Manufacturing & Pultrusion Process
Inline Fiberglass is built around one material: fiberglass. As a vertically integrated fiberglass manufacturer, Inline controls key production steps including pultrusion, painting, assembly, and quality control.
Manufacturing Control Behind Better Fiberglass Windows
Our manufacturing process gives us greater control over the parts that matter most, from pultruded fiberglass lineals to painting, design, and final assembly. That control helps support product consistency, finish quality, thermal performance, and long-term durability across residential, commercial, and high-performance building projects.
When you choose pultruded fiberglass windows, you are not just choosing a frame material. You are choosing a manufacturing method designed for strength, dimensional stability, and performance-focused construction over time.
Why the Manufacturing Process Matters
Many window companies assemble products from materials made elsewhere. Inline’s advantage is different.
Inline controls key production steps including pultrusion, painting, assembly, and quality control. This gives the team greater control over product consistency, finish quality, and final inspection before completed window and door systems move forward.
This gives the team tighter control over quality, fit, finish, and product consistency before the finished unit reaches the project site.
For homeowners, that means windows and doors designed for comfort, durability, and clean design.
For architects, builders, and specifiers, it means clearer product confidence, better technical support, and a stronger basis for selecting fiberglass window frames for demanding projects.
How Pultruded Fiberglass Window Frames Are Made
Pultrusion is the process used to create strong fiberglass lineals for window and door frames.
Unlike vinyl extrusion, which pushes heated plastic through a die, pultrusion pulls continuous fiberglass reinforcement through resin and a heated die. The result is a rigid fiberglass profile that can be cut, finished, and assembled into high-performance window and door systems.
1. Continuous Fiberglass Reinforcement
The process starts with continuous strands of fiberglass. These strands are aligned to help create strength through the full length of the frame profile. This is one reason pultruded fiberglass windows are different from many vinyl windows. The frame is not simply shaped plastic. It is a fiber-reinforced material designed for structural stability.
2. Resin Saturation
The fiberglass reinforcement is drawn through a resin system. The resin surrounds the fiberglass strands and helps form the final composite material. This step matters because even saturation helps support strength, moisture resistance, and consistent material performance.
3. Heated Die Forming
The resin-coated fiberglass is pulled through a heated die. This shapes the material into the exact frame profile needed for Inline’s window and door systems. Inside the die, the material cures into a rigid fiberglass lineal.
4. Cooling and Cutting
After curing, the fiberglass profile is cooled and cut into specific lengths. These lineals then move into the next stages of production.
5. Painting, Design, and Assembly
The finished fiberglass lineals can be painted, prepared, and assembled into window and door units. This is where manufacturing control becomes especially important. Precise assembly helps support fit, sealing, finish quality, and long-term product consistency.
Built with Quality Control at Each Major Step
A premium window is only as strong as the process behind it.
Pultrusion
Fiberglass lineals are produced through a pultrusion process designed to create strong, stable frame profiles.
Painting and Applied Finishes
Inline can support custom colour requests, including any colour, subject to project review. AAMA coating references should only be used for applied finishes.
Assembly
Final assembly is part of Inline’s controlled manufacturing process and supports product consistency, fit, and finish.
Quality Control
Inline’s confirmed process includes quality control after pultrusion, painting, and assembly.
Technical Documentation
PDF and CAD drawings should be made available publicly where applicable. Exact file lists and URLs should be confirmed before publishing.
Product-Specific Certifications
Certification details for individual Inline window and door products, including performance standards, and energy-efficiency designations.
Stronger Fiberglass
Window Frames
Pultruded fiberglass frames are designed for strength and stability. This helps support larger glass areas, clean sightlines, and long-term frame performance. For projects where durability matters, fiberglass offers a serious advantage over materials that can move, warp, or expand more dramatically under temperature changes.
Better Dimensional Stability
Windows deal with heat, cold, wind, sun, and moisture. Frame movement can affect seals, operation, and long-term performance.
