Manayunk church prepares for floods by turning a Main Street mill into a modern Noah’s Ark

If a building can have nine lives, then the Manayunk mill at Main Street and Shurs Lane surely qualifies. In the 175 years since its maker mortared together chunks of Wissahickon schist to create an all-purpose workspace, it has served as a carriage shop, a foundry, a yarn factory, and a furniture store. In mid-August, the mill began a new life as the home of Citylight Church, a rapidly growing evangelical congregation.

It’s no accident that the two-story mill sits on a narrow strip of land between Main Street and the Schuylkill. The location was seen as a strategic advantage by the mill’s early occupants, who harnessed the river to power their machinery and load finished goods onto ships. While the river would occasionally overflow its banks, the flooding never kept them from using the ground floor to manufacture their products. Their customers were always able to enter the building from a door on the Main Street side.

But climate change has put an end to that. The church has become the first historic Main Street property to leave the ground floor permanently empty in response to the area’s growing flood risk. It’s unlikely to be the last.

As the frequency and severity of storms in the Philadelphia region has increased over the past decade, the communities that line the Schuylkill have had to deal with regular bouts of flooding. Even so, no one was prepared for the damage wrought by Hurricane Ida in 2021. For days, the roiling waters of the Schuylkill lapped at the 12-foot ceiling on the mill’s ground floor, making it look like a one-story building. Long stretches of Main Street were so battered by flooding, the corridor was closed to traffic for weeks. Further downriver, in Center City, the deluge turned the Vine Expressway trench into a canal.

Since then, Philadelphia has been stepping up its storm preparations. With funding from the city and state, the Manayunk and East Falls business associations commissioned an engineering study to identify ways to limit the damage caused by future storms. The report identified big and small infrastructure projects that could help control flooding. But it also noted that, even if the city managed to pull those off, the first floor of many existing structures would never be safe to occupy again.

That observation was a gut punch. Main Street’s buildings are what gives Manayunk’s historic core its distinctive charm, and makes the neighborhood one of Philadelphia’s liveliest business districts. Those buildings can’t simply be written off or demolished.

That’s why we need to pay attention to the Citylight’s mill renovation. Overseen by Fishtown’s Jeremy Avellino, one of the city’s go-to architects for energy-efficient designs, the project has found a way to balance no-nonsense climate adaptation and sensitive historic preservation. In doing so, it offers lessons for other riverfront buildings, both in Manayunk and beyond.

Eager to see the design in action, I stopped by Citylight on a recent Sunday morning for the 9 o’clock service. Temperatures were already in the 80s, yet most worshipers arrived on foot after leaving their cars several blocks away in a remote lot. Many pushed strollers or carried small children. They streamed through a grove of just-planted saplings to the church’s main entrance, which has been relocated on the side of the building.

Because the ground floor was left unfinished and there is no air-conditioning, the moist summer heat radiated off the battered rubble walls. As people made their way to the second-floor landing, they were rewarded with a cool breeze and the sound of song. Worshipers grabbed coffee and caught up with friends in the cafe-style community room, before stepping to a soaring sanctuary, where blonde wood and 19th-century steel trusses tempered the white walls.

Citylight’s leaders readily admit they had only a vague idea of the challenges they faced when they purchased the mill in 2022, a year after Ida. The church, which draws its 500-person congregation largely from Philadelphia’s northwest neighborhoods, had been renting space nearby, in the Mishkan Shalom synagogue. Church leaders liked how Mishkan Shalom had turned a former mill into an airy sanctuary and wanted to replicate the experience in their own building, Jon Chin, Citylight’s executive pastor, told me.

What they didn’t fully appreciate is that Mishkan Shalom sits at the top of a hill, safe from the fury of the river. Even though the Citylight mill, located at 4050 Main St., was still caked with mud when they closed on the property, the church leaders optimistically assumed it would be a simple matter to clean up the damage.

It took a series of conversations with Avellino, the Federal Emergency Management Agency, and the Philadelphia Historical Commission before Citylight realized the choice was more difficult: Either the church would have to spend massive amounts of money to floodproof the lower floor — a longshot effort that might not succeed — or they could try to pack the entire church onto the second floor, including offices, classrooms, kitchen, and sanctuary. In that case, the lower level would have to be left empty — “abandoned” in the parlance of flood-management specialists. It could only be used for a few parking spaces.

