February 2004 marked the beginning of a 7 1⁄2-month-long renovation of the courtyard at the famous Dakota apartment building in New York City. Originally built in 1884 by Architect Henry Hardenbergh, the legendary edifice is a massive, fortress-like structure with a large center courtyard and over 100 apartment units. Manhattan-based architect, John Wender of Bartolone Wender Architects, was chosen to conduct the restoration of the courtyard. He in turn brought James R. Gainfort AIA Consulting Architects on board for masonry and waterproofing expertise. And when work was completed, stone from New York met the design goals and practical challenges.

According to Catherine Paplin, who managed the project in Gainfort's office, the goal of the project was two-fold. “On the one hand, there was the desire to restore the courtyard to its original spirit, and to whatever extent possible, its original materials and look,” said Paplin. “On the other hand, there was simply the desire to make the courtyard beautiful, with a quality of design, workmanship and materials that befit this landmark. The previous gray traffic-bearing waterproof membrane, while reasonably inconspicuous and inoffensive, certainly did not do justice to this space or to the quality and history of the building.”

The architects chose to renovate the courtyard using Glacier Blue[tm] Devonian stone from Devonian Stone of New York, Inc. in Windsor, NY, because of its quality and high level of structural integrity. “We explored different suppliers in New York and Pennsylvania, but they displayed little interest,” said Paplin. “They didn't have the attitude that they were ready to provide a superior product or attentive, intelligent service. [Robert Bellospirito from Devonian Stone] responded differently; quite the opposite actually. He was very enthusiastic right from the beginning, and he emphasized the quality of the stone and the consistency of color. Then he sent us some samples, which we loved. He completely fulfilled all our expectations.”

According to Wender, they knew they were going to use stone all along. “Bluestone was the material that originally formed the sidewalks surrounding the building,” he said. “It was a natural choice. I walked through the job with the client, and when we faced the building, we could see the existing Bluestone to the left and right. I recommended that the courtyard's sidewalks be finished in stone because that is what the original architect placed at the building's exterior. I felt it was best to carry the stone into the courtyard.”

Three months later, Wender and his firm presented their findings to the Building's Board of Directors. After discovering that the underlying steel structure was beginning to deteriorate, and would require a great deal of replacement and reinforcing, they suggested that the original finish material of concrete should be replaced by stone. “I came to this conclusion for two reasons,” said Wender. “The original architect had used monolithic stones slabs at the exterior. Secondly, replacing the concrete would have required pouring a reinforced finish slab of a thickness that would have been prohibitive given the constraints of the project. Stone paving, sized in proportion to the existing Herculean slabs at the portal of the building, would be both more appropriate to the original architecture and technically accomplishable. “

Devonian Stone of New York, Inc. provided about 4,500 square feet of stone for the project -- including paving stone and curbstones -- all flame-finished at the company's fabrication facility in Windsor, NY. Aside from supplying the stone for the Dakota's courtyard, Bellospirito also worked side-by-side with the contractor on the installation process, devising a method using a vacuum-operated jib crane to install each of the heavy stones, which measure from 3 1⁄2 to 6 feet in size. According to the company, “the stone retains a high level of structural integrity, providing cut tolerances of plus or minus 1⁄8 to 1⁄16 inches to the finished product, allowing it to meet the most demanding architectural specifications.”

According to Wender, the size of the stone slabs varies largely due to several factors. “First of all, I wanted to use very large slabs at the driveway to reflect the scale of the enormous slabs at the building's portal,” he explained. “Additionally, because the curb is formed by the stone slab itself, as opposed to a separate curbstone, I wanted the slabs forming the curb to be very large. The slabs then transition back to the perimeter of the building to a more easily manageable scale. The random sizes of the pattern reflect the patterning of the Bluestone on the building's exterior sidewalk.”

“Landmarks required that we make the curbstones around the driveway in the center of the courtyard appear monolithic with the adjacent flagstones,” said Paplin. “We wanted to use an L-shaped piece, but Bobby [Bellospirito] said not to because it would make the piece weak and subject to crack along the points of weakness. Plus, it required more labor to cut into an 'L,' so he told us to just keep it as a slab. What you see is what you get; it's a monumental monolithic 4- x 6-foot x 5-inch-thick piece.”

According to Bellospirito, the pieces that Devonian Stone supplied were typically 2 or 5 inches thick, and they did run into a minor challenge when coordinating the stone at the site. “Space was limited,” he said. “The contractor would send us a list of required pieces on a weekly basis for the following week. We would then fabricate them and get them down to him.” He also experienced some difficulty due to the variety of the size of the pieces, which ranged from 3 x 3 feet to 5 x 8 x 9 inches in the south passageway.

