Nice camp chair!
Those roofs look like they're working as desired.
Not that it's a likely option in that area, but anything built for human occupation here in the urban part of the Lower Left Coast now has to have a fire sprinkler system in it. Even single family dwellings. I'll assume this is true for some other regions, but I have no knowledge of that.
I've always worried more about some of the, ah, 'fragrances' found in a shop permeating the home if it were built above the shop. Like the old fashioned, real carburetor cleaner that you can't get any more. Or old, used gear lube. Or Epoxy paints and resins. Or......
A friend and I were discussing his place in WY where it can get quite cold. One of the issues his property has is that there is no where to move the snow berm that the plows push up across his driveway. He is considering a heated driveway to offset this. I realized that "heated" could be relative. With a deep enough sump I would expect that water in that sump would be well above freezing temperature without having to actually heat it. Merely pumping it thru his driveway could slowly melt any snow or ice on the driveway. There's lots to consider with this plan, but it got me to wondering about if you could passively heat a home or shop this way. I've no idea how deep you'd need to go, or what the water volume would need to be for the system to be effective.