The slew of old Boston Wharf Co. industrial buildings in the Fort Point Channel area were great for storing woolens, making leather, and later, for selling furniture. Now, though, developers are starting to transform the vast floors of high-ceilinged brick-and-beam construction into cozy, quiet luxury residences.

But new plumbing, wiring, and interior walls won't be enough. Steel building frames will be needed to support the structures.

Taking the first complex of buildings to luxury levels involves complicated adaptation that includes new support columns from basement to roof, constructing concrete walls just inside the handsome brick facades, and creating an interior "cage" of structural steel to stiffen walls and floors crafted over 100 years ago.

In April, Berkeley Investments Inc. started turning two five-story buildings and an adjacent vacant lot on Congress Street into FP3, a $60 million luxury-living complex scheduled to open next spring.

"It's cheaper to just knock this down and build a new [steel building]," said Scott Thomson, lead architect on the project and a senior associate with Hacin & Associates Inc., pointing to 348-354 Congress, the gutted former Boston Wharf Co. warehouses. "Our culture has realized what's of value, so now we have this strange challenge."

The strange - and expensive - challenge is to preserve a historic building and capture the charm of Boston's maritime and industrial past for a 21st century neighborhood, with condos built over retail shops, galleries, and restaurants. And to justify prices ranging from $350,000 to $2 million or more per home.

In 2004, Berkeley Investments purchased a dozen properties on and around Congress Street. Another developer is planning a similar transformation to this kind of steel building complex on Summer Street, a block to the south. But Berkeley was the first to break ground, with this 97-unit complex of condos between Thomson Place and Pittsburgh Street.

Since the heavy industrial use of the early 20th century, the properties have been empty or used as cheap office space. Buildings from that era are strong enough to support the loads of a typical residential building. These have thick white-pine floors, 18-inch wooden beams, and brick walls 2-feet thick at ground level. But Berkeley is constructing several garden units - three modern glass-and-steel floors - on top of the existing five-story structures, so that additional weight must be supported with general steel building beams.

In the end, the building has to hold its own weight, that of its contents, and the weight of whatever comes with New England snowstorms. It also must withstand nor'easter winds - not a big factor in a building of only eight floors - but be stable enough to withstand strong jolting forces, such as from an earthquake, that otherwise could cause a collapse.

To continue reading this Boston Globe article, click here.