Slab, corridorSlab, double-loaded
937 Glisan
Holst Architecture/Ankrom Moisan | Portland, USA | 2007-9
Image of 937 Glisan
View from the Northwest

Project937 Glisan
ArchitectHolst Architecture/Ankrom Moisan
Address937 NS Glisan Street
Building TypeSlab, double-loaded
Number of Dwellings114
Date Built2007-9
Dwelling Types1, 2, & 3 BR
No. Floors16
Section Typeflats
Exterior Finish
brick, metal windows
Construction Typeconc. frame
Ancillary Servicesground floor retail, parking garage

937 Glisan is a 16-story slab built along one side of a block in the heart of the Pearl District adjacent to Portland’s central business district. The “Pearl” was an area of mixed light industry, warehousing, and rail yards extending along the Willamette River north of the downtown area. Over time, the change in commercial shipping, the demolition of old buildings, and the removal of an elevated viaduct resulted in a pattern of old buildings, scattered open space, and an abandoned rail yard. In the 1990’s the City made the decision to develop the Pearl as a new residential and commercial district. The name “pearl” seems to have been a reference to the precious contents of the art galleries that came to occupy these old buildings during this period. The new plan involved the conversion of existing historic buildings such as the Weinhard Brewery, for example, that had been in use since 1864, as well as the construction of several thousand new apartments, mixed commercial and retail, and the creation of new public parks including the northern extension of a zone of historic park blocks that were an important feature of central Portland. An important part of the Pearl concept was the construction of a streetcar line connecting the Pearl to other landmarks to the south including Portland State University and an aerial tram connection to the Oregon Health Services Campus overlooking the Ross Island Bridge.

937 Gilsan is an example of a strategy for developing one of the typical 200’ x 200’ Portland blocks. Building uses and heights are limited in the Pearl District by a Floor Area Ratio of 5:1 (FAR: the ratio between building and site areas), by the requirement of ground floor retail and commercial uses, parking requirements, and a complex formula whereby air rights can be negotiated to achieve FAR’s of up to 9:1. This results in the 16-story height of 937 Glisan, the slab form along the south side of the block and the extended commercial plinth at the ground floor.

The high-rise, double-loaded slab has been the dominant urban residential building type for both luxury and low-income housing in the US. for the past 60 years. The multiple exit requirements of national fire codes coupled with the inherent efficiencies of an internal corridor system render this type of building the preferred instrument of exclusive residential developments such as Mies van der Rohe’s 860 Lake Shore Drive apartments in Chicago, for example, as well as the means of achieving the high densities required of most speculative high-rise housing and most lower income “project” housing in American cities.

Derived from 1920’s zeilenbau precedents, the open space requirements of the double-loaded system make this less suitable as a building type for use in most typical perimeter block situations. The clear logic of the floor plans of Miesian slab precedents was the result of fire exit requirements and building codes that allowed windowless kitchens and baths so that services could be concentrated in a zone along the central corridor. In this arrangement all living spaces could be organized in a deeper zone around the outside of the building. The difference between luxury and low-income applications was reduced to issues of location, dwelling size, materials and equipment, and extra amenities such as balconies and terraces, swimming pools, and other common spaces of various kinds. The typical one-bedroom apartments in 860 Lake Shore Drive (26 floors) have a spectacular lakeside location but the apartments are actually quite small. In less exclusive locations such as Lafayette Park in Detroit (Mies van der Rohe, 1956, 21 floors), for example, or Lake Meadows in Chicago (Skidmore Owings & Merrill, 1961, 21 floors), the slab form is extended to the code limits for corridor lengths. 937 Glisan at 16 floors, with a length of less than 200‘, is a scaled-down version of the narrow slab type and shares a very similar organizational DNA with these examples.

Building on the small Portland blocks tends to result in the design of two distinct building types. First, the whole block could be covered with a single building. The Marshall-Wells Hardware Company Warehouse No. 2, designed by Daniel Burnham in 1910 and later converted to housing in 2002 by Ankrom Moisan is an example of this type; 6-stories high, covering the entire block. The second, more typical model was a pattern of buildings on smaller parcels at the corners or along the perimeter of the block. These buildings varied in height from one to 4 or 5 floors and were built at different times in various styles with different materials. The resulting urban fabric is a varied texture of building and open space frequently involving vacant lots or open space on the interior of the block. Because of the small size of the block and the fact that the existing buildings were not residential, the interior open space typical of most perimeter block land use patterns seldom occurred in Portland. The conversion of the large blocks to housing was made by removing of the center part of the building creating a rather small, shared courtyard that provides day lighting for the apartments on the courtyard side of the corridor. Marshall-Wells is an example of this type. The creation of the courtyard changes the FAR formula for the building and usually a couple of floors have been added to the top of the building resulting in a very abbreviated version of a perimeter block where a double-loaded corridor system has been wrapped around the central open space that has, in this case, been rotated 45 degrees.

