The $74 million renovation of the 28-story former Montgomery Ward & Co. office building brought with it possibilities and problems - and new curtain wall.

The Ward retail chain, which announced its closing in December 2000 after 128 years in business, left behind an architecturally distinctive tower in Chicago's River North area.

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Nancy Carreon, director of construction for Chicago-based Centrum Properties Inc., a member of the MW-CPAG Tower Holdings LLC development team on the renovation, said a unique feature of the structure, which was originally built in 1972, is the absence of perimeter columns along the prominent north and south facades.

The original design of Minoru Yamasaki, the same architect of the destroyed World Trade Center Towers in New York, called for columns within the Ward building to carry cantilevers of about 20 ft. along each 165-ft.-wide facade.

Floor-to-ceiling windows were the result, and they provide phenomenal views of Chicago's beautiful skyline and surrounding areas.

The hook of extraordinary views throughout made the building ideal for redevelopment as a 247-unit condominium called The Montgomery.

"This is unusual for any condo building: The height of the vision area on each floor is 9 ft., 6 in. tall," added Tom Niepokoj, president of Bolingbrook, Ill.-based Architectural Wall Solutions Inc., the curtain wall contractor on the renovation.

Looked at from the outside, however, the original curtain wall presented a different view.

Carreon said the famous dark bronze color of the aluminum and glass curtain walls between the four limestone edges were showing wear and looked "very oppressive" - elements not likely to help generate sales of units with asking prices between $325,000 and $1.9 million.

Moreover, the original curtain wall represented dated technology.

No windows could be opened. Niepokoj added, "The water and air infiltration standards of the existing curtain wall were pretty archaic."

A retrofit was considered, but the cost and lack of supplier warranty precluded it.

At the same time a fresh look and current standards were sought, and the decision was made to strip the old curtain wall system - the main facades and the slivers on the east and west - and install a new one. It is hoped the new curtain wall will provide a revitalized appearance and top performance.

Old and New Facades

Careful planning was required to demolish the old curtain wall and install the replacement.

Demolition began in January. The floors had to be gutted before the curtain wall was removed so that the hazard of materials blown by the wind could be avoided, said Bill Griffiths, vice president and senior project manager of Chicago-based Linn-Mathes Inc., the general contractor.

Small Bobcats and manual labor were used to remove the mostly lightweight materials, including office partitions, carpeting and light fixtures. Not all removals were so easy because the boilers and chillers on the 27th level, the former mechanical floor, were big.

Fortunately, a freight elevator with 10,000 lbs. of capacity was in good shape to take down most materials, Griffiths said. Using the lift also avoided the cost of a hoist.

In May most floors could be seen through entirely.

"It was a deck of cards stacked," Carreon added.

Because the replacement curtain wall is stacked, the existing one was removed from the bottom up and floor-by-floor.

As the old curtain wall was removed on the upper levels, the frames for the replacement were installed below to save time. Outrigger beams perpendicular to the building face were installed on the 14th floor, and netting was strung between the arms to ensure debris was caught.

The curtain wall removal was done from the inside, Carreon said. Glass cutters were used to remove pieces, and the vertical mullions and horizontal spandrels were also taken out.

About a day was needed to clear a floor of curtain wall. The steel imbeds, which anchored the existing curtain wall to the structure, were the only components retained.

A portable crane was installed inside on two levels to hoist new materials outside the building to each floor, Griffiths said. Once they were ready, the framing, glazing and vents were set into the structure on each floor from within.

The 28th floor, which originally was only partly constructed, was filled out in full so that concrete skeletal structure was available for crews to anchor the new curtain wall to.

The blue-green-tinted replacement glazing with clear anodized framing will have the bells and whistles of current curtain wall technology.

Each vision panel with have an operable window for a total of 1,660 vents in the building. The low-emissivity glass has metallic coatings that reduce heat loss in the winter and heat gain in the summer.

A 30-ft.-wide, 16-ft.-tall mock-up was built at Construction Research Laboratory Inc. in Miami for tests to ensure the curtain wall met the criteria for air and water infiltration and thermal performance, Niepokoj said. The system passed, and 122,000 sq. ft. of aluminum and glass curtain wall form the facades.

Unexpected situations were occasionally encountered.

"Floor-to-floor heights in locations varied by as much as 4 in.," Niepokoj said. The detailing was adjusted to accommodate these variances.

Glazing started in April and is expected to be finished in mid-August.

Montgomery Monitor

One-, two- and three-bedroom units will be offered, and the first occupancies are expected in spring 2005.

Floors two through five will hold 259 parking spaces, and a circular and enclosed ramp will be constructed on the east to provide vehicle access.

Tower amenities include a dry cleaner, spa and restaurant on the first floor, and fitness center, rooftop terrace and individual terraces for the upper-floor condominiums.

A design issue was deciding what to put in the building's solid limestone corners, which were used for toilets, electrical closets and service elevators when Ward occupied the building.

Finding good uses for spaces without windows was key, and bathrooms, laundry rooms and family rooms were placed there, Carreon said.

"You don't want [those spaces] to be bright as a living room or bedroom," she added.

Servicing a High-Rise

Planning was key to updating the building's mechanical, electrical and plumbing system for residential use.

Key issues included moving the mechanical room from the 27th floor to the garage's southern portion and converting piping that was previously centralized for residential application.

A four-pipe fan coil system for heating and cooling is being installed, and eight to 10 cores are required per unit per floor, Linn-Mathes' Griffiths said. Because there are 12 to 13 units on each floor, that translates into 100 to 200 saw cuts per floor.

Coring precision was required because rather than a flat slab, a floor-joist system was originally installed. Care was needed to avoid going through the between-floor joist beams.

Vertical chases were installed, Carreon said. Because the building was previously used as an office, there were 13 elevators - excessive for a residential high-rise.
Seven were removed and filled in.

One shuttle is to be extended two levels so it services the penthouses. The motors and controllers were moved up during the surgical demolition of the former mechanical room.

"There is some tricky demolition in the northwest corner of the building," Griffiths added. "Part of the elevator equipment is staying in its present location while we do structural demolition and raise very large machines up to the new penthouse level."

Drywall framing was expected to begin in June.