Wednesday, September 12, 2007

Zahid Sardar

Howard Street Gallery

When the American Institute of Architects' tour of San Francisco homes gets under way this weekend, as part of Architecture and the City Month, participants will encounter many fresh ideas - or at least find arresting interpretations of what we already know or have seen before - but none stands out as entirely new for San Francisco.

Instead, as people scoot around from Diamond Heights, to Ocean Beach, to Potrero Hill to the Mission and several South of Market locations to view modern, contemporary homes, they might pause in front of something that is indeed a fascinating first for the city: a facade composed of electrically operated aluminum louvers.

The building, at 1234 Howard St., is designed by Stanley Saitowitz of Natoma Architects, a firm participating in this year's AIA San Francisco Living Home Tour. The 18-unit building has a square, 50-by-50-foot facade with floor-to-ceiling windows and sliding glass doors, all shaded by the exterior louvered blinds. Above the ground floor, a four-story high, 12-foot-wide light well spanned by glass or metal bridges, cleaves the middle of the structure, front to back. It is a remarkable addition to the streetscape. The blinds and exposed bridges are as startlingly beautiful as Saitowitz's 2002 poured-concrete Yerba Buena lofts on Folsom Street, which are articulated with all-glass bays that glow at night.

But while the Yerba Buena lofts' fixed channel-glass bays are translucent and inoperable, this animated, interactive face at Howard Street allows street views, light and air because the windows slide open and the blinds can be adjusted at will.

"On this south face, we wanted to optimize light and air but also to easily protect from sunlight," Saitowitz said.

With just a toggle switch, homeowners can adjust the angle of the blinds to achieve unexpected combinations of light, shade and pattern throughout the day.

The technology is not at all new. Such electrical shades are commonly used in Europe to alleviate high energy costs. "Now everyone here also needs to pay attention to such ideas," Saitowitz said.

He found the standard off-the-shelf Belgian components for the facade through a company in Florida where they are used as hurricane shields. "Used as they are here, they are a green design because they maximize daylight and block heat gain," Saitowitz said.

There is no solar power in the building yet, but, Saitowitz insists, very little electricity is used to operate the blinds.

Add to that the fact that the aluminum is virtually maintenance free, and you have an ultra-green concept. Even when it fails, the system installed on vertical channels is repairable or replaceable easily because it is not used as a waterproofing layer. It just acts as an insulating layer and helps to shield light. Since a separate motor operates each blind, if one fails, it does not affect the others.

Saitowitz said this modern design concept was used in older buildings but got lost when glass curtain walls became the preferred look in high-rise architecture. In Italy, for instance, exterior shutters, interior blinds, curtains and drapes were traditionally used to ward off extreme seasonal heat or cold. "They were layered facades that were extremely utilitarian," Saitowitz said.

The Federal Building on Mission Street by Thom Mayne also uses scrims and several layers to achieve some of the energy-saving goals of Saitowitz's design, but they are not as simple or interactive.

Another older idea that is used innovatively at 1234 Howard St. is the use of a central courtyard to accommodate code restrictions on land use. In the South of Market area, mixed-use buildings can extend to the perimeter of the lot in every direction, but the city requires at least a quarter of the lot to be left open as yard space for residences. Saitowitz's design makes this code constraint a virtue by moving the rear yard into the center.

"Traditional Mediterranean architecture uses a central yard, and here we use it as a pool of tranquility as well as a light well," said Saitowitz.

"Basically we set each unit in a long bar plan like the single-family country homes we've been developing at our office. This is the urban version of that planning strategy."

A few translucent glass screens or short walls for privacy within each bar-shaped unit make the loft-like open-plan flats flexible. This simplified new direction for urban buildings is also cost-effective, Saitowitz said, and he spent about $200 a square foot to build his design.

Each of the 18 large or small, but always slender, condominiums is stacked four levels high on each side of the central light well.

Daylight enters along the length of each unit. "Typically, urban housing has little exposure to natural daylight," noted Saitowitz.

A couple of street-side accessible lofts open on Natoma Street. Perforated aluminum doors and screens facing Howard Street camouflage wide garage doors and the elegant - but dark - boulder-lined lobby entrance.

"The aluminum screens make all that nearly invisible," said Saitowitz.

Nonetheless, go see it if you can.

Modular home demo

A modular home will be constructed in three days during the Dwell on Design Conference and Exhibition, also homebase for the AIA house tour, Friday-Sunday. Composed of prefabricated parts, the InstaHouse will show how to build an inexpensive 168-square-foot cottage with decks and a sloped shed roof.

"I thought we could build this house in three days," said architect Jim Zack, who recently completed his own home in the Glen Park neighborhood of San Francisco (on SFGate.com, see "Panel discussion: A cost-cutting building system could change custom home design, making production faster and less wasteful," June 20) using Forma Homes' prefabricated wood components. But, with less time available, they will use some pre-insulated metal-clad panels from API and Bonelli windows.

"But we acknowledge that failure to complete the structure is an option because in the end we merely want to show the process," said Zack.

-- For details call Zack/de Vito Architecture and BuiltForm Construction at (415) 495-7889.

-- For complete Architecture and the City festival details: www.aiasf.org/archandcity.

-- To download the festival guide, go to links.sfgate.com/ZSX.

- Zahid Sardar

Zahid Sardar is the Chronicle design editor. E-mail your comments and ideas for Design Spotting to him at zsardar@sfchronicle.com.