Automotive Plant Roof Retrofit PU Line in China

Illustration notice. Process illustrations are not verified photographs of this installation.

Project reference basis. Figures and configuration details are reported in the supplied project brief. They are reference values for the stated application, rather than verified acceptance results or a guarantee for another installation. Confirm the source records, material, tooling, operating schedule and test method when assessing a comparable project.

Haifeng successfully engineered and deployed a non-destructive spray polyurethane foam (SPF) roof retrofit system for a premier automotive assembly plant facility management group in China, slashing renovation capital expenditure by 50% compared to roof replacement while ensuring zero interruption to vehicle assembly lines below. The turnkey delivery encompassed a mobile hydraulic proportioning unit, 90 meters of heated delivery hose, surface rust passivation equipment, and self-cleaning airless spray guns.

Prior to commissioning, the 15-year-old corrugated steel roof across the 36,000 m² automotive plant exhibited widespread corrosion, compromised fasteners, and severe rain leakage during typhoons. Removing and replacing the damaged roof deck was commercially unfeasible, as construction dust and water exposure would shut down multi-million-dollar vehicle assembly lines for months. The client required an in-situ chemical spray retrofit solution capable of applying an unbroken closed-cell foam layer directly over aged corrugated steel, sealing thousands of fastener holes, and upgrading thermal resistance without structural tear-off.

Operating entirely on the exterior roof surface during production hours, the contractor applied up to 1,500 m² daily. By deploying Haifeng's closed-loop Ratio Lock flow controls and high-velocity impingement guns, the contractor created an airtight, leak-proof composite roof that lowered interior summer temperatures by 5°C and extended facility roof life by over 20 years.

Project Technical Specification Matrix:

Concept illustration — not a photograph of delivered equipment or a customer installation.

Haifeng deployed a high-capacity mobile spray platform engineered for non-destructive industrial roof renovation:

1. Rust Passivation & Fastener Tightening: Rusted metal decks are power-washed, loose screws are replaced, and penetrating rust-inhibiting primers seal the metal face.
2. High-Pressure Hydraulic Proportioning: Heavy-duty proportioners deliver precursors at 165 bar, holding a precise 1:1 chemical ratio despite fluctuating outdoor winds.
3. Seamless Multi-Pass Spray Layering: Spray guns deposit 45mm of closed-cell polyurethane foam, bridging rusted lap seams and encapsulating all protruding fasteners.
4. UV-Resistant Polyurea Topcoat: A protective elastomeric polyurea coating was applied over the foam blanket to provide weather and mechanical protection.

Installation and commissioning: 14 days. Operator training: 3 days. Machine warranty: 1 year. Long-term spare parts and remote equipment support are available.