I work on a newspaper mailroom nightshift, which is more industrial than it sounds to most people. Lots of machinery.
My first inclination is a pry bar we made out of a drive shaft for an old machine we scrapped for parts, but it's about four feet long, very heavy, and awfully unwieldy. We've got a regular crowbar as well so I might as well just go Gordon Freeman on the zombies.
The building itself would make a fairly decent base of operations, actually. It's located in the middle of downtown and over 130+ years it's absorbed a lot of the buildings around it. A number of the interior walls were exterior walls at some point in time and the doors that went along with those walls were left in place in most cases. So the doors leading into the building are metal/reinforced, then if those were broken down there are multiple "perimeters" within' the building that are just as strong.
We've got a few forklifts that we could use, I suppose...but they're forklifts so they aren't very fast and none of them have a closed cabin.
We also store tons (and tons and tons and tons an-) of paper. Giant rolls of paper that weigh about 1200 pounds each. Two rolls stacked on top of each other is about...six and a half feet tall? And we stack them in columns of a dozen or so. Could easily make a damn near impenetrable wall with those things. Unless a flaming zombie wanders by, which is always possible.