Visiting the Black Country Museum a few weeks ago, in the rain, I couldn't resist the properly mucky areas of industry. Yes the shops are pretty, but this is an industrial area and so that's the proper history.
This little lean-to workshop is (assuming the museum have got it right) the sort of useful modelling prototype I like. A single story, it's what you make when you've got some bits of a kit left over and don't want to throw them away.
Great for giving a model the "higgledy-piggledy" look that these sort of places developed as buildings were thrown up to do a job, not to look pretty.
Added detail - the ground was compacted dirty stone rather than tarmac. Not very flat, a skim of plaster mixed with black powder paint would do the job. Then add puddles.