At first glance, 937 Glisan appears to be a 16-story slab, a block long aligned on an East/West axis along the south side of a 200 x 200 block. A closer look, however, reveals that the building functions are expressed as a commercial plinth that covers the south half of the block and supports a 15-story residential slab aligned along Glisan. The slab is flush with the plinth along Glissan but steps back about at the ends in response to FAR limits. The plinth provides a zone of storefronts along the street, the building lobby as well as the parking entrance and access to a 40-foot wide service zone continuously along the north side of the parcel. The plinth is expressed as a zone of aluminum storefront glazing, 11 feet in height that is visually detached from the slab above by a continuous, slightly recessed zone of glass.

The tower is rendered in brick and glass. The light-colored brick provides an economical exterior material. The windows are all the same height but vary in width and function and are recessed from the outer brick surface implying an “infill” condition in a structural frame. They form a “kit of parts” that is applied in response to interior needs and over all façade organization. Because the columns set back a few feet from the outer wall, the vertical zones of brick are aligned independently of the columns while the horizontal bands align with the position of the floor structure. The repetitive misalignment of the vertical elements from floor to floor and the uncertainty of exactly what is structural results in an intriguing, diaphanous ambiguity about the façade; is it simultaneously transparent and opaque; is it both structure and skin? An economical skin has been designed that is hierarchical and architecturally interesting but avoids the monotonous repetition typical of most housing.

One of the most striking features of the tower is the use of several vertical groups of partially recessed balconies that are colored a deep purple (it has been suggested that this is the color of Oregon Pinot Noir). These balcony elements, several floors high, create deep niches in the otherwise flush exterior wall and provide dynamic three-dimensional interruptions to the repetitive exterior. These balconies are recessed into but also cantilever forward a few feet from the façade. All the materials used in the balconies except the aluminum glazing are purple including the glass in the balustrades and the wall surfaces that line the recessed surfaces of the balconies. A second type of balcony is used sparingly in a stepped pattern on the north façade. These balconies recall pure modernist precedents and are a cantilever type with clear glass balustrades offering spectacular but slightly vertiginous views from the upper floors. Larger terraces occupy the corners of the large dwellings on the top two floors on the south side. These elements suggest a cornice condition, however a developed roof is missing from the program.

937 Glisan contains 114 one, two, and 3-bedroom apartments that range in size from 634 square feet to almost 1600 sq. ft. for the largest dwellings on the top floors. The floor plans closely model other US double-loaded corridor Miesian precedents such as 860 Lake Shore Drive, Lafayette Park and other similar examples like I.M.Pei Kips Bay, Lake Meadows in Chicago by SOM, and other projects. These examples have a similar plan organization with a central corridor connecting fire stairs and elevators and a zone of apartment entrances, kitchens and baths arranged in a zone along the corridor. These buildings vary widely in their proportions, structural systems, and materials, and the building regulations and limitations under which they were built and the plans are quite similar. The slab proportions of these examples vary, as do the structural bays. Mies preferred a 20’ structural bay, Lafayette Park in Detroit, for example, while 937 uses a 30’ structural bay (4 as compared to 3 bays). Lafayette, of course was built under FHA limitations so the apartments are smaller. A 2-bedroom, 2-bath apartment from 937 is close to the size of two, one bedroom dwellings from Lafayette.

In 937, the kitchen, dining, and living functions are combined in one long, narrow room that is modulated by the columns that stand just inside the outer wall. This results in very generous, well-lighted spaces looking out over the city. Some of the 2 BR dwellings at the corners and one-bedroom apartments along the sides, have window-less interior bedrooms. While this is allowed under the new IBC rules, it seems like a curious loss of amenity for expensive housing like this. A perennial problem with the double-loaded slab as a housing type is orientation. The south-facing apartments along Glisan enjoy the best possible siting, with some southern terraces and beautiful views of the city. The north-facing apartments and especially those on the lower floors are looking out over the 40’ wide roof of the retail plinth. The similar wall treatment of all four facades seem to belie the traditional North/South alignment of most housing precedents. Although this roof area is partially landscaped, new buildings could be built close to the lot line at some time in the future. Even with these limitations, however, 937 is a provocative application of a modernist building type being used as a key building element in a perimeter block situation. It is certainly one of the most interesting new buildings in the Pearl.

King, Bart, An Architecture Guidebook to Portland, Oregon State University Press, Corvallis, 2007, p. 169

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