Unprotected modernist houses are at risk of demolition as land often holds greater value than architectural heritage, says conservation group Docomomo US in response to actor Chris Pratt tearing down a home by architect Craig Ellwood.

Pratt and his wife Katherine Schwarzenegger drew attention online when news broke that the couple had begun work on a 15,000-square-foot home in place of the Zimmerman House by Ellwood, who designed buildings in Los Angeles from the early 1950s to the mid-1970s.

Located in the Brentwood area, across the street from a house owned by Schwarzenegger's mother, the Zimmerman House was completed in 1950 and was one of Ellwood's earliest projects.

It was demolished by Pratt and Schwarzenegger, who wanted to make use of the land for a sprawling mansion.

Docomomo US executive director Liz Waytkus claims the demolition of the mid-century home is part of a wider issue of sought-after land and location taking priority over the significance of historic homes.

"The problem is systemic," she told Dezeen. "Older mid-century homes are smaller and underbuilt for their plots of land."

"The land has become more valuable than the house, and even if people understand the value of such a home, location and land value often trump architectural significance."

The Zimmerman House was a one-storey home with original landscaping by Garrett Eckbo, which was also destroyed in the demolition.

The house was sold to Pratt at the end of last year. In a video taken at the home's estate sale in 2020, which was recently shared on Tiktok, its structure and original fixtures appeared to be in good condition.

Waytkus likened the Zimmerman House demolition to the loss of the Geller I house in Long Island by modernist architect Marcel Breuer, which was torn down in January 2022.

She stressed that Docomomo US works to educate people on the history of homes like these, striving for the best outcomes for historic homes without treading on individual private property rights.

The group is currently working with the Southampton Village Board of Architectural Review and Historic Preservation on the protection of five homes in Southampton, Long Island, including a 1979 house designed by architect Norman Jaffe, which the original owner plans to demolish.

Waytkus expressed that conversations with property owners are important to protect the legacy of historic homes and at the very least, have them properly documented.

"We are reasonable people and would have appreciated the property owners having a conversation with community leaders such as Docomomo US/SoCal and the Los Angeles Conservancy in [the Zimmerman House] case, before pulling the demolition permit," Waytkus said.

"At a minimum, some elements could have been retained or reused and the property should have been documented."

"The homeowners also could have avoided this negative publicity by extending the opportunity for communication and collaboration with our community," she added. "We are always open to having those conversations."

Non-profit preservation group Los Angeles Conservancy flagged the planned demolition of the Zimmerman House in January, but no protections were made.

In 2022, Waytkus wrote that the demolition of Breuer's Geller I house should be a wake-up call to protect modern buildings, which was followed up by Docomomo's selection of 11 significant 20th-century buildings at risk of demolition in the US.

The photography is by Julius Shulman via Paul Getty Trust, Getty Research Institute, Los Angeles.