Not one chair from Mies van der Rohe’s breakthrough Barcelona Pavilion from 1929 survives today. After the World’s Fair came to a close, organizers disassembled the entire structure and threw away all of its Modernist furnishings, chairs and all.

That’s a far cry from the fate of the Artek Pavilion, the most notable lot in tomorrow’s 20th Century Design auction at Sotheby’s. The prefabricated structure, built for the 2007 Salone Internazionale del Mobile in Milan, will hit the block with a sale estimate of between $800,000 and $1.2 million.

It’s a clear sign that architecture aficionados are coming to view such pavilions and their contents as more than just temporary, World’s Fair-style displays. “The work itself is a noble experiment,” the senior vice president and head of the 20th-century design department at Sotheby’s, James Zemaitis, said. “So is selling it at auction.”

That’s because Sotheby’s has chosen to sell the structure as artwork instead of as a piece of real estate. By doing so, tomorrow’s buyer at Sotheby’s, freed from the boundaries of a traditional real estate transaction, will be able to pack up and transport the 38-ton pavilion anywhere in the world.

The Japanese architect Shigeru Ban designed the Artek Pavilion in 21 interlocking modules that can be erected in any number of combinations, depending on space. (It is more than 131 feet long if all the modules are assembled end-to-end.) Mr. Zemaitis said he expects that contemporary art buyers who are building weekend homes upstate will be interested in the pavilion because they have the space for it.

“You’d need a good plot of land for this,” Mr. Zemaitis said. “Hybrid collectors, that is to say, people with more than one collection, will appreciate the pavilion as a place to display anything from modern paintings to vintage automobiles.”

Mr. Ban designed the pavilion for the Scandinavian furniture company Artek, founded in 1935 by a group that included the architect Alvar Aalto. In fact, the pavilion that Aalto designed for the Artek display at the 1939 World’s Fair in New York was, like van der Rohe’s Barcelona Pavilion, destroyed shortly after the fair closed.

Tomorrow, the pavilion will almost certainly become the property of a Contemporary art collector. But Mr. Ban has a reputation for catering to a decidedly different crowd: His modular structures are an attempt to address worldwide housing shortages and shoddy housing conditions in Third World countries.

An Artek spokesman confirmed plans to donate profits from the sale of the pavilion to charity. Adding to its hip appeal as an ecologically friendly structure, most of the pavilion is composed of a wood-plastic composite material derived from recycled self-adhesive mailing labels.

“Here’s an architect working under a ‘greater good’ framework and becoming popular because of it,” Mr. Zemaitis said. “Shigeru Ban hasn’t become a [Santiago] Calatrava yet, but he has private developers approaching him and he’s set to take off.”

Also set to take off is interest in prefab housing as works of art. The Museum of Modern Art next month will open “Home Delivery: Fabricating the Modern Dwelling,” in what could be the last use of its open lot on West 54th Street before construction begins on a new museum tower.

“The revolution in mass customization promises a new dialogue between individual desires, site particularities, and artistic innovation,” the Philip Johnson chief curator of MoMA’s department of architecture and design, Barry Bergdoll, said.

The Cooper-Hewitt National Design Museum later this year will present displays from “Tulou,” an affordable housing project in China that will include two full-scale bedrooms.

According to Artek’s creative director, Tom Dixon, people visiting the pavilion during the Milan fair and subsequent Artek displays in Miami and Helsinki, Finland, suggested it could be used as everything from a chapel to a garden center.

Another lot at Sotheby’s auction tomorrow reflects the growing interest in the art of affordable housing. A set of lacquered steel doors designed by Jean Prouvé spent most of the 20th century in a warehouse. They were among extra sets of doors manufactured for the designer’s Maisons Tropicales project in Africa in 1949.

Sotheby’s sold a similar pair of Prouvé doors from the collection of Robert Rudin in 2004 for a record $680,000; the pair up for auction tomorrow has an estimate of between $100,000 and $150,000. “The experience of selling the Prouvé doors in 2004 led people to start thinking about selling entire houses,” Mr. Zemaitis said.

The 2003 Sotheby’s sale of van der Rohe’s Farnsworth House also got people at the auction house to start thinking more about the distinctions between real estate and prefabricated structures.

“Some argued that the Farnsworth House was site-specific and shouldn’t be moved,” Mr. Zemaitis said. “The Artek Pavilion falls into a different category. You can store it in a warehouse if you need to.”