Great Wall aluminum panels are designed for fast, clean installation with concealed fixings. Done correctly, a small crew installs 500-800 m² a day with a watertight, fastener-free surface. Done wrong, you get leaks and thermal bridging. This guide covers the essentials.
1. Purlin Spacing
Purlin spacing depends on panel thickness and wind load. As a general reference for Great Wall PIR roof panels:
| Panel thickness | Typical max purlin spacing |
|---|---|
| 50mm | 1.2 – 1.5 m |
| 75mm | 1.5 – 2.0 m |
| 100mm | 2.0 – 2.5 m |
| 150mm | 2.5 – 3.0 m |
High wind-uplift zones (coastal Gulf, typhoon-prone Southeast Asia) require tighter spacing. Always confirm against a project wind-load calculation.
2. Laying Direction and Concealed Fixing
- Start laying from the side opposite the prevailing wind so laps face away from driving rain
- Each panel’s male tongue slides into the previous panel’s female groove
- Drive the self-drilling fastener through the fixing flange inside the joint – it is then hidden by the next panel
- Do not over-tighten: the fastener should seat the panel without crushing the rib
3. Fasteners
Use self-drilling screws sized to the purlin gauge, with EPDM-bonded washers. For aluminum panels on steel purlins, stainless or coated carbon-steel fasteners prevent galvanic corrosion. Screw length must account for full panel thickness plus purlin penetration.
4. Sealing and Flashing
- Apply butyl sealant tape at end laps and at ridge/eave junctions
- Use matching aluminum flashing at ridge, eaves, gables and penetrations
- Seal all roof penetrations (vents, pipes) with proper boots, not just sealant
Common Site Mistakes
- Walking on panels between purlins (causes denting) – walk over purlin lines only
- Cutting panels with an angle grinder – hot sparks damage the coating; use a nibbler or fine blade
- Leaving swarf (metal filings) on the surface – it rusts and stains the coating
- Skipping butyl tape at laps – the single most common cause of leaks
Request a Quote
GSM BuildTech manufactures and exports insulated aluminum Great Wall roof and wall panels from China to the Middle East and Southeast Asia. Send your area (m²), thickness, and destination port for a 24-hour quote.
WhatsApp: +86 155 2274 6824 | Get a Quote
Related: Great Wall panel specs & pricing · China supplier page · Download spec sheet (PDF)