The church decided to make the sacrifice.

Avellino proved to be the perfect partner for the project. Since founding his firm, Bright Common, he has specialized in an extreme version of green architecture called Passive House design. Far more rigorous than the better-known LEED standard, the system produces buildings that use very little energy for heating and cooling. Having already given up half the building to avoid flooding, Citylight agreed to let Avellino make the building even more sustainable by renovating the upper floor according to Passive House principles.

Creating a Passive House building is not for the faint of heart. To reduce energy consumption, the building’s exterior needs to be sealed as tight as a submarine. Avellino persuaded the church to invest in tight-fitting, German-made, triple-pane windows that can withstand intense storms.

Every crack and opening was sealed, and the walls were stuffed with insulation made from cardboard shipping boxes and shredded newspapers. Those superinsulated walls are two feet thick. Once worshipers get to the second floor, they must pass through a set of heavy, insulated doors, which act as an air lock, into the climate-controlled sanctuary.

“We treated the building as an ark,” explained Avellino.

Before the Trump administration eliminated a tax credit for solar panels, Avellino had planned to power the building entirely from the sun’s energy. That probably won’t happen now, but the church is still an all-electric building.

The renovation ended up costing the church $7.5 million, which works out to $500 a square foot. But Citylight members, who are part of the Christian and Missionary Alliance, told me they feel the bible provides justification for the expense. ”If God is the creator of everything, then we should want his creation to be taken care of,” explained Matt Cohen, Citylight’s lead pastor.

Manayunk’s civic groups are thrilled with the transformation, too. The former mill is in the most low-lying stretch of Main Street, and the area is likely to flood even during modest storms. Lower Main Street, around Shurs Lane, has become a sad, underpopulated place in recent years. Although several apartment projects have been approved, none have gone forward because of the challenges of shoring up the buildings against flooding. The presence of so many unused buildings and empty lots is sapping Main Street’s energy, said Gwen McCauley, who runs the Manayunk Development Corp.

Figuring out how to protect the ground floors isn’t the only challenge apartment developers face. They also need to make sure residents can safely leave their buildings during a flood. But with the river on one side, and Manayunk’s steep hills on the other, the terrain makes it difficult to carve out a viable escape route, said John Hunter, an architect who chairs the Manayunk Neighborhood Council’s zoning committee.

As an alternative, Hunter said, Manayunk residents would like to see the city or state acquire some of the empty lots along the river and turn them into resiliency parks that could absorb water during a storm. They also want to limit new housing construction on Venice Island.

Instead, the city has allowed more and more housing to be built on the island, a narrow spit of land that runs parallel to Main Street. Even though a bridge to Manayunk proper was meant to serve as an escape route during floods, dozens of people were nevertheless stranded in their apartments during Ida.

Venice Island has a long and contentious history. The island was created in the early 19th century, using fill removed during the construction of the Manayunk Canal. Since the land was zoned industrial back then, there were just a few factories on the island. But after those industries died off in the early 2000s, then-Councilmember Michael A. Nutter pushed to remove the floodway designation and rezone the island for residential construction.

To prevent those new apartments and townhouses from flooding, even during modest storms, developers needed to raise the height of their land. They did that by bringing in large quantities of dirt fill and spreading it across their sites.

Raising the height of Venice Island has made Manayunk’s flooding even worse, experts say. As the island gets taller, it acts as a kind of dam, displacing and channeling water onto the mainland during storms. “It’s like adding more and more toys to a bathtub. The water rises and it eventually spills over,” explained Josh Lippert, who served as Philadelphia’s first floodplain manager, and now works in Delaware.

Still, developers keep building there. A.P. Construction, a South Jersey company that owns 30 acres at the northern end of Venice Island, has been trucking in huge quantities of fill recently, even though there is no approved project for the site yet.

Ironically, the only way to make residential buildings there safe is to abandon the ground floor — just as Citylight did to adapt its Main Street mill — and use it for parking. That sort of urban design isn’t attractive, and doesn’t foster neighborhood life, but allows developers to continue monetizing land in flood-prone areas.

At a time when the Trump administration is cutting staff at FEMA and eliminating Biden-era programs aimed at slowing climate change, building in floodplains will become ever more dangerous. But if storms get worse, abandoning the ground floor might turn out to be just a stopgap. Let’s pray that Citylight’s strategy works.