Kevin Daly Architects and Houston Endowment net-zero from PRODUCTORA
Kevin Daly Associates (kdA) and PRODUCTORA designed a new headquarters for the Houston Endowment with consideration for the region’s humid climate. When completed, it will feature a facade of scalloped vertical panels punctuated with windows. Following a competitive process, the new headquarters of one of the city’s most prominent philanthropic organizations was awarded to kdA and PRODUCTORA in November 2019 over shortlisted competitors Deborah Berke Partners, Olson Kundig and SCHAUM/ SHIEH. Located in Spotts Park, the 25,000 square foot building will include offices, conference rooms and multi-purpose event spaces.
The design team predicts net zero energy performance. The building’s frame is constructed of steel and cross-laminated timber (CLT) to allow for interior flexibility. Reminiscent of the original Menil Collection building designed by Renzo Piano Building Workshop, a prominent canopy spans the structure to reduce solar heat gain while providing shade for outdoor terraces. Indoors, ceiling fans will lower noticeable temperatures while reducing the mechanical cooling load. The clerestory windows will open the center of the interior to natural sunlight. To further reduce energy consumption, the partially underground parking lot will be naturally ventilated.
Energy consumption will be further conserved through a closed-loop geothermal system. Natural ventilation was considered early in the design phase, but given Houston’s fluctuating humidity levels, the energy cost of constantly switching between cooling modes would not be offset by the energy savings of running times. where the weather would permit natural ventilation.
The building will rise two stories, with the canopy ladder being the most visible when viewed from the east and west faces of the building. The ground floor plan protrudes more than that of the second floor, allowing for the second floor terraces above. The undulations of the aluminum panels add a geometric complexity to the facade that otherwise would not be apparent if the building had been designed with flat materials. The continuous series of aluminum panels that envelop the facade will only be interrupted, at least from an exterior view on the north and south faces of the building, by the columns supporting the canopy. KdA, PRODUCTORA, Transsolar and CMTA addressed performance needs from the earliest stages of the design process. The team sought daylight from “multiple orientations”, while trying to reduce solar heat gain.
It was also important to preserve the view of the park “for all occupants”, although a fully glazed building would not have been compatible with the net zero objective. A collaborative design process produced a “program-appropriate pacing for the openings,” said kdA partner Luke Smith. Transsolar conducted heat gain and daylighting analyzes during the design process.
After exploring terra cotta, precast and glass fiber reinforced concrete (GFRC), the design team ultimately selected the aluminum rainscreen panels that will clad the façade. As Smith put it, “Terracotta was found to be prohibitively expensive, and precast would have required an increase in foundation size and presented construction sequencing problems.” The design team considered the repetition of the facade panels and although, as Smith noted, they appear quite regular, there will be a number of unique aspects to a facade that only rises on two floors.
Aluminum rainscreen panels provide flexibility and room for adjustments during the manufacturing process that would not have been possible with GFRC. The design team worked with Kinetica to finalize the panel configurations, and with a full-scale mockup, the kdA team decided to deepen the facade “as much as possible” within the confines of the materials. Behind the rainscreen panels, in order from outside to inside, will be: a set of aluminum sub-spacers manufactured by Kinetica; two-inch continuous rigid outer mineral wool insulation made by Rockwool; a fluid applied air barrier; exterior gypsum panels; and cold-formed steel framing and batt insulation.
Although the main function of the awning is shading, photovoltaic panels will be installed on the roof to minimize the need for additional cooling inside. As Smith described it, the panels were planned “once the shape of the canopy was established”, with the final quantity of panels expected to cover 90% of the building’s annual energy demand. KdA modeled various canopy shapes and, in collaboration with Transsolar, optimized the canopy geometry “to reduce peak gains during the hottest times of the year.” The canopy will also feature aluminum louvers whose perforation patterns have been designed so as not to interrupt natural lighting.
The construction process benefited from design assistance from Kinetica on the liner, Nordic with CLT and general contractor WS Bellows, who led the coordination. Smith described the workflow as “highly collaborative,” with information sharing between the design team and contractors executed through 3D models. Smith added that this kept “the project on track” and “accelerated coordination issues”. Difficulties came with supply chain issues, requiring the design team to be very flexible in considering alternative products to keep the accelerated project on schedule. Despite this, and the industry’s focus on supply chain issues this year, Smith said rain delays during excavation were the most tedious aspect of the construction process. Smith further added that the project was able to stay on track, with contractors remaining “extremely diligent” in following Covid restrictions to keep workers safe.