Why uPVC Thermoplastic Roofing is Replacing Corrugated Metal Sheets
TL;DR Summary
Traditional galvanized iron (GI) roofing sheets corrode quickly when exposed to salt air, chemical fumes, and animal waste. uPVC thermoplastic roofing provides a 100% rust-proof, heat-insulating, and noise-damping alternative. Co-extruded with an ASA weather layer, it retains its color and structural strength for decades.
uPVC Thermoplastic Roofing Advantages have made this advanced polymer system the modern standard for commercial warehouses, chemical plants, livestock farms, and coastal properties in the Philippines. Galvanized iron (GI) sheets quickly rust when exposed to extreme marine humidity and industrial vapors, requiring frequent, expensive replacements.
The Problems with Metal Roofing
Metal roof panels are highly susceptible to oxidation. When rain mixes with coastal salt air or acid rains, it creates an electrolytic cell that strips zinc coatings and rusts the iron base. In addition, metal roofing offers very poor thermal insulation, transmitting solar heat directly into structures and forcing up building cooling costs.
Why uPVC Roofing is Superior
1. Complete Corrosion Resistance
uPVC (unplasticized Polyvinyl Chloride) is a non-conductive plastic polymer. It cannot rust, oxidize, or corrode. It easily resists sulfur dioxide, nitric acid fumes, marine salts, and ammonia gases (commonly found in poultry and piggery farms).
2. Thermal and Acoustic Insulation
uPVC has a very low thermal conductivity rating compared to steel. A uPVC roof sheet can reduce interior temperatures by up to 5°C to 8°C. During heavy tropical storms, it dampens acoustic vibrations, lowering rain impact noise by up to 30 decibels compared to echoing metal roofing.
3. ASA Weather Protection
Premium thermoplastic sheets are manufactured using multi-layer co-extrusion. The top layer features an Acrylonitrile Styrene Acrylate (ASA) coating. ASA provides extreme resistance to ultraviolet (UV) radiation, protecting the roof from cracking, warping, and fading under hot sun exposure.
uPVC vs. Metal Roofing Comparison
| Feature / Property | uPVC Thermoplastic Roofing | Galvanized Iron (GI) Sheets |
|---|---|---|
| Rust & Corrosion | 100% Corrosion Proof (Lifetime) | Highly susceptible to rust and chemical attack |
| Heat Conductivity | Very Low (Excellent natural insulator) | Very High (Heats up the building interior) |
| Noise Damping | Excellent (Reduces storm noise up to 30dB) | Very Poor (Echoes loudly during rainfall) |
| Lifespan in Coastal Sites | 25+ Years without degradation | 3 – 5 Years before rust holes develop |
| Maintenance | Virtually zero (Self-cleaning with rain) | High (Requires periodic anti-rust paint) |
Ideal Applications
Due to its resilience, uPVC roofing is heavily utilized in: chemical processing complexes, fertilizer warehouses, sea-salt processing buildings, coastal beach resorts, and agricultural livestock structures where animal waste creates highly corrosive ammonia gas environments.
Frequently Asked Questions (FAQ)
Q1: Does uPVC roofing expand under the sun?
A1: Yes, like all thermoplastics, uPVC expands and contracts slightly with temperature changes. Roof installers must use oversized pre-drilled holes to allow for minor thermal movements.
Q2: Can you walk on uPVC roofing sheets during installation?
A2: While uPVC is highly impact-resistant, workers should use crawl boards or walk directly over the purlin supports for safety, never stepping on the center of unsupported spans.
Q3: Is the ASA co-extrusion coating worth the cost?
A3: Yes. The ASA layer acts as a premium sunblock shield, preventing UV radiation from degrading the polymer chains, preserving the roof’s elasticity and color.
Q4: How does uPVC roof weight compare to metal?
A4: uPVC sheets are lightweight and easy to handle, reducing structural load demands and simplifying transportation and hoisting logistics.
Q5: Is uPVC roofing fire retardant?
A5: Yes, uPVC has natural self-extinguishing properties (Class B1 fire rating). It will not fuel a fire and stops burning once the external flame source is removed.