Fiberglass is valued because it expands and contracts less than many common window materials. That dimensional stability helps the frame hold its shape through changing conditions.
Improved Thermal Performance
Window frames are part of the building envelope. A weak frame can become a point of energy loss.
Fiberglass window frames help support energy-efficient design because the material is less conductive than aluminum and more stable than many vinyl alternatives. This makes fiberglass a strong fit for homeowners, architects, builders, and Passive House-minded projects.
Finish Flexibility
Inline can support custom colour requests, including project-specific colour matching opportunities. Because custom finishes may affect production requirements, finish availability, minimum order quantities, pricing, and lead times, final colour options should be reviewed and confirmed during the quote, specification, or project planning process.
Long-Term Value
Pultruded fiberglass windows are often chosen for their long-term value, not just their initial cost. Homeowners may prioritize comfort, durability, and lower maintenance, while architects, builders, and commercial project teams often value product confidence, frame stability, and long-term building performance.
Built for Homeowners, Architects, Builders, and Specifiers
Inline manufactures a broad fiberglass product lineup for different project needs.
For Homeowners
For direct-service projects, Inline has its own installers and can provide turnkey replacement service, including removal of existing windows and installation of new products tailored to the project. Dealer-supported or out-of-area projects should be confirmed with the Inline team.
For Architects and Specifiers
Get product details, technical documents, drawings, and performance information to help evaluate Inline fiberglass windows and doors for your project.
For Builders and Contractors
Send us your project details, drawings, or product requirements. Our team can help you confirm product fit and next steps.
For Commercial Projects
Inline supports commercial and high-performance project conversations with technical documentation and product guidance. Contact the team to confirm product fit, certification scope, and available documentation for your project.
Build with the
Strength of Fiberglass
The right window starts with the right frame material and the right manufacturing process. Inline Fiberglass makes pultruded fiberglass windows and doors for projects where strength, comfort, durability, and clean design matter. Tell us about your project and our team will help you take the next step.
Common Questions About Pultruded Fiberglass Windows
Find clear answers to common questions about Pultruded Fiberglass Windows.
What is pultrusion?
Pultrusion is a manufacturing process used to make strong fiberglass profiles. Continuous fiberglass reinforcement is pulled through resin and a heated die, where it cures into a rigid frame lineal.
For windows and doors, this process helps create fiberglass frames with strength, stability, and consistent shape.
Why are pultruded fiberglass windows different from vinyl windows?
Vinyl windows are made from plastic. Pultruded fiberglass windows are made from fiber-reinforced composite material.
That difference can affect strength, frame movement, temperature stability, finish quality, and long-term durability. Fiberglass is often selected for premium homes, custom builds, commercial projects, and high-performance building needs.
Why does fiberglass expand less than some other window materials?
Fiberglass is valued for dimensional stability. It responds to temperature changes differently than materials like vinyl or aluminum.
That matters because window frames are exposed to heat, cold, and moisture. Less frame movement can help support consistent fit and operation over time.
How are colours applied to fiberglass window frames?
Inline can support custom colour requests, including any colour, subject to project review. AAMA coating references are only assigned to applied finishes. Exact finish names, standard palette details, minimums, and lead-time impacts should be confirmed during the quote or specification process.
What affects long-term window durability?
Long-term durability depends on several factors, including frame material, glass package, manufacturing quality, installation quality, exposure conditions, maintenance, and correct product selection.
Pultruded fiberglass frames are designed to support long-term strength and stability, but the right product should always be confirmed for the project.
Are Inline products suitable for Passive House or high-performance projects?
Select Inline products are certified for Passive House-related performance needs. PHIUS applies to 325 SER CSM/AWN/FXD, 400 SER, and 3000 SER TNT/FXD. PHI applies to 3000 SER TNT/FXD. Contact Inline to confirm the right product, certification details, and documentation for your project.
Can I get technical documents or product specs?
Yes. Architects, builders, developers, and performance-focused buyers can request product specs, drawings, certification details, and technical support.