During the mock-up process, the architects faced many challenges in regards to space. “It was difficult getting the entire system to work within the very narrow tolerances we had,” said Paplin. “We only had 10 inches overall to do everything. After considering the paving thickness, the waterproofing and drainage system, a high enough curb and enough slope, we were left with little room for mistakes. It took two or three go-arounds of full-sized section details -- measuring and then measuring again. It was gratifying in the end, and it all dropped into place beautifully. We even had an extra 1⁄8 inch when finished.”

Stokdal Construction Corp. of Kingston, NY, completed the installation of the stone in about 10 months, with 22 workers on the job. According to Kaare Stokdal, the process was heavily involved and required the creation of new space before the stone could be implemented. “We had to remove the existing concrete and substructure, replace the steel, pour the concrete, redo the waterproofing and then install the Devonian stone and granite pavers,” he said. The company used Portland cement and sand mortar, along with Jahn M110 pointing mortar distributed by Cathedral Stone Products, Inc. from Hanover, MD.

In addition to Devonian stone the project also employed granite pavers. “We were going to use hexagon-shaped asphalt pavers like the ones used in Central Park and Riverside Park [in New York], but they were rejected for a combination of reasons,” Paplin explained. “They wouldn't really fit into a courtyard like this.” Instead, the architects chose to use granite pavers supplied by Cold Spring Granite Inc. of Cold Spring, MN.

Wender said that the natural decision was to use cobblestone, but because of the size of the project, this was difficult to do. “We wanted to choose something that looked like Belgium block, so we investigated granite pavers,” he said. “Cold Spring has a good selection and a quality production record.”

According to Wender, the granite pavers are split on some faces, and cut on others. He also said that the granite throughout the main part of the courtyard is 1 1⁄2 inches thick, while the driveway pieces are 4 inches thick and lightly tumbled. “They are split on four sides and sawn on two sides, with a flame-faced finish. We also chose them because they could be installed on a thinner bed,” he explained. “In the course of designing the paving pattern for the granite pavers at the driveway, I designed a herringbone pattern to reflect the guastivino tile ceiling vaults above, and help define the driveway as a special place. Subsequently, I discovered that the herringbone pattern is preferred in driveways because it is tighter and wears better than a stacked or running bond. Installation of the herringbone pattern with 4-inch pavers was very difficult, and the contractor should be commended for the hand sizing of each block that made this possible.”

According to Randy Huber of Cold Spring Granite Inc., the company supplied 3,400 square feet of Iridian granite --quarried in Isle, MN -- in various sizes, including 6 x 9 1⁄2, 6 x 12, 14 x 14 and 3 1⁄2 x 7 1⁄2 inches. “We supplied the material as rectangular pieces,” said Huber. “The contractor cut the perimeter pieces to fit. He also trimmed many of the field pieces in order to maintain exceptionally tight joints.”

An interesting suggestion for the paver installation came from James Gainfort, who suggested that instead of using grout and mortar to set the stone, the crews should use Bluestone dust. “This is a somewhat unusual use of stone dust, but it was very appropriate for the project,” said Paplin.

Wender also implemented stone planters, which he said were not an original element to the building. “I included a stone planter in the presentation of the landmark, and brought to attention that the tenants loved the original planter that was in place, and they agreed to it,” he said. “It is quite massive, and picks up the dimensions of the lantern fountains, which are the original cast iron ones -- an historical element to the courtyard. We put a stone base on the lanterns and restored them. In the past, they were used to light up the basement, but now we use them to light up the courtyard at night to illuminate the Devonian stone and granite. We hid light bulbs inside them, and the light shines out through the windows.”

Great care was taken to maintain a classical look despite the challenges of the site. “We were trying to strive to keep to the spirit of the existing detailing, but had to tweak and invent in order to make the profiles work with the new heights and tolerances, and to replace profiles for which we no longer had direct evidence of the exact design,” said Paplin. “Our overall objective was to create an articulate, coordinated whole that harmonizes the new with the original, and does not deny the present moment -- the fact that this is 2004.”

According to Wender, the tenants are “over the moon with excitement” about the renovation of the courtyard, which concluded this past September.

End box

The Dakota Courtyard Renovation
New York, NY
Architects: Bartolone Wender Architects, New York, NY; James R. Gainfort AIA Consulting Architects, New York, NY
General Contactor/Stone Installer: Stokdal Construction Corp., Kingston, NY
Stone Suppliers: Devonian Stone of New York, Inc., Windsor, NY (Glacier Blue[tm] sandstone); Cold Spring Granite, Inc., Cold Spring, MN (Iridian granite)
Installation Products: Cathedral Stone Products, Inc., Hanover, MD (Jahn M110 pointing mortar)