Are Historic Homes More Resilient Against Floods?

When historic homes flood, building contractors are frequently compelled by government regulations to remove the water-logged wood flooring, demolish the old plaster walls, and replace them with new, flood-resistant materials.

Source: AP | Published on October 10, 2022

Historic Home

It's a hurried approach that's likely to be seen throughout southwest Florida in the aftermath of Hurricane Ian. However, restorers Paige Pollard and Kerry Shackelford believe they have discovered something that science has yet to prove: historic building materials can often withstand repeated soakings. They argue that there is frequently no need to install modern products such as box-store lumber, which are both costly to homeowners and dilute a house's historic character.

"Our forefathers chose naturally rot-resistant materials like black locust, red cedar, and cypress," said Shackelford, who owns a historic restoration company. "And they actually outlast many of the products we use today."

Pollard and Shackelford are part of a growing movement in the United States to demonstrate the resilience of older homes as more are threatened by rising seas and intensifying storms as a result of climate change. They hope that their research near Virginia's coast will persuade more government officials and building contractors that historic building materials often require cleaning rather than replacement following a flood.

Historic preservationists in Florida are already concerned that older homes damaged by Ian will be stripped of their original materials because there are so few craftsmen available to perform proper repairs.

"There are some companies that just come in and gut the place and move on," said Jenny Wolfe, board president of the Florida Trust for Historic Preservation.

Building Resilient Solutions, Pollard and Shackelford's joint venture in Virginia, opened a lab this year in which planks of old-growth pine, oak, and cedar are submerged in a tank mimicking flood conditions. The tests were developed with the assistance of Virginia Tech researchers to demonstrate the durability of historic materials.

Meanwhile, at the Construction Engineering Research Laboratory in Champaign, Illinois, the National Park Service has collaborated with the US Army Corps of Engineers on similar research.

Researchers read through construction manuals from the mid-nineteenth and early-twentieth centuries to put together everything from tongue-and-groove flooring to plastered brick walls. To simulate contaminated floodwater, the materials were dropped into water containing bacteria and mold.

The study may appear to be pointless in light of all of the older homes that still stand along the nation's coasts and rivers: many have survived multiple floods and still have their original floors and walls.

According to Pollard and Shackelford, lumber in older homes is more durable because it was harvested from trees that grew slowly over decades, if not centuries. That means the trees' growth rings were small and dense, making it difficult for water to penetrate. Furthermore, the timber was harvested from the innermost part of the trunk, which yields the hardest wood.

Plaster can also be water resistant, and common plaster coatings were made from lime, an antiseptic substance.

But here's the catch: flood insurance regulations in the United States frequently require structures in flood-prone areas to be repaired with flood-resistant products. Furthermore, many historic building materials have not been classified because they have not been tested.

Homes on the National Register of Historic Places, as well as some state and local registries, are exempt from the regulations in the United States. However, not everyone fully understands or is aware of the limited exceptions.

The far greater challenge, according to Pollard, is a lack of expertise among contractors and local officials. The regulations' interpretations can vary, especially in the aftermath of a major flood.

"You've got a distressed property owner," said Pollard, who co-owns a historic preservation firm. "They're dealing with a contractor who is being pulled in a thousand different directions." And the contractors are trained to dispose of all of that (wet) material as quickly as possible."

Karen Speights of Norfolk, Virginia, said a contractor replaced her original first floor, which was made of old-growth pine, with laminate flooring after her home flooded.

Speights' two-story craftsman was built in the 1920s in Chesterfield Heights, a predominantly Black neighborhood on the National Register of Historic Places. It is located along a Chesapeake Bay estuary in one of the most vulnerable cities to sea-level rise.

"I still believe I had a good contractor," Speights said, "but flooding was not his expertise." "You have no idea what you don't know."

According to Wolfe of the Florida Trust, there are thousands of historic structures along Florida's Gulf Coast. Many of them are wood-framed pier houses with plaster-and-lath walls.

Wolfe believes that many will simply need to be dried out after Ian. However, only a few local contractors are aware of what to do "in terms of slowly drying them and opening up the baseboards to get circular airflow."

Many contractors, according to Andy Apter, president-elect of the National Association of the Remodeling Industry, are unfamiliar with older building materials.

"I'm not aware of any course that teaches you directly how to work on historical homes," Apter, a Maryland contractor, said. "It's like a vintage car." You'll be limited in terms of where you can find parts and where you can find someone qualified to work on it."

According to Jenifer Eggleston, the National Park Service's chief of staff for cultural resources, partnerships, and science, interest in the resilience of older homes has grown since Hurricane Katrina, which deluged hundreds of thousands of historic structures along the Gulf Coast in 2005.

According to Eggleston, the park service recognized the growing need to protect older structures last year when it issued new guidelines for rehabilitating historic buildings in flood-prone areas.

When possible, the guidelines recommend preserving historic materials. However, due to a lack of research on flood resistance, they do not list specific materials.

That is where the research comes in.

According to Eggleston, a recent park service and Army Corps study discovered that some historic materials, such as old-growth heart pine and cypress flooring, performed significantly better than certain varieties of modern lumber.

Eggleston believes that after "clean water" damage, those floor assemblies could be dried and reused. However, they would almost certainly need to be refinished to remove "biological activity," such as mold and bacteria.

Pollard and Shackelford expressed hope for a change in practices that will save money for homeowners as well as taxpayers, who are frequently on the hook after a major disaster.

Meanwhile, more frequent rainstorms or stronger hurricanes will exacerbate flooding in historic areas, according to Chad Berginnis, executive director of the Association of State Floodplain Managers.

"Think about our country's historic settlement patterns," Berginnis said. "We settled near water on the coasts." We settled inland near water."