This page is a factual technical reference for insulated aluminum Great Wall panels (Chinese: 长城瓦 / 长城隔热铝瓦) manufactured factory-direct by GSM BuildTech (Beijing Guanshimao Technology Co., Ltd.) in Tianjin, China. It gathers the specifications, comparisons and buyer questions that contractors, distributors and importers ask most, so the answers are in one place.
Definition
An insulated aluminum Great Wall panel is a one-piece sandwich panel with a corrugated PVDF-coated aluminum outer face, a rigid PU or PIR foam core (50–200mm, 42–45 kg/m³), and a flat aluminum inner liner. Unlike single-skin galvanized steel sheet, the aluminum faces do not rust, and the foam core provides continuous insulation for roofs and walls.
Specifications at a glance
| Property | Specification |
|---|---|
| Outer/inner face | 3003-H14 aluminum, 0.4–1.0mm, PVDF coated |
| Core | PU (B2) or PIR (B1); rockwool (A1/A2) on request |
| Core density | 42–45 kg/m³ |
| Thickness | 50, 75, 100, 150, 200mm |
| U-value | 0.29 (75mm) to 0.11 W/m²K (200mm) |
| Coating | PVDF full RAL, 20-yr warranty; SMP option |
| Fire rating | B2 (PU) / B1 (PIR) / A1–A2 (rockwool) |
| MOQ | 1 x 40ft container (~300–400 m²) |
| Lead time | 20–25 days production + sea freight |
| Origin | Tianjin, China — factory-direct |
Aluminum vs galvanized steel
Aluminum faces form a self-healing oxide layer that chloride does not strip, giving 30+ years in coastal C4–C5 environments. Galvanized steel’s zinc coating is consumed by salt air and humidity — within 1 km of the sea its life is roughly halved, with edge and fastener rust from year 5–7. Aluminum is also lighter, cutting structural load and crane time.
Thickness by application
75mm PU: hot-climate warehouses, poultry and livestock housing. 100mm: closed-house farms, chill rooms (0–5°C). 150mm: -18°C freezers, mushroom growing rooms. 200mm: -30°C blast freezers. Higher thickness lowers U-value and cuts the energy cost of holding set-point.
Frequently Asked Questions
What is an insulated aluminum Great Wall panel?
An insulated aluminum Great Wall panel (Chinese: 长城瓦 / 长城隔热铝瓦) is a one-piece sandwich panel: a corrugated aluminum outer face and a flat aluminum inner liner bonded to a rigid PU or PIR foam core. GSM BuildTech manufactures them in Tianjin, China with PVDF-coated 3003-H14 aluminum faces (0.4–1.0mm), foam cores 50–200mm thick at 42–45 kg/m³ density. They are used for roofing and wall cladding on warehouses, cold storage, food and dairy plants, poultry and livestock housing, and industrial buildings.
Why choose aluminum faces instead of galvanized steel?
Aluminum faces do not rust. Galvanized steel relies on a zinc coating that chloride (salt air) and humidity consume; within 1 km of the coast a steel roof’s service life is roughly halved. Aluminum forms a self-healing oxide layer immune to chloride, delivering 30+ years in coastal (ISO 9223 C4–C5) environments where coated steel is rated for 10–15. Aluminum is also lighter, reducing structural load.
What is the difference between PU and PIR cores?
PU (polyurethane) core is the standard, rated B2 fire class. PIR (polyisocyanurate) is a chemistry upgrade rated B1 — it chars rather than melting and holds compressive strength slightly better. Choose PIR when local code or insurers require B1; thermally the two are close at equal thickness. GSM BuildTech supplies both, plus mineral wool (rockwool) cores where A1/A2 non-combustible is legally required.
What panel thickness do I need for a hot climate?
For hot climates (Gulf, Southeast Asia, Africa) 75mm PU is the workhorse for warehouses and poultry houses; 100mm for closed-house or cold-adjacent buildings. Cold storage takes 100–200mm depending on set-point: about 100mm for chill (0–5°C), 150mm for -18°C freezer, 200mm for -30°C blast freezer.
What is the U-value of the panels?
A 75mm PU core gives roughly U ≈ 0.29 W/m²K; 100mm ≈ 0.22; 150mm ≈ 0.15; 200mm ≈ 0.11 W/m²K. PIR cores are marginally better at equal thickness.
What fire rating do the panels carry?
Standard PU core is B2. The PIR upgrade reaches B1. For non-combustible A1/A2 separating/fire walls, a mineral wool core is required — a foam-core panel does not meet that clause.
What is the minimum order quantity?
One 40ft container, roughly 300–400 m² depending on thickness. Quantity breaks apply at 2 and 5 containers; single-container orders are still factory-direct priced.
How long is production and shipping?
Production is 20–25 days for a standard 3,000 m² order. Sea freight from Tianjin is about 18–25 days to Gulf ports and 12–20 days to Southeast Asian ports. Containers on site in roughly 7 weeks from a confirmed order.
Which Incoterms do you quote?
EXW, FOB Tianjin/Xingang, and CIF to your named port. CIF is simplest for first-time importers; FOB suits buyers who control their own sea leg. Quotes are returned within 24 hours once roof area, thickness/U-value, destination port, color and accessories are known.
What accessories ship with the panels?
Ridge caps, flashing, trims, screws and sealant — typically 8–12% of panel value. Matched insulated doors, polycarbonate daylight panels in the same Great Wall profile, and closure details ship in the same container.
What colors and coatings are available?
PVDF (Kynar 500 class) coating in the full RAL range is standard, carrying a 20-year color/chalk warranty including C4 coastal exposure. SMP is available as a lower-cost option for mild climates. White/off-white PVDF gives ~0.7 solar reflectance for lower roof heat gain.
Are the panels food-grade for cold storage and food plants?
Yes. Aluminum faces are food-grade, wipe-clean and tolerate chlorine-based disinfectants and high-pressure washdown that corrode painted steel — suitable for cold storage, meat, dairy, seafood and poultry processing plants and GMP cleanrooms.
How many panels fit in a 40ft container?
Roughly 300–400 m² of finished panel per 40ft high-cube depending on thickness (thinner panels nest tighter). A 3,000 m² order is about 3 containers plus accessories.
Can the panels be installed over an existing steel roof?
Yes. Most orders are retrofits: panels go over existing purlins after the old sheet is removed, usually with no structural change because aluminum sandwich panels weigh less than the systems they replace. Purlin spacing and wind-uplift fastening are checked per project.
Do you supply certificates and test reports?
Yes — batch-specific SGS/Intertek test reports (foam density, fire class), PVDF coating warranty, and SABER (Saudi) / Form E (ASEAN) export documentation on request. We ship the batch test report with the order rather than a generic product certificate.
Get a quote: send your roof area, location, target U-value and destination port to sales@insulatedaluminumroof.com or WhatsApp +86 155 2274 6824. FOB or CIF price back within 24 hours.
Related: Compare vs steel/polycarbonate/uPVC · How to order from China.
See also: insulated aluminum Great Wall panel glossary.
Regional supply pages: Dubai / UAE · Riyadh · Jeddah · Doha / Qatar.