*Sandwich Panel = Sandwich Panel Sheets* used for building annexes, warehouses, and prefabricated rooms. *Specifications and Installation of Sandwich Panels for Annexes* *1. Installation - 3 Layers* Sandwich panels consist of two metal layers with insulation in between: 1. *Outer Layer*: Coated galvanized steel - Thickness: 0.4mm to 0.6mm - Resistant to rust, heat, and sunlight 2. *Insulation Layer in the Middle*: - *Polyurethane PUR*: Excellent thermal insulation. Density 40 kg/m3. This is the most common for annexes. - *Rock Wool*: Thermal insulation + Sound insulation + Fire resistant - *Polystyrene EPS*: Cheaper but less insulation - Thickness: 4cm, 5cm, 10cm as per your needs 3. *Inner Layer*: Coated galvanized steel - Thickness: 0.4mm - Usually white inside for better lighting *2. Common Sizes for Annexes* - *Width*: 1 meter (standard in most factories) - *Length*: Upon request, from 2 meters to 12 meters - *Total Panel Thickness*: 4cm for internal partitions, 5cm for external walls, 10cm for the roof if the weather is hot *3. Benefits for Annexes* - *Fast Installation*: Panels are installed with self-tapping screws on the same day - *Thermal Insulation*: Makes a big difference in Riyadh's heat. 5cm PUR reduces heat by 70% - *Lightweight*: Does not require strong concrete foundations - *Moisture and Rust Resistant* if the steel is galvanized *4. Approximate Price in Saudi Arabia 2026* (Varies by thickness and color) - *4cm PUR*: - *5cm PUR*: - *10cm Roof*: The price includes the panel only. Installation, screws, and angles are separate. *Tips for Building an Annex* 1. *For External Walls*: Use 5cm PUR 2. *For the Roof*: Use 10cm for sun protection 3. *For Internal Partitions*: Use 4cm rock wool if you want sound insulation 4. Ensure the steel is *G275 galvanized* to prevent rust Do you want an annex, a room, a warehouse, or a shop? Tell me the dimensions you have in mind, and I'll calculate the number of panels you need and the approximate cost.