With CSTO’s input, the team developed a scope of work, including a super-insulated shell of R-40 white reflective roofing and R-41 metal façade cladding to be applied directly over existing exterior concrete and brick. New fiberglass casements and French doors (R-5) would replace the leaky aluminum units. Extensive internal air sealing would be applied between individual apartments and between the apartments and outdoors. A new boiler and hot-water plant would be added, rated at 94.5 percent efficiency, leading to hydronic baseboards in the apartments. For preheating domestic hot water, a new solar water-heating system would be added to the rooftop.
Other major changes would include swapping out low-efficiency air conditioners for 9.9 EER Energy Star package units, as well as adding Energy Star refrigerators. The building’s exhaust ventilation system would be renovated by sealing it with a material that is applied to the inside of the ducts via access from the roof and then utilizing constant-air regulator dampers; fresh-air trickle vents also would be added.
CFLs or LED lighting would be installed in hallways, lobbies, kitchens, bathrooms and exterior walls. Low-flow plumbing fixtures, including 0.5-gallon-per-minute (gpm) lavatory aerators, 1.5-gpm kitchen-sink aerators and 2-gpm showerheads, would further reduce energy draw while saving water. Flushometers also would be added to existing toilets, and replacement toilets would be 1.3-gallon-per-flush models.
The exterior retrofit strategy was critical to the project’s success. Completed in May 2012, this project did not displace residents during the extensive construction. “Part of the beauty of a deep-energy retrofit is that it does not require a gut renovation,” Backus says. “This is because the insulation is installed on the outside of the building. Residents can continue to live in their apartments during the renovation.”
More than Meets the Eye
The building’s visual transformation does more than enhance the neighborhood’s aesthetics. The exterior overcladding also increases the building’s insulation value by a factor of 10, which—in combination with air sealing—reduces Castle Square’s annual heating and cooling needs by 61 and 68 percent, respectively.
The high-performance exterior retrofit incorporates three distinct elements: First, a liquid-applied air- and water-control membrane is painted onto the original concrete and brick walls, adding a water-control layer to keep air and moisture from getting in. Then, a mineral-fiber blanket is laid over the membrane, which suppresses airflow and improves water drainage. The mineral fiber also reduces air movement and negates the “chimney effect” of warm air rising quickly during cold weather, which can compromise insulation effectiveness.
The insulated metal panels were installed on the exterior side of the mineral fiber. The panels include a rigid, high-density foam sandwiched between durable metal sheets. The panels deliver insulation; shed rain and
snow; and present an attractive building finish. The 5-inch-thick metal panels feature insulation performance about twice that of wall systems built to current code. Altogether, the enclosure retrofit delivers the lion’s share of the uncommonly high energy savings.
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I just learned this project did, in fact, achieve Platinum LEED certification.