Wedge sole. Lugged sole. The two dominant work-boot sole patterns and they exist for different reasons. Buying the wrong one because you liked the look is a common mistake.
A wedge sole is a flat-bottomed sole, usually crepe rubber, that runs from heel to toe in one continuous angle. No deep tread. The whole bottom of the boot is in contact with the ground. The Thorogood American Heritage moc-toe is the canonical example. So is most of the older Red Wing line.
Wedge soles are made for hard, flat surfaces — concrete, finished wood, hardware-store floors, factory floors, scaffolding planks. They distribute weight across a larger contact area, which means less foot fatigue across a long day on a slab. They don't track mud and dirt into the building because they don't have deep treads to hold the dirt in.
Wedges are bad on soft ground. They slide on grass. They sink in mud. On a wet hill, they're outright dangerous. If you stepped onto a roofing site in wedges, you'd have a story to tell.
"Wedges on a roof is a story you don't want to tell."
A lugged sole — Vibram is the dominant brand, but plenty of in-house tread patterns qualify — has deep, defined treads that bite into soft surfaces. The contact patch is smaller because only the lugs touch the ground, but each lug grips. Lugs are made for dirt, gravel, mud, snow, uneven terrain, ladder rungs.
Lugs are worse on hard flat floors. The smaller contact patch means more pressure on a smaller area, which means sooner fatigue. Lugs also track mud everywhere — every divot in the tread is a small reservoir for whatever you walked through.
Trade-by-trade rough cut: indoor electrician, indoor plumber, factory work, retail trades — wedge. Outdoor framing, roofing, excavation, tree work, landscaping, mixed-terrain work — lugged. General contractor with both indoor and outdoor work — lugged is the safer pick because the cost of slipping outside is higher than the cost of fatigue inside.
Hybrid tread patterns exist — a shallow lug that splits the difference. They compromise both directions. Sometimes that's exactly what you want.