This fall, New York artist Roxy Paine is heading to Chicago to exhibit his life-size diorama of a fast-food restaurant carved from birch wood, down to the straws. In Paris, German artist Georg Baselitz is about to unveil his show of 12-foot-tall bronze women. Next week in New York, Matthew Day Jackson will roll out his latest creation -- a 13-foot-long roadster designed by his uncle, built by his cousin and wrecked, temporarily, by his crew on a New Jersey track.

Just don't look for any of this art in a museum -- yet. Thanks to a resurgent global-art market, some of the world's top dealers are feeling flush and fueling a new gallery building boom -- transforming factories, roller rinks and airplane hangars into showrooms for contemporary art. As a result, some of the most highly anticipated shows of the season are set to open in galleries, not museums.

Increasingly, the artworks on display are just as enormous, requiring cranes and teams of workers to display. Museums were once the only potential buyers for such room-filling pieces, but over the past decade an influx of wealthy collectors around the world has started buying ever-larger art trophies. All of it has prompted dealers to seek out artists whose work is hefty enough to stand out from afar -- a prioritizing by size that never occurred in past generations, dealers say.

White Cube caused a stir nearly two years ago when it opened a 58,000 square-foot gallery in south London. That's bigger than a football field. In January, Swiss gallery Hauser & Wirth converted a former roller rink and nightclub in New York's Chelsea neighborhood into a 24,700 square-foot gallery -- complete with an artist-designed bar serving free coffee on weekends. 'We don't need to sell coffee,' said director Marc Payot.

Austrian dealer Thaddaeus Ropac opened the world's second-largest gallery last October when he transformed a group of eight factory buildings on Paris's outskirts into a 50,000 square-foot art complex. The $10 million space has allowed him to carve up areas for performance art and outfit several apartments for visiting artists like Anselm Kiefer. But recently, Mr. Ropac realized that his artists didn't want to use the complex's studio for fear of attracting onlookers, so he's rented even more space a few blocks away. 'I don't want my artists to feel like they're in a zoo,' he said

Like museums, some gallery spaces now boast auditoriums, screening rooms, roof gardens and bookstores. Shows at the dozen biggest galleries are often planned two years in advance and can take more than a month to install. Once up, the art may also stay on view for several months at a time, a typical time frame for a museum exhibit but a fresh stretch for a gallerysetting more accustomed to opening new shows monthly.

New York dealer Larry Gagosian, among the first to champion this supersize-gallery model, is also known for showing big artworks to match. His two biggest galleries in New York are closed for the next six weeks -- right through the opening of the fall season -- because one of his artists, sculptor Richard Serra, requires that much time just to install his show opening Oct. 26. Mr. Serra is known for creating enormous steel sculptures, many of them so curved and rust-colored they evoke ship hulls. This time around, Mr. Serra said some of his 40-foot-long steel pieces for the coming show don't curve at all and are instead free-standing plates set at sharp angles, 'a new shape for me,' he said. To make sure these pieces would fit into Gagosian's galleries, the artist said he rented a warehouse with similar dimensions in New Jersey. Then he slid in wooden versions of each piece. They all fit.

'You don't bring in 367 tons of steel without knowing what you're getting into,' Mr. Serra added.

These mega-galleries could be a sign of market-fueled hubris -- but they may simply represent the next evolutionary step in the look of a modern-day art gallery, architects and dealers say. Either way, these spaces are changing the way we see, and shop for, art. A century ago, art galleries from New York to London and beyond sought to evoke a clubby townhouse with decor as ornate as their paintings' gilded frames. After the devastation of World War II, galleries removed their lavish adornments so as not to compete with their artists' wildly splattered abstractions. Canvases got wider and sculptures got a little bulkier, but just about everything on offer could still fit within the confines of an apartment with a 9-foot ceiling. All that changed in the 1960s as galleries began clustering in the New York neighborhood of Soho with its tall, cast-iron window casements, tin ceilings and wooden floors.

The loft-style look took over, and for the first time, dealers began presenting art to buyers in the same kind of industrial spaces where artists were also producing it -- a syncing up that resulted in even-larger pieces that looked best in wide-open rooms to match. By the 1980s, New York dealers had migrated to the bigger garages and depots of nearby Chelsea and the gallery look formed there has become today's industry standard, said architect Richard Gluckman, who has designed at least 40 galleries over that span. Walk into any galleryanywhere in the world, and look for its telltale markers: Concrete floors, white walls, skylights and an open-plan layout that can accommodate unwieldy pieces.

