900-910 North Lake Shore vs Promontory Apartments

Comparing the 900-910 North Lake Shore and the Promontory Apartments is particularly interesting because they share the same skyline in Chicago, IL, and were both designed by Mies van der Rohe. However, they were completed more than 7 years apart.

This offers a unique perspective on how the architect's style and the city's architecture evolved over time.

These two towers present an interesting contrast in their proportions. The Promontory Apartments rises higher at 218ft (66.5m), while the 900-910 North Lake Shore reaches 0ft (m). However, the 900-910 North Lake Shore accommodates more floors with 29 levels above ground, compared to 22 floors in the Promontory Apartments.

This suggests different approaches to interior space design. The Promontory Apartments has an average floor-to-floor height of approximately 3m, while the 900-910 North Lake Shore has more compact floors averaging around 0m each. The taller building's more generous floor heights might indicate grander interior spaces, higher ceilings, or different programmatic requirements.

These different proportions likely reflect the specific needs each building was designed to serve, whether driven by zoning regulations, client requirements, or the intended use of the spaces within. The contrast shows how architects can achieve different spatial experiences even when working with similar overall building scales.

Both the 900-910 North Lake Shore and the Promontory Apartments were designed in line with the aesthetic conventions of the International Style style.

At the time, this style was at the height of its popularity. So Mies van der Rohe followed what was in many ways expected at the time, producing designs that fit comfortably within contemporary architectural norms rather, than breaking with convention.

Both the 900-910 North Lake Shore and the Promontory Apartments were designed to serve as residential towers, and that has remained their main use since their completion, serving similar roles in the urban fabric.

In terms of capacity, the 900-910 North Lake Shore offers 524 apartments, while the Promontory Apartments provides 122 units.

Both towers share the same structural solution, a Frame system.

A frame structure uses a grid of columns and beams to carry the building's loads. This frees the walls from structural duties, allowing for flexible floor plans and larger windows.

However, when it comes to the facade, both buildings use different approaches. The 900-910 North Lake Shore uses a Curtain Wall facade, while the Promontory Apartments uses a Window Wall facade.

A Curtain Wall facade like the one seen in the 900-910 North Lake Shore uses a lightweight glass curtain wall hung from the structure, while a window-wall facade like the one seen in the Promontory Apartments uses panels fitted between floor slabs, leaving slab edges visible.