I've always called it "my shed" - this began as a running joke because it was actually a 4000sq/ft warehouse....
An Englishman's "shed" is where he goes to Invent Things, and Make Things (not necessarily the same Things, because many sheds lack the facilities to make the sort of Things that Englishmen like to invent in their spare time).
A shed is also a valuable WFZ (Wife-Free Zone), where things that get put down (e.g. tools, interesting pieces of metal, wood or rock) stay where they are put until they are next needed. Unlike the Kitchen - where any item put down for later use will invariably disappear from said place in a time inversely proportional to teatime.
Real Men know that nothing is really STORED in sheds (this is what lean-tos and garages are for), everything in a shed is merely "en route" to the next time it might be needed. That this can, in some cases, mean an item not moving for many years, even decades, in no way implies it is being "stored" there.
An actual garden shed, unless new, MUST look like it's about to collapse under its own weight, despite the fact it's actually probably very sturdy... Modern sheds, of course, are ideally internet-connected and quite possibly have their own wi-fi hot-spot; not to mention a paraffin-fired hot-spot near the Inventing Area.
