Specification of Aluminium Cladding
Material Properties
- Yield strength Min 140 Mpa
- Modules of elasticity 69000 Mpa
- Coeff. of linear thermal expansion 24×10 per deg. C
Durability
Aluminium is highly resistant to corrosion against saline water making it the ideal choice in coastal region for roof cladding.
Fire
Aluminium is classified as a non-combustible material as defined by BS 476:part 4:1970
Mill Finish
This is the natural untreated surface of metal as it leaves the rolling mill.
Stucco-Embossed
Stucco-embossed aluminium is mill finished aluminium. This is roller embossed to produce irregular male female pattern finish. The advantage of embossing is that direct reflections and sun glaze are diffused, without reduction in the total reflectivity.
Polyester Colour Coated
An economical, long-life coated, factory applied polyester on the exposed side, and a lacquer coating on the reverse side.
PVDF Colour Coated
Excellent U.V resistant, long-life coating of 2 coats of factory applied PVDF on the exposed side and a lacquer coating on the reverse side.
Base Material
The base material shall conform to ASTM A 653 or other equivalent standards like JIS 3302, EN 10326/10327 and IS 277.
PPGI – Zinc Coating (Galvanized)
The base steel material is hot dipped galvanized Zinc coated as per ASTM standard with a coating thickness range 180gm/m2 to 270gm subject to confirmation at the time of placing the order.
PPGL – Galvalum (Alu-Zinc)
- The Alu-Zinc coating has unique micro-structure.
- Alloy layer forms at the interface between the coating and steel substrate.
- Overlay coating has two main phases — Aluminium rich dendritic phase & Zinc rich interdendritic phase.
Corrosion Resistance Mechanism of Alu-Zinc
- When Alu-Zinc sheet is exposed to environmental conditions, the rich interdendritic portion of the coating corrodes preferentially.
- Coating is sacrificial to steel and serves galvanically to protect the steel substrate.
- As Zn rich portion of the coating is gradually corroded, the interdendritic interstices are filled with Zn corrosion products.
- The above mechanism in Alu-Zinc material results in barrier protection & Galvanic corrosion protection.
Superior Corrosion Resistance of Alu-Zinc
The combined action of Aluminium and Zinc makes Alu-Zinc more effective than steel coated with pure zinc.
Paint Coating (For Aluminium and Steel)
Paint applied on top of galvanized/Alu-Zinc/Aluminium material in a continuous (Coil) coating process.
Polyester (RMP)
An economical long life coating. External side coated with 20-25 Microns polyester paint and internal side with 6-10 micron epoxy primer.
PVDF
This coating has high resistance to alkaline atmosphere and excellent UV resistance compared to polyester coating. Coating thickness 20-25 Microns on external side and internal side with 5-7 micron epoxy primer.
Method of Installation
First tighten the sheet with screws then fix the self locking caps, by pressing on top of the ribs making it 100% water proof. It can be laid with z purlins or box purlins.
Aluzinc
Thickness 0.4mm to 0.9mm. Yield strength 340 MPA and coated with an alloy of aluminium and zinc (Aluzinc) with a minimum alloy coating of 150grams per sq.m. Top coating is of minimum 20 microns, available in PVDF and RMP, in different colors. Bottom is coated with 8 microns.
Aluminium
Thickness 0.6mm to 0.9mm. Yield strength min 140MPA. Top coating minimum 20 microns available in PVDF, HD and RMP in 5 different colours. Bottom coat is minimum 8 microns.