Galvalume Prepainted Steel Coil UV Stable RAL Curtain Wall Panels

Galvalume Prepainted Steel Coil UV Stable RAL Curtain Wall Panels

Curtain wall panels are viewed at eye level and at an angle, which is the least forgiving way to look at coated steel. Any flatness deviation, gloss inconsistency or shade step becomes obvious. This Galvalume prepainted coil is specified for that application: the substrate is levelled before coating, the color is matched inside the RAL system, and the UV stable top coat is selected so the facade keeps its intended tone rather than drifting over the first five summers.

Galvalume, a zinc aluminium alloy coating, also gives the panel maker more corrosion margin at the folded edges and concealed fixings that curtain wall systems rely on.

Parameters

Advantages at Eye Level

• Levelled substrate reduces the oil canning effect that ruins flat facade panels.
• Controlled gloss avoids harsh reflections from adjacent buildings.
• UV stable coating keeps the shade consistent across a large visible surface.
• Aluzinc substrate protects folded cassette edges and concealed fixings.
• Batch color data supplied for architect approval and site inspection.

Curtain Wall Applications

• Cassette and tray panel facade systems
• Rainscreen cladding with concealed fixings
• Commercial office and retail facades
• Canopies and architectural feature panels

Questions from Facade Contractors

How do you control oil canning?

Two things: levelled substrate with a measured wave height limit, and a gloss range that does not amplify reflections. We also advise the panel maker on stiffener spacing, since panel design contributes as much as the coil.

Which thickness suits cassette panels?

Most cassette systems run between 0.7 and 1.0 mm. Thicker gauges resist oil canning better but increase weight and cost, so the system supplier usually sets the figure.

Can you supply matched samples for architect approval?

Yes, we issue A4 coated samples with batch reference and measured color data before bulk production.

Is the coating suitable for coastal facades?

Yes with the AZ150 substrate and a 25 micron top coat. For severe marine exposure we recommend a higher build coating and a shorter inspection interval.

Packing

Coils ship eye to sky with PVC film, paper interleaving and steel strapping on wooden pallets, labelled with heat number, coating batch and flatness reading. Panel makers running automated lines should confirm mandrel diameter so we can set the coil eye and wrap tension for smooth decoiling.

Coordination with the Facade System

Coil performance is only half of a successful curtain wall. Panel flatness also depends on stiffener spacing, fixing pattern and the temperature at installation, so we ask for the system drawing and the expected panel size before confirming the gauge. Where a project has a mock up requirement we supply material from the production batch that will be used for the actual facade, so the approved mock up and the delivered panels come from the same coating run rather than two different ones.

The substrate is Galvalume steel AZ100 - AZ150, levelled. The AZ designation describes the aluminium-zinc alloy coating weight, which is what gives cut edges and drilled holes their sacrificial protection. A higher coating weight extends time to red rust, but it also changes forming behaviour, so the grade should be matched to the exposure class of the finished building.

Coating thickness matters more than coating brand in service: Top 22 - 25 micron, primer 5 micron. Below roughly 20 micron total build, UV exposure in strong sun starts to chalk the surface within a few years, and the colour drifts before the steel itself shows any problem.

Formability is specified as T bend 2T for cassette folding. This determines whether the strip can be roll formed and folded at the job site without cracking the coating over the bend radius, which is the most common cause of premature coating failure on roofing panels.