That old telephone building on Grant Avenue outside Chinatown's gate never looked so good.

The oversized columns gleam with fresh white paint, and the plaster medallions on the elaborate
cornice have golden highlights. The arch over the entryway includes a pair of stone pediments
that curl upward in the middle like arched eyebrows.

The overall effect is classical but slightly crazed -- as if a temple were glued onto the front of a
fortress -- and it's hard to imagine that 333 Grant Ave. was built to house switchboards and
phone cables. It looks like a place you'd want to call home.

And that's exactly the idea.

The 1908 structure, designed by the firm Coxhead and Coxhead and declared a San Francisco
landmark in 1981, starts a new life this year with 39 condominiums on the upper six floors. It's at
the vanguard of a movement that could bring hundreds of residential units into Union Square, a
district better known for hotels and high-end shops.

But the cultural aspects of the shift are more important and lasting than the financial ones. They
show how malleable a city can be, absorbing new layers of experiences and lifestyles even when
the outer facades change not at all.

In the case of 333 Grant Ave., it began as the headquarters of the Home Telephone Co.; there
was a fancy ground-floor showroom for paying bills, but upstairs was utilitarian: offices and
switchboards. As decades rolled past, the dramatic facade grew dingy while the block around it
remained an odd transition zone between the retail world of Union Square and Chinatown's
pagoda'd entrance.

While the block stayed in limbo, the bold elegance of Coxhead's architecture survived, but it
couldn't stave off the technological changes and industry consolidation that rendered this
telephone facility obsolete by the mid-'90s.

The next brief chapter in the story is predictable: A developer snatched the landmark with hopes
of capitalizing on the dot-com boom, which went bust, leaving pigeons as the sole tenants for
several years.

Dot-com crash aside, what people do need in San Francisco is a place to live -- or, in this strange
world of extreme incomes, a well-located pied-a- terre. Maefield Development reclaimed 333
Grant Ave. from foreclosure in 2002 and then hired Huntsman Architectural Group to make the
Home's old home work as a true residential address.

The result, most emphatically, is not designed for the masses. Some of the units are as small as
500 square feet; the ones facing the alley on the south and the light well on the north are barely
20 feet from their neighbors. And there's no parking; after all, cars weren't a must-have in 1908.
So what do you get? Curb appeal for starters. Most condo buildings don't come with 40-foot-high
columns as thick as a redwood trunk. The units make up in character what some lack in views;
besides, views are in abundance on the rooftop deck that offers the only-in-San Francisco vista of
the cross atop St. Mary's Church in Chinatown set against Coit Tower.

"Ask someone, 'Who wants to live in a small unit with no parking and little light?' and you get one
sort of answer," says Huntsman principal Mark Harbick. "Ask, 'Who wants to live downtown in a
historic building with great details?' and you get something entirely different."

All the units at 333 Grant sold months ago, at prices ranging from $300, 000 to more than $1
million. Roughly two-thirds of the units will be occupied on a full-time basis, and two were sold to
low-income residents as part of the city's affordable housing requirements.

Even if such conversions become a full-scale trend, they're not a cure for the city's housing crisis;
the numbers are relatively small, and the target market is the well-to-do with plenty of other
options (though if several buildings hit the market at once, at least one developer would be smart
enough to aim his or her "product" at first-time buyers).

But it's still a trend to be welcomed.

Look past 333 Grant's vigorous eccentricity, and there are dozens of buildings like it around
Union Square: sturdy structures dating from a time when small dark offices above shops and
restaurants were the norm. The kind of building where "Spade and Archer" might be stenciled on
a door along the hallway.

But now those buildings need seismic work, the wiring's old, and in the current real estate
climate, they aren't much cheaper to rent than the lower floors of a modern office tower. There's
no real reason to keep them -- except for the fact that they're irreplaceable to San Francisco's
character.

What the residential option offers is a lifeline, a financial reason for giving these buildings the care
and purpose they need to survive.

San Francisco isn't unrivaled in the challenge of what to do with older buildings; look no further
than Oakland's Broadway for a wonderful 1920s terrain badly in need of restoration. But in the
case of Union Square, housing costs are at a point where a project like 333 Grant makes sense.
As expensive as it is to bring small, older buildings up to code, there is a reasonable guarantee
that people will want to buy the finished product.

The buildings aren't the only beneficiary in all of this. So is Union Square. The addition of
neighborhood residents to the throngs of shoppers and tourists adds a round-the-clock dimension
that should make the fabled district feel more like part of the city around it.
We're talking about a subtle extra layer rather than a transformation; Grant Avenue tenants such
as Hermes or Armani aren't likely to be replaced by dry cleaners.

Even so, the concept of urban life is growing more complex before our eyes. In the process,
anchors to the past such as 333 Grant Ave. are being strengthened -- and they aren't going
away.