## Common ground
All options refer to window frames classified by their primary material.
## Options at a glance
**3925.20 – Plastic**
- **Defining trait:** Made primarily from synthetic plastic (e.g., PVC).
- **Typical examples:** PVC window frames, uPVC sashes.
- **Best fit when:** Lightweight, weather-resistant, low-maintenance frames are needed.
**4418.1X/2X – Wood**
- **Defining trait:** Made from natural wood (softwood or hardwood).
- **Typical examples:** Solid timber frames, wooden casement windows.
- **Best fit when:** Aesthetic warmth, traditional look, or high insulation is desired.
**6802.2X/9X – Stone**
- **Defining trait:** Made from natural stone (e.g., marble, granite) used structurally.
- **Typical examples:** Stone-framed windows in historic buildings.
- **Best fit when:** Architectural uniqueness or durability in high-end construction.
**6810.99 – Cement Concrete / Artificial Stone**
- **Defining trait:** Made from cement-based materials, often molded.
- **Typical examples:** Concrete window frames, precast stone units.
- **Best fit when:** High fire resistance, heavy-duty use, or industrial design.
**6811.89 – Asbestos Cement / Cellulose Fiber Cement**
- **Defining trait:** Made from cement mixed with fibrous reinforcement (now largely phased out).
- **Typical examples:** Older industrial or utility building frames.
- **Best fit when:** Identifying legacy construction materials; avoid for new builds.
**7308.30 – Iron / Steel**
- **Defining trait:** Made from ferrous metal, often with protective coating.
- **Typical examples:** Steel-framed windows in commercial buildings.
- **Best fit when:** High strength, security, or large window spans required.
**7508 – Nickel**
- **Defining trait:** Made from nickel or nickel alloys (rare and expensive).
- **Typical examples:** Specialized marine or chemical-resistant frames.
- **Best fit when:** Extreme corrosion resistance in harsh environments.
**7610.10 – Aluminium**
- **Defining trait:** Made from lightweight, corrosion-resistant aluminum alloy.
- **Typical examples:** Modern curtain walls, sliding windows.
- **Best fit when:** Energy efficiency, modern design, and long lifespan are key.
**7907.00 – Zinc**
- **Defining trait:** Made from zinc or zinc alloys (often used for decorative finishes).
- **Typical examples:** Zinc-clad window frames in high-end architecture.
- **Best fit when:** Aesthetic appeal, weathering to a patina, or premium finish.
## Key differences
| Material | Weight | Durability | Common Use | Maintenance |
|----------------|------------|------------|--------------------|-------------|
| Plastic | Light | Medium | Residential | Low |
| Wood | Medium | Medium | Traditional homes | High |
| Stone | Heavy | Very High | Historic buildings | Low |
| Concrete | Heavy | Very High | Industrial | Low |
| Cement Fiber | Medium | High | Older buildings | Medium |
| Steel/Iron | Heavy | Very High | Commercial | Medium |
| Nickel | Medium | Extreme | Specialized | Low |
| Aluminium | Light | High | Modern architecture | Low |
| Zinc | Medium | High | Premium design | Low |
## How to choose
- Is the frame made of plastic (e.g., PVC)? → 3925.20
- Is it solid wood? → 4418.1X/2X
- Is it made from stone or concrete? → 6802.2X/9X or 6810.99
- Is it metal and lightweight (e.g., aluminum)? → 7610.10
- Is it iron, steel, or heavy-duty metal? → 7308.30
- Is it zinc or nickel? → 7907.00 or 7508
## Overlaps & pitfalls
- **Aluminum vs. steel:** Both are metals; aluminum is lighter and more corrosion-resistant.
- **Cement concrete vs. artificial stone:** Often indistinguishable in use; both fall under 6810.99.
- **Zinc vs. nickel:** Rare; zinc is common in architecture, nickel is niche.
- **Asbestos cement (6811.89):** Avoid due to health risks; only relevant for retrofits or historical assessment.
- If multiple materials are used (e.g., aluminum frame with wooden cladding), prioritize the **main structural material**