If I saw a building being worked on, there might be "some scaffolding" (uncount.) on it. I wouldn't use "a scaffold" as an alternative. If I wanted to refer more specifically, I would say "the scaffolding on that building." When I think of "a scaffold", the first context that comes to mind is the hangman's scaffold.

I would generally say scaffolding for anything around a building used for construction. And, scaffold for a place where someone is hanged. My cousin is a scaffolder by trade and he and his colleagues all say scaffolding ... if that helps.

Scaffold is the name of the structure, scaffolding is the materials it is made of. However, the difference is often unclear and people frequently use both to mean either. 'Scaffold' has an addition, metaphorical meaning of a structure for supporting any other object. It would be somewhat strange to use 'scaffolding' in this case. If you'd like to use these kinds of distinctions more finely in your everyday speech, maybe book a lesson and we can practise together.

Hi Mikkel. I'm a native English speaker from Australia, and as far as I know there is no US/UK difference here. Wikipedia is wrong – some native English speakers do use the words "scaffold" and "scaffolding" interchangeably, but they're making a mistake. Oxford Dictionary is right – these words do mean different things. The difference is that "scaffold" refers to a completed structure. "Scaffolding" refers to the parts/materials that are used to make that structure. If an analogy helps: if you were building a tower out of lego bricks, then the loose bricks you start with would be the "scaffolding", and the finished tower would be the "scaffold". Example: John built a scaffold by putting pieces of scaffolding together. I hope this helps!