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Stoneleigh Estate - Renovations of The Main House
Publication Date
February 25th 2019

Maintaining a Historic Perspective

Renovations to the Stoneleigh Estate’s Main House on Philadelphia’s Main Line provided modern upgrades while being sensitive to the home’s classic aesthetic


In 2016, the Haas family donated the historic Main House and 42-acre Stoneleigh Estate, in Villanova, PA, to Natural Lands for conversion to a public garden. Opened in 2018, Stoneleigh: a natural garden — which preserves designs from the Olmsted Brothers, sons of the famed Frederick Law Olmsted — is a stunning reflection of more than a century of horticultural conservancy.

“Since my first visit about 20 years ago, I have always loved Stoneleigh,” said Jane Pepper, a member of Natural Lands’ Board of Trustees and former president of the Pennsylvania Horticultural Society, in a statement. “The stately trees, the wide expanses of lawn, and the elegant architectural features make this a special place, and I’m so grateful to the Haas family for making it available for future generations to enjoy.”

“The stately trees, the wide expanses of lawn, and the elegant architectural features make this a special place, and I’m so grateful to the Haas family for making it available for future generations to enjoy.”
- Jane Pepper

The design team’s goal for Stoneleigh’s Main House was to repurpose the historical building to accommodate the institutional headquarters for the Organ Historical Society and house a vintage organ (circa 1931) relocated from West Orange, NJ. Renovations encompassed office spaces, a library, an organ pipe chamber, and archival spaces for the Society along with administrative spaces for Natural Lands and a new commercial kitchen and catering area for events.


Stoneleigh Estate Main House Back

Uniting Nature and Music

The design team needed to accommodate the installation of a 1931 pipe organ for the resident Organ Historical Society. The Aeolian-Skinner Opus 878 serves as a lynchpin for the renovation’s plan to unite nature and music, as desired by the Haas family. The organ’s 2,218 pipes were installed in the basement, allowing the pipes’ bellows to be heard throughout openings in the floor as the organ is played in a room off the house’s foyer. Older basements are less-than-ideal environments for such a sensitive instrument due to damp and cold conditions, so extra care had to be provided in the design.

Stoneleigh Estate Inside Lighting

Stoneleigh Estate Inside Lighting2

stoneleigh estate inside lighting3

stoneleigh estate organ room

Modern Systems / Historic Aesthetic

Installing modern HVAC systems was vital to preserving the building’s interior. The challenge was providing this modern amenity without compromising the Main House’s historical integrity. A thoughtful and sensitive approach led to the installation of archival-level climate control HVAC systems. Non-invasive mechanical system distributions were designed to conceal and minimize interior disturbances. This approach provided modern standards while preserving historic decor and aesthetics.

For critical areas, such as historic archival spaces and the rare books library, the unique HVAC systems provide precision cooling, heating, and humidity control. A new interior envelope with continuous vapor barriers and gasket doors also helps maintain the desired temperature and relative humidity to a tight tolerance, as required by museum and archival standards. Each space was designed as an independent zone with its own air handling unit and space controls, including thermostat, humidistat, monitoring, and fault alarms.

Lighting and electrical systems were also designed to minimize impacts to historical features. For example, specialty lighting, with lighting controls, was installed in spaces with historic appeal on the ground floor, while general illumination design was provided for other spaces. To help conceal the new electrical service required to support the property and garden upgrades, a garage was transformed into an electrical space with electrical panels, switch gears, transfer switches, and a back-up outdoor generator. Fire alarm systems, audio/visual, telephone/data, security, and site power/lighting systems were also installed.

An important part of Stoneleigh’s renovation was the facility’s new fire protection systems. Having so many historical elements, it was important that the Main House’s new design be sensitive to its interiors. A new fire protection system encompasses the entire house, without encroaching on points of visual interest. For example, a wet system with detailed pipe routing serves all non-critical spaces, with concealed sprinkler heads serving areas with original decorative ceilings and moldings. Critical areas, such as historical archival spaces and the organ pipe chamber, are served by a dry or non-water based FM-200 fire suppression system. A new fire pump provides the required flow and pressure for the new fire protection systems. The fire protection system is critical to safety of the Main House, which will be used for events.


Exemplary Historic Preservation

Stoneleigh: a natural garden is now open to visitors, free of charge. Thanks to the careful renovations by the design team, which included John Milner Architects, and Urban — who provided mechanical, electrical, plumbing and fire protection engineering services — patrons can experience the property’s historic cultural value.

“Stoneleigh is unique among our preserves in so many ways,” said Molly Morrison, former president of Natural Lands, to the PhillyVoice. “We envision a place where the public will be able to enjoy the quiet and beauty of the Stoneleigh grounds and be motivated to learn about the joys and benefits of gardens that emphasize the use of native plants. We are deeply honored to be entrusted to carry on the Haas family’s legacy of stewardship for this magical place, and excited beyond measure to add Stoneleigh as a unique, shining star in our constellation of preserves."


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