Quick Points:

• CarbonCast Insulated Architectural Cladding chosen for LEED Gold enclosure
• Traditional and contemporary aesthetic elements with orange-red brick veneer backdrop
• Precast is simpler than CMU; "just strap between columns and we’re done"
• Cladding solution highlighted in High's Concrete Innovations and Answers® seminar
• CarbonCast façade made under an agreement with AltusGroup, Inc.

Contents:

Summary

  High-visibility LEED Gold project finished with CarbonCast Insulated Architectural Cladding

Sustainable Precast

Thermal and moisture resistance outperforms CMU

Designing Sustainably

Incorporating state-of-the-art solutions

Aesthetics

Architectural system fuses traditional and contemporary design elements

High-visibility LEED Gold project finished with CarbonCast Insulated Architectural Cladding

The $7 million, two-story, 42,000-square-foot Gill Simpson headquarters in Owings Mills, Md., is a showpiece for sustainable design. Blending traditional and contemporary architectural elements, the LEED Gold-designed building represents a new image for a new generation leading the 80-year-old Baltimore-based electrical contracting firm. The build-to-suit project can house up to 80 employees, with 10,000 square feet of adjacent tenant space.

"This was an interesting project," says project architect/project manager Bill Nitzel. "It allowed us to take a different approach than we would have a couple of years ago – the old ‘adorn of the masonry veneer building was about to change," he says. Gill-Simpson owners were determined to use state-of-the-art sustainable materials. When he explained they could have both interior finishes and internal insulation combined with the exterior cladding, Nitzel says "they were excited about such an innovative solution."

"We chose insulated precast walls for the aesthetics, performance, quality control and schedule. Given our winter construction period, with CMU we could have experienced weather delays and the inherent possibility of improper flashing. From a moisture penetration standpoint, 8,000 psi precast concrete is virtually impenetrable," says Nitzel.

Thermal and moisture resistance outperforms CMU

Spandrels and stair walls for the building have an insulation value of R-19 value using a 4" thickness of rigid EPS foam insulation. Wythes of the sandwich panels are joined with C-GRID carbon fiber shear trusses. Column covers are conventional precast concrete with mild reinforcing. Column repetition permitted the use of only precast, without the need to integrate unit masonry or steel lintels.

Another major consideration in choosing the precast architectural system was its simplicity. The design has 24’ spans from column to column. There are no large dimension clear spans in the building. "In the world of unit masonry, this would have meant hanging a lintel to support the window. With precast we just connect between two columns and we’re done," says the architect.

The CarbonCast cladding was cast in an off-white architectural finish with ground granulated blast furnace slag, a recycled material that displaced some of the Portland cement. Exposed precast surfaces received a light sandblast finish. A backup mix of standard structural gray concrete also contained slag.

To the delight of the owner, there is no drywall on the inside of exterior walls of the building. This contributed to the more industrial feel of the interior. Interior corridors were significantly glazed from the floor to the tops of the door heads. The insulated precast walls were supplied with a steel-trowel finish and were painted on site. Nitzel estimates the savings on furring, insulation and drywall alone,at approximately $85,000.

High Concrete Group was contracted directly by the owner in a design-build arrangement, and handled the precast installation.

Incorporating state-of-the-art solutions

Long before the project was conceived, Nitzel and his team attended a High Concrete Innovations and Answers® seminar at High’s Denver, Pa. plant. There they learned about the lightweight, energy efficient precast that became the enclosure for Gill-Simpson. "We wanted the headquarters building to incorporate the latest trends in sustainability and technology," says Nitzel. "The project team was directed toward sustainable design." LEED Gold certification is pending, he says.

This was the first LEED certified building for the design team, and the first precast building for SWB Architects which developed the list of local procurement. The owner was very interested in utilizing a ground source heat pump system. The system delivers a constant 56-58-degreee liquid for heat transfer. The energy cost savings and return on investment were very appealing as "end users of the building.

The building is a steel structure on CIP slab with a metal deck roof system. The project team had considered a "green" roof, but the decision was to make the roof area an energy producer. Solar panels mounted on the roof deliver 75 kW of maintenance-free photovoltaic power for the building’s use. The roof is insulated to R-21 with EPS and covered with white TPO membrane.

Extensive skylights ensure 92% natural daylight, meeting LEED requirements for daylight and views. Rafters, bar joists and the deck underside are visible in the second floor offices and corridors.

Oriented with southern and southeast exposures, the building’s daylighting potentials are supplemented by aluminum interior lightshelves and exterior sun shades The facade of the building is perpendicular to the horizon, with a reverse angled glass entry feature. This alleviates much of the summer time solar loads in the two story entrance atrium. Employee parking is in the rear of the building, along with electric car chargers; the visitor entrance is at the front.

The triangular 13-acre site was formerly used for agriculture and residential uses The building replaces a school bus parking lot, landscape maintenance storage and light retail.

The planned business park is different than the surrounding flex office spaces; tailored to a more discerning occupant, the ideal tenants would be Baltimore based, private firms looking to establish headquarters in an architecturally progressive and environmentally sustainable corporate park. The parcels are visible from 795 North and South, giving it a significant presence on a major interstate.

Architectural system fuses traditional and contemporary design elements

The CarbonCast insulated precast cladding is characterized by traditional columns, light-colored banding and horizontal windows. At the entryway, a contemporary angular glass vestibule on the southeast corner greets visitors. The glass in the vestibule is slightly darker and more reflective than the horizontal windows to defer heat gain. Windows are fixed LOE.

Thin brick was cast directly into the precast panels at High Concrete Group’s Denver, Pa. factory. Raked joints on the brick veneer were extremely important; the joints give shadow lines, depth and texture to the architectural system. The project required its own snap system formliner to ensure the look of the rake joints. The panels featured concrete sill and architectural concrete lintels.

The brick veneer is a standard module orange-red Glen-Gery Tuscan Series Rusty Pink-Modular chosen during the process of choosing precast. The owner saw another SWB-designed building and chose a similar orange brick because of its more contemporary look. The brick color works well with the aluminum window frames and light greenish-blue glass of window system. One interior "feature" wall, which backs the reception area, was also designed to integrate exterior precast elements on the interior of the building. The wall features the company logo.

The use of precast extends to a planter box / wall seat, integrated at the building entrance, and the monument sign for the corporate campus. The owner decided against pervious paving due to the aesthetics and potentially high maintenance. Light color concrete was used for all sidewalks.

CarbonCast is a registered trademark of AltusGroup, Inc.
C-GRID is a registered trademark of Chomarat N.A.
LEED is a registered trademark of US Green Building Council.