https://www.honeycombpanels.eu/en/products/sandwich-panels/floor/compocel-floor-aluris-compocel-floor-aluman
honeycomb
Obvs., but I looked a couple of months ago and it's hard work getting small quantities at anything like a reasonable price. In this lightly loaded and well supported application, there's no real advantage over solid aluminium treadplate.
@JurekB started
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https://www.honeycombpanels.eu/en/products/sandwich-panels/floor/compocel-floor-aluris-compocel-floor-aluman