Difference Between Galvanized and Galvalume Steel
Galvanized steel and galvalume steel are widely used in our daily life for roofs and wall panels, etc. Both have strong corrosion resistance and smooth and shiny surface. So what’s the difference between them and which one is better for your projects?
- Coating: The main difference between galvalume and galvanized steel is the protective coating. Galvanized steel is coated with pure zinc coating. While galvalume has a Al-Zn coating, that is 55% aluminium, 43.4% zinc, and 1.6% silicone. The aluminium in the galvalume coating helps to better protect the panels against corrosion in certain environments.
- Appearance: Galvalume steel is generally considered to have a better appearance when compared to galvanized steel. The two coatings’ differences are subtle, but galvalume offers a smoother appearance with 'spangles', and its base colour is silver-white. A galvanized coating is more rough.
- Corrosion resistance: Based on their substrates, the special coating structure of galvalume makes it more resistant to corrosion than galvanized. Generally, the corrosion resistance of galvalume steel is 6 to 8 times that of galvanized steel, especially in acid rain. It can guarantee no rust for 20 years.
- Atmospheric corrosion resistance: In the harsh marine environment, rural and industrial environment, the corrosion resistance of galvalume steel is better than that of galvanized steel.
- Adaptability to humidity: the Cleveland condensation experiment shows that the humidity and corrosion resistance of galvalume steel sheet is 5-6 times better than that of galvanized steel sheet.
- Heat resistance: The heat resistance of galvalume steel is better than that of galvanized steel. The galvalume steel sheet can withstand a temperature of 677 , and often works at 315 without discolouration.
- Generally, cold galvanized steel can last 5-10 years and hot-dipped galvanized steel sheet has a lifespan of 20-30 years, mainly depending on the zinc layer thickness. The base steel will be damaged as the zinc layer is all corroded. But due to aluminium’s excellent prevention of corrosion, the galvalume steel has a lifespan about twice that of traditional galvanized steel.
- Applications: Galvalume is ideal for humid and hot environments, commercial buildings, residential homes, storage units, and more. Galvanized metal is better suited to dry climates free of major air pollution or pooling water. The aluminum in galvalume will corrode with exposure to alkalines, which can cause the metal to degrade and lose its strength.
- Price: Due to better performance and fewer qualified manufacturers, galvalume steel price has a higher than that of galvanized metal.
[edit] Related articles on Designing Buildings
Featured articles and news
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
BSRIA Occupant Wellbeing survey BOW
Occupant satisfaction and wellbeing tool inc. physical environment, indoor facilities, functionality and accessibility.