• Encouraging community interaction is a chief goal for Andersson. To that end, he laid out terraces at the street and mezzanine levels as inviting public spaces—including vantage points for watching live televised broadcasts of “Austin City Limits.”

    Credit: Andersson–Wise Architects

    Encouraging community interaction is a chief goal for Andersson. To that end, he laid out terraces at the street and mezzanine levels as inviting public spaces—including vantage points for watching live televised broadcasts of “Austin City Limits.”
Arthur Andersson, AIA, looked to Southwestern cliff dwellings when designing Block 21 in Austin, Texas. The mixed-use project contains the television studios and performance venue for “Austin City Limits,” office and retail space topped by a W hotel, and private residences. Those high-rise caves inspired him to design shaded balconies carved into the east and west façades, for longer hours of daylight without heat gain.

Shading is key, because staving off the Texas heat consumes large amounts of energy. The project's high-performance glazing blocks UV rays and reflects heat away from interiors while providing natural light. But the building still needs cooling, so Andersson found an alternative method in Austin's central water-chiller system. “You buy cold water from the city's central chiller and when it gets hot, you send it back,” he explains. “But we're designing an intermediate step where we send the water through a heat-recovery system.” That step garners heat for the building and saves energy for the central chiller.

Another innovative idea helped shrink the parking structure. The 37-story building requires mostly nighttime and weekend parking, while nearby commercial buildings use garages during business hours. A shared parking agreement lets Andersson get away with just 450 spots—about half the usual requirement. Block 21 currently qualifies for LEED Platinum status, and the team feels strongly they'll be able to maintain that status throughout construction, which concludes in 2010.

  • site plan

    Credit: Andersson–Wise Architects

    site plan
project: Block 21, Austin, Texas

key green strategies: Green roof, xeriscaping, low-flow fixtures, low-VOC paints and adhesives, local materials, optimal daylighting, on-site recycling, high-performance glazing, central water-chiller system, and mixed-use

architect: Andersson–Wise Architects, Austin

architect of record: BOKA Powell, Dallas

developer: Stratus Properties, Austin

general contractor: Austin Commercial, Austin

project size: 638 square feet to 4,204 square feet per unit

site size: 1.76 acres

construction cost: $275 per square foot

sales price: $300,000 to $1.5 million per unit

units in project: 196 (plus 250 hotel rooms)