, and color options. Fibrex costs more than vinyl upfront. It cannot be easily trimmed or adjusted on-site if rough openings are off, so precision framing matters more. The factory-applied color palette is more limited than vinyl, and Fibrex cannot be painted after installation.
How long do Fibrex windows last?
Andersen backs Fibrex products with a 20-year warranty. In real-world performance, the frames themselves tend to outlast the warranty significantly. Seal unit lifespan depends more on installation quality and exposure than the frame material, but the reduced expansion and contraction cycle in Fibrex does extend average seal life versus vinyl in the same conditions.
Can you paint Fibrex windows?
No. Fibrex has a factory-applied finish that is not designed to accept exterior paint. If color flexibility is important to your project, vinyl or wood-clad options give you more options post-installation.
How much do Fibrex windows cost compared to vinyl?
Rough budget range for Fibrex in a custom home is $800 to $1,400 per window installed, depending on size and configuration. Comparable vinyl products typically run $500 to $900 installed. These are ballpark figures. Your actual cost depends on window size, quantity, installation complexity, and your specific product selection.
When should I choose vinyl over Fibrex?
When budget is the primary constraint and the project does not include large openings or severe climate exposure. Vinyl is a legitimate, widely-used window material. It performs well in standard applications. The cases where it underperforms relative to Fibrex are specific: large openings, high thermal stress, premium build quality expectations.
What is Fibrex made of, exactly?
Fibrex is 40 percent reclaimed wood fiber and 60 percent thermoplastic polymer by weight. The wood fiber comes from Andersen’s own manufacturing operations. The thermoplastic is the same family of material used in vinyl windows, but the combination behaves differently than either material alone.
How We Spec Windows at Quad Construction?
On every custom home project, we talk through window selection with our clients before framing starts. The window specification affects structural rough opening sizes, exterior trim details, and in some cases, structural header sizing for large openings.
We work with Andersen products regularly and have relationships with their local representatives. If you are early in the planning process, we can walk you through specific product options, pricing ranges for your design, and what the installation requirements look like for your particular site.
We build custom homes in White Salmon, Hood River, Stevenson, The Dalles, and across the Columbia River Gorge. If you are planning a build in this area, schedule a free consultation and we can talk through your window spec as part of the broader project conversation.
Quad Construction is a custom home builder based in White Salmon, WA. We have built homes throughout the Columbia River Gorge for over a decade.
