SCB Explains the Block37 Residential Tower

Block37 model inside the SCB offices

Block37 model inside the SCB offices

For the last few months, construction crews have been busy trying to jam an apartment building on top of downtown Chicago’s Block37 mall.  The tower at 25 West Randolph Street is perched on the northern edge of the mall, flush with a very busy street in the heart of the city’s Theater District.  But space constraints weren’t the only challenge that the architects at Solomon Cordwell Buenz had to overcome.  We recently sat down and talked with S.C.B. C.E.O. and friend-of-the-blog John Lahey about the project.

Editor: The Block37 residential tower is a in a very high-profile location. It doesn’t get any more “downtown” than that.  How do you make such a simple design stand out?

Lahey: The thought was this part [the mall] is sort of blocky. But there was also this wavy stuff [on the mall facade] that didn’t seem to have enough presence. We were looking at what to do with this [Randolph Street] wall. It’s almost on the property line, so there’s not much you can do, and then we came up with this idea that you’re always going to see it from the side, and how cool [the waves] would look [from the side], and how it would even make the units bay a little bit.

We really tried to say, “What’s right for this one?”

Block37 Residences drawingEditor: The previous design was an L-shaped building, but this one is a rectangular slab.  What happened there?

Lahey: It came down to the economics of building a new building above an [existing] building, and it was a very difficult project for [the developer] to make work. So we set about figuring out how to make it work, and part of that was a simpler building. They didn’t want a hotel anymore. It’s got 700 units; it’s a big apartment building. The structure is simplified, but you’re going to see it, even though it’s in the forest of buildings in the Loop.  It’s not like The Legacy and people in the park are looking at it. So we took one side and made it work with the office building, and the other side was a long wall.

There was some comment that it’s just a long simple wall, so we had a few ideas, and that one [with the waves] really grabbed people. It’s sort of linked it into the building coming up on the street side and then internally, it was more the sculpture of the rectangular forms.

Editor: So those are people’s units protruding from the facade.

Lahey: Yes. They don’t go out that far. You don’t have to go out very far to get the shadow line, so it was a way of making it a little more eccentric on that north side and enlivening it.

Solomon Cordwell Buenz C.E.O. John Lahey with a model of Block37

Solomon Cordwell Buenz C.E.O. John Lahey with a model of Block37

Editor: Do the protrusions extend beyond the property line?

Lahey: No, because the building at that point is set back a few feet at that point, and that’s what we used.

Editor: 700 units, and the building’s not that tall. Are they all studios?

Lahey: No, there’s a variety of units. But this is meant for people who live and work downtown, and they’re not driving everyplace. Think of the amenities. You’ve got a mall that’s going to have theaters and all that stuff in it. You can have direct access to anywhere from the airport to the pedway. And it’s got a nice outdoor area where you can look out on [Daley] Plaza from the pool. It’ll be a great place to live.

Block37 constructionEditor: We recently published photographs of a giant scary-looking truss on the roof of the mall where your building is going.   Explain that.

Lahey: There’s some columns going down through the shopping, but they eventually end at the loading dock. And there’s columns for the retail, but they can’t hold a whole great big building. The columns at the perimeter, at the edges, they go all the way down, and they’re heavy enough that they can hold a building above.

Editor: Shouldn’t there have been big columns from the start, since the original developer planned to have a big building above?

Lahey: They needed the maneuvering space for the loading docks and the vehicles down below. So the form of the building was really generated by being able to work the structure in a way that was not so expensive that it rendered it undoable.

Editor: Was it always conceived as a flat top?

Lahey: It’s a lower building. It’s not a real tall building in relation to the other buildings around it. Sometimes you see someone try to make the Empire State Building when it’s smaller than all the other buildings around it, it looks kind of silly.

Thanks again to Mr. Lahey for talking with us, and for everyone at Solomon Cordwell Buenz for their hospitality.


Location: 25 East Randolph Street, The Loop

Author: Editor

Editor founded the Chicago Architecture Blog in 2003, after a long career in journalism. He can be reached at

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