For their part, dealers say they had to expand their gallery footprints because their artists asked for more room to display ambitious pieces. To remain competitive -- and keep their stars from defecting to rivals -- dealers had little choice but to keep pace, said Emanuel Aguilar, a director at Chicago's Kavi Gupta Gallery. That's the main reason why his gallery will open a second, 8,000 square-foot gallery on Sept. 20 near its original space in Chicago's West Loop. The opening show is Mr. Paine's birch eaterie, plus a life-size metal replica of a control room at a nuclear power plant, both to be shown under glass.

Tim Marlow, a director at White Cube, says the phenomenon is 'artist-led, and the market is following.'

In classic chicken-or-the-egg fashion, some artists said they could take or leave the extra room but said their dealers were opening bigger spaces to enticeadditional artists -- and collectors. Mr. Jackson, the artist working on the race car, said he didn't ask for more room from Hauser & Wirth, but he does like the flexibility that its 24,700 square-foot gallery in Chelsea offers.

For next week's show, Mr. Jackson chose to build several floor-to-ceiling, drywall partitions spaced at various intervals along its main gallery to serve as dividers between his larger sculptures and paintings. In addition to the car, he's unveiling a series of life-size sculptures based on snapshots of Michelangelo's Pieta, an iconic statue of Mary holding a crucified Christ, and Auguste Rodin's 1889 scene of 'Burghers of Calais.'

Last week, his dealer Mr. Payot took a walk through the main hall of the gallery as Mr. Jackson's installation got under way. The partitions were already up and covered in plain, wooden siding, but workers were still waiting for the multi-ton sculptures and the car to be delivered. Without them, the long, skylit room looked as big as an empty supermarket.

Miami collector Dennis Scholl said he has seen shows in commercial spaces lately that would make any museum director salivate, but the 'intimate' feeling of strolling through a cozy space is also gone. Instead, Mr. Scholl said, 'The mega spaces project what they need to -- a level of power and gravitas.'

The emphasis on large-scale art could have long-lasting implications on art values. Until recently, the art elite placed a premium on Pablo Picasso's small, early Blue Period paintings over his larger, and later, musketeers. Today, an artist's biggest work may also be his priciest at auction -- whether or not that particular piece amounts to a career milestone. At the height of the last market cycle, Russian collector Roman Abramovich paid Sotheby's a record-setting $86.3 million for a Francis Bacon 'Triptych, 1976' that included three sea-green panels, each over 6-feet tall.

Sotheby's specialist Alex Rotter said he credits the 'super galleries' for convincing newer collectors to buy extra-large art. Mr. Rotter, who helps oversee Sotheby's in-house galleries S2, said he's also learning firsthand that some artworks look, and fare, better in vast concrete surroundings than others. 'For Richard Serra, it's not hard to fill a space,' he said, 'but if you give 5,000 square feet to someone else, there's a chance some of it will feel like filler -- not all of it is good.'

Mr. Serra concurs. 'Everyone has different needs, but galleries shouldn't be expanding as a rule, that's silly,' he said. 'Bigness in itself isn't a virtue.'

How big is too big? That's the parlor-game question of the gallery world right now, and there is no easy answer. Mr. Payot, who is now scouting spaces for another Hauser & Wirth outpost in Los Angeles, said he doesn't want anything less than 10,000 square feet. But plenty of small to midsize dealers are wrestling with the wisdom and feasibility of taking on more space. Casey Kaplan, a dealer known for representing artists like Liam Gillick, has steadily expanded his gallery's footprint over the past two decades from a 400 square-foot room in Soho to his current 5,000 square-foot ground-floor space in Chelsea. But last week, Mr. Kaplan said he is planning to move out of the neighborhood when his lease runs out in 2015 -- and he isn't sure whether he will lease somewhere larger or scale back.

Mr. Kaplan said he has wearied of Chelsea's 'obsession' with real-estate issues and wonders if the shoptalk will swivel back to art if he rents farther afield, say Harlem. 'People come in now and they don't want to talk about art-they want to talk about how big some gallery is or whether I'm going to franchise,' he said. 'It's a shift I'm not into.'

In some instances, oversize galleries are accelerating the long-standing pas de deux between art-led gentrification and real estate development. In Culver City, Calif., the 2009 expansion of powerhouse gallery Blum & Poe into a 22,000-square foot space on the corner of Washington and La Cienega Boulevards encouraged a cluster of younger galleries to open nearby. In an established hub like Chelsea, though, a behemoth gallery seeking to expand may need to push out a few smaller ones on either side.

In fact, the mega-galleries say they have already started experimenting with ways to make their own spaces more inviting. After Hauser & Wirth moved to Chelsea last year, the gallery kept its former home-a townhouse on the Upper East Side-so it can mount shows there that might appear drowned out downtown. Next up: An historical show of Brazilian Constructivist art, much of it geometrical drawings and paintings.