What is Galvalume (GL)? Al-Zn Coating Explained
ENSOL Engineering TeamPublished 2026-02-011 min read
Galvalume (GL) is a coil coating of roughly 55% aluminium and 45% zinc (with a little silicon). The aluminium gives excellent barrier corrosion resistance, while the zinc provides sacrificial protection — a balance that makes GL popular for roofing and many mounting structures.
Properties
The aluminium-rich coating forms a tough, adherent oxide barrier, giving long life in many atmospheres at moderate cost. It is lighter and often more economical than heavy hot-dip galvanising.
Where to be careful
GL's sacrificial protection at cut edges is weaker than plain zinc or ZAM, so exposed edges in very aggressive or wet environments need attention. Contact with wet concrete or dissimilar metals should be detailed carefully.