What Cast Iron Did for a Storefront
Before structural steel, a shopkeeper who wanted a wide, light-flooded ground floor faced a problem: masonry walls need piers, and piers eat the window space that draws customers inside. Cast iron solved it cheaply and elegantly. A slender column — hollow, precisely cast, bolted to a base plate — could carry a brick wall four storeys tall while leaving the entire ground floor open to glass. The technology spread rapidly through American commercial districts in the third quarter of the nineteenth century, and Depot Town got a share of it.
The columns arrived by catalogue. Foundries in Chicago, Detroit and New York published pattern books listing shaft profiles, capital styles and base options, priced by diameter and height. An Ypsilanti merchant or contractor could specify an Ionic capital over a fluted shaft, or a plain Doric cap over something smoother and cheaper, and receive the pieces on the next freight car. Erection was straightforward: the hollow sections stack, pin and bolt, and the whole assembly goes up faster than any mason could lay the equivalent in stone. Speed mattered along a commercial street that was still finding its shape.
What this meant aesthetically was a kind of off-the-shelf classicism — not bespoke, but not cheap-looking either. A cast-iron column carries its proportions well because it was designed by someone who cared about proportions, even if the same design was being bolted up in a dozen other towns that week. Depot Town retains enough original fabric that you can walk the street and see these columns in something close to their intended context: a recessed entry flanked by cast-iron pilasters, a thin cornice above, the upper storeys in brick with corbelling at the parapet. The ground-floor iron and the upper-floor brick are different materials performing different jobs, and the facade reads that way if you look for it.
How to Spot What's Real
The practical test for cast iron versus later replacements is simple. Cast iron rings when you knock it; it shows a smooth surface that takes paint heavily; and the details — egg-and-dart moulding, acanthus leaves, fluted grooves — are crisp and slightly mechanical in a way that hand-carved stone never quite is. A genuine nineteenth-century column will also show its assembly: the base casting, the shaft section, the capital as separate pieces, sometimes with a barely-visible seam where the mould halves met.
Look for the segmental arch above the cast-iron pilasters at the ground level of the older blocks. That shallow, wide arc — not a full semicircle but a flatter curve struck from a longer radius — is the typical transition between the iron framework below and the brick courses above. It distributes the load, and it also signals to anyone who can read it that the wall above is not carrying itself from the ground up: something else is taking the weight.
Condition varies. Paint covers a lot, and some columns have been encased in aluminium cladding during mid-century renovations that were well-intentioned and are now largely regretted. Where the cladding has been stripped, the iron underneath is often in better shape than expected — cast iron corrodes slowly, and if the base has stayed dry it may be nearly as-found. Several Depot Town blocks have had this treatment, and the recovered columns repay attention.
The Thompson Block is the anchor instance: a Civil War-era commercial structure whose surviving fabric still shows the relationship between cast-iron ground-floor elements and the brick above. But it is not the only one. Walk the east side of the street slowly, look at the ground level before you look at the upper floors, and the catalogue logic becomes legible — a set of interchangeable parts, composed into something that still reads as a real place.
Keep reading