An extra foot of roof. Sounds minor, changes everything — if someone is going to stand up and work in it, or you're stacking pallets of seed and fertiliser two high, buy the high cube and don't think about it again.
Two reasons, and only one of them is headroom. The obvious one: if a person is going to stand up and work in it, 2.69m is the difference between a usable space and a stoop. That's why nearly every workshop conversion and site office we supply is a high cube.
The second one is air. The Downs runs a big swing between a hot afternoon and a cold clear night, and sealed steel condenses on the inside of the roof as it cools — people mistake it for a leak every year. The extra height gives you room to fit vents high on both ends so air crosses the space instead of sitting in it. There's more on that in the Toowoomba buyer's guide.
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