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How the rise of the basement apartment explains Philadelphia’s latest rash of housing collapses | Inga Saffron

More density in old rowhouse neighborhoods adds to the pressure.

Two workers were trapped and then rescued when building collapsed at Ridge Avenue and Vineyard Street in North Philadelphia on Dec. 21, 2018.
Two workers were trapped and then rescued when building collapsed at Ridge Avenue and Vineyard Street in North Philadelphia on Dec. 21, 2018.Read moreTommy Rowan / Staff

From the moment that work started last September on a nine-unit condo building next to their 18th-century Queen Village home, Adam Knowles and Debjani Bhattacharyya felt something wasn’t right. Their house shook. Cracks and wet patches appeared on their walls. As their fears mounted, they blitzed city officials with emails, begging for more oversight. The couple became social media Cassandras, taking to Twitter to warn anyone who would listen that something terrible was about to happen.

Then, it did.

On July 30 — 10 months after they hit “send” on the first of dozens of complaints — a contractor for J. Roller Development accidentally slammed a chunk of concrete into the foundation of their home while excavating the neighboring site for a basement condo. Philadelphia building officials immediately declared the historic house at 211 Monroe St. unsafe and ordered Jacob Roller to stop construction. Knowles and Bhattacharyya, both professors at Drexel University, were exiled to a furnished apartment, and their lives turned upside down.

What happened on Monroe Street represents the dark side of Philadelphia’s long-running, and mostly beneficial, housing boom, and should serve as a cautionary tale for future development.

With more novice developers rushing to get into the construction game, more existing rowhouses are being compromised. So far this year, six occupied homes have been reduced to dust, up from just two in all of 2018. It’s a miracle that no one has died.

Those numbers don’t tell the whole story, though. Because the Department of Licenses and Inspections doesn’t track less-serious incidents — like the one at Knowles and Bhattacharyya’s home — no one knows exactly how many other houses have suffered serious damage yet remain standing. But there is plenty of anecdotal evidence to suggest that such incidents are becoming more common. A Facebook site founded by community activist Venise Whitaker, the Riverwards L+I Coalition, regularly chronicles the collateral damage from new construction. Hardly a day goes by without a new post.

Collapsing rowhouses are nothing new in Philadelphia. Unlike cities where people live in large apartment houses or, conversely, in freestanding single-family homes, Philadelphia’s tightly packed rowhouse neighborhoods are particularly vulnerable to disturbances, from heavy rain to new construction. Most of our redbrick houses were built before 1940 and many sit on rubble foundations, with no mortar to bind the stones together. Construction imposes even more stresses. Inserting a new rowhouse onto a 16-foot-wide infill lot is like juggling while walking on a tightrope. One slip and everything comes tumbling down in a hail of bricks.

But there is another factor that has dramatically increased the risk of collapse, according to L&I Commissioner David Perri: Developers are now cramming bigger buildings and more units onto rowhouse-sized sites. Single-family homes become duplexes, triplexes, even quad-plexes. Although it sometimes feels like the whole city is a construction site, most of this new housing is concentrated in just a few highly desirable neighborhoods. As the supply of infill sites in those places shrinks, land prices have soared. Developers now feel they must use every available inch of their property to maximize their return.

There are two ways they can do that: Build up, or build down. Adding a third or fourth floor to an existing house is the easiest way to increase the square footage. But because the zoning code caps the height of rowhouses at 38 feet in most places — barely enough for a four-story structure — developers are choosing to build down. Virtually every new multiunit building in the city, as well as many single family homes, now includes a full-height basement.

“If you’re already excavating for the foundation, it’s a cheap way to get more square-footage,” explained Nino Cutrofello, development director at Callahan Ward, the company that built the unusually skinny apartment house at 12th and Vine, which includes a basement apartment. But to carve out the nine-foot ceilings that tenants expect, developers need to dig down nearly 14 feet — far below the foundations of older homes.

The problem is, the deeper builders go, the more likely they are to disturb the fragile rowhouse next door. That’s what happened when a Fishtown developer working without permits collapsed an elderly woman’s home on Thompson Street in February. That’s what happened a month later when another Fishtown developer, also working without proper permits, destroyed a pair of 19th-century homes on Tulip Street.

And that’s pretty much what happened on Monroe Street. The difference — a crucial one — is that, in this case, the developer had obtained all the necessary permits from L&I and was being routinely monitored by inspectors.

As a result, the damage to 211 Monroe St. is relatively modest, at least in comparison to the devastation in the two Fishtown cases. After Knowles and Bhattacharyya went on their email offensive this spring, Perri ordered Roller to install steel bracing to protect the party wall, at a cost of $60,000 to the developer. Roller was also required to hire an engineer to oversee the contractors.

Without those measures, Perri told me in an interview, the Monroe Street party wall could have probably tumbled just like the ones in Fishtown. Assuming Roller completes foundation repairs according to L&I’s specifications, Perri said the couple could be back in their house by next week.

That doesn’t mean all’s well that ends well. Given that Monroe Street is one of the oldest parts of Philadelphia, and that the area is known for its shifting soil, Knowles and Bhattacharyya want to know why L&I permitted Roller to build what he calls “English basements” next to their historically designated, Colonial-era home. “Our interactions with L&I frequently gave us the impression that they were advocates for the developer,” Knowles complained.

Developers counter that they are caught in a bind. It’s far easier to get extra space by building up, but most neighborhood groups recoil at the prospect. “We would have loved for our building to be higher, but we didn’t dare ask for a variance. That’s the third rail of zoning,” Roller explained. “Construction is expensive. How do you get the most yield from the site?”

You hear that refrain a lot these days. After a West Philadelphia developer agreed to save a church on 46th Street, he also insisted on squeezing in basement apartments so he could meet his target numbers. That kind of work requires extra-delicate construction. Builders must reinforce foundations of the neighboring building, a costly technique called underpinning. Not every contractor is up to the task.

Does anyone really want to live underground? Apparently, yes, assuming the basement unit has a reasonable amount of light. At Callahan Ward’s Vine Street project, the architects at ISA created a below-grade patio to help illuminate the apartment. Another developer, Greentree Group, followed the same strategy at its just-completed rental apartments on North Front Street.

If that’s now going to be the norm, L&I is going to have to step up enforcement. Right now, Perri concedes, it can take 10 days for a 311 call to reach his office. Even when contractors are caught working without permits or using improper techniques, the fines are too small to get them to change their ways. It takes too long for L&I to revoke a bad contractor’s license. Even then, as Whitaker has repeatedly observed in Fishtown, they simply reconstitute themselves under a new corporate name.

Because excavation is often the most dangerous part of house-building in Philadelphia, Perri said his department wants to create a special license for contractors who build foundations. That would eliminate dozens of fly-by-nights. He agrees that faster enforcement and heftier fines are also necessary.

What we know is that developers can’t keep treating collateral damage to neighboring properties as the cost of doing business. These are people’s homes and lives.