Our BatchGeo world MAP shows the locations of green architecture, green building and renewable energy projects featured on Solaripedia.
Poplar Forest is a retreat that Thomas Jefferson designed for himself near present-day Lynchburg, Virginia, in the early 1800s as a get-away from his busy life at Monticello. The octagonal home features passive design with integrated landscape design. Thomas Jefferson employed several passive design strategies for thermal comfort and daylighting in Poplar Forest. The home’s 12-inch thick exterior brick walls provide a mitigating thermal barrier to the hot summers in Virginia’s Piedmont region. The octagonal floor plan of the house creates a large middle room, surrounded by exterior rooms on all sides. This central space forms the Poplar Forest dining room, also the largest space in the house. As it has no exterior walls, and no windows, it utilizes a skylight that transverses the ceiling along and east/west axis to bring daylight to the space without bringing heat, creating a cool but light retreat. Exterior walls feature windows on multiple sides to capture breezes and facilitate cross-ventilation. Window side jambs are beveled to open more to the interior so that more sunlight is bounced into the rooms. Shutters on east and west windows can be opened or closed to block the sun or help seal in heat. The south portico has a generous roof covering large windows to provide a shade porch for summer, but allow plenty of light all year with views across the sunken lawn. Jefferson built the house over a basement that is earth-bermed to the north, with the lower south porch raised on Roman arches to shade the basement room from the summer sun. Because of the earth berm, the almost constant cooler air below allowed better food and wine storage in the basement. The east “wing of offices” that connects with the main house is also earth-bermed on the north, with a roof overhang along the entire south face that provides shade in summer, protection from weather, and allows winter sun to penetrate for daylighting. The partial underground structure also helped mitigate the heat from activities such as cooking and laundry, and storage of goods. The roof of the east wing was designed so that it could be used as a terrace, too, with a unique rainwater drainage system that shunted water toward the sunken lawn that slopes away from the house and towards gardens. Soil from the basement and wing excavations was mounded at the west and east ends of the home, and then planted with trees. These trees would have provided effective shading to the home when the sun was lower in the sky in fall and spring. There is a extant stand of giant poplar trees on the north side of the home. (Scroll down for additional resources)
Thomas Jefferson and his wife, Martha, inherited the plantation known as Poplar Forest from her father in 1773. The working tobacco farm of 4,812 acres eventually provided Jefferson with a significant portion of his cash income. The plantation also offered the perfect site for his most personal architectural achievement -- a unique octagonal house set within an elaborately designed landscape. In this meticulously planned retreat he had the seclusion to pursue his passion for reading, writing, studying, and gardening.
Poplar Forest, incorporates elements from ancient, Renaissance Palladian and 18th century French architecture, as well as British and Virginian design, fuse into a harmonious whole. The 16th century architect, Andrea Palladio, greatly influenced Jefferson’s plan for the revival of ancient Roman architecture and integration of landscape design into the architectural design.
The design of the house at Poplar Forest is highly idealistic in its elegant geometry. Its exterior walls form a perfect, equal-sided octagon. Inside, the space is divided into four elongated octagons surrounding a central square. The simplicity of the floor plan displays Jefferson's attraction to the precision of mathematics. The central space is a perfect cube, measuring twenty feet in all directions. With no exterior walls, it is lit from above: a sixteen-foot skylight streaks the room with exquisite light. This room supplies a soaring two-story space in what appears, from the front, to be a single-story house. Perhaps most important, the entire Poplar Forest retreat, house and landscape, radiates out from this elegant central space.
In classical architecture, a building’s proportions or room’s “order” determines the proportions and appearance of its columns, capitals, entablature, and decorative trim.
For the exterior of the house at Poplar Forest, the two octagonal privies, and the bedchambers inside the house, Jefferson used the Tuscan order. Tuscan columns and capitals are plain. The simplicity is meant to convey a sense of naturalness and integrity.
Adhering to the proper hierarchy, Jefferson used the Doric order in the central room—a more ornate decoration. For the room’s entablature he commissioned a sculptor to replicate an ancient frieze from the Roman Baths of Diocletian, alternating two elements: human faces, carved in low relief, and triglyphs, a “grill” of three vertical bars common to Doric friezes.
Jefferson broke the rules of neoclassical architecture, adding a third element, ox skulls, to the design. He explained to the confused sculptor, “You are right…those of the Baths of Diocletian are all human faces….But in my middle room at Poplar Forest I mean to mix the faces and ox-skulls.” In this private building, he felt he could follow his “fancy,” which, he wrote, “I can indulge in my own case, although in a public work I feel bound to follow authority strictly.”
For the parlor, Jefferson used the even more elegant Ionic order, commissioning his sculptor to replicate the entablature of the Roman temple of Fortuna Virilis. The delicate frieze consisted of small putti, or cherubs, alternating with ox skulls, connected by swags of foliage.
Among Jefferson’s earliest architectural sketches, made when he was in his twenties, is a plan for a freestanding octagonal chapel. He based his design on Andrea Palladio’s round Temple of Vesta, transforming it into an octagonal from using a prototype from an 18th century British book. This represents an early example of Jefferson’s lifelong tendency to create something original from two or more prototypes.
The geometry of octagons appealed to Jefferson’s mathematical mind. There was a practical reason too: octagonal rooms, studded with large windows, create light-filled interior spaces. The residence at Poplar Forest was Jefferson’s ultimate octagon: the only fully octagonal building he ever constructed and one of the first octagonal homes in America. Even two privies are octagonal, symmetrically flanking the main house to the east and west. Jefferson designed these domed necessaries using the same rules of architectural proportion as the main house, with restorations that include chestnut shingle roof, louvered lunette windows, door, and stairs, with a child's seat installed after Jefferson's time.
Jefferson adopted many aspects of the house’s interior design from buildings he had seen in France. He especially liked the light-filled interiors there, and both the skylight in the dining room and the floor-to-ceiling windows in the parlor are French touches. Jefferson filled the south wall with triple-sash windows: when the bottom two portions are raised the window opening serves as a doorway to the porch. Jefferson often read in this south-facing room, which would have been flooded with light.
In each of the large bedchambers, Jefferson’s workmen installed “alcove beds,” which Jefferson felt saved space. An indoor privy—or toilet—was tucked away beneath the stairwell next to Jefferson’s bedchamber, an unusual convenience for the time.
One important aspect of the exterior was also influenced by French architecture. Jefferson had observed that “all of the new and good houses” in Paris were of a single story. He designed the house Poplar Forest to be built into the crown of a hill, so that his two-story house would appear to be a single story from the front.
For all his love of geometry and classicism, Jefferson yielded to practical concerns at Poplar Forest. In 1806, after construction of the house had just begun, he added two porches, two stair pavilions, and six doorways. Although they compromised his perfect octagon, it is easy to understand why Jefferson made these changes.
The front (north) porch—called a portico in the vocabulary of classical architecture—protected the entrance during bad weather and gave the house a neoclassical look. The rear (south) portico provided an ideal spot to view the lawn and countryside beyond.
Jefferson disliked staircases because he believed they wasted space. Without them, however, anyone walking between the upper and lower floors would have had to go outside. Even with the addition of internal stairs, anyone moving from the lower level to the main floor would have entered one of the bedchambers, underscoring the informality of Jefferson’s retreat.
From heavy timber frame construction, to hemp sash cord custom-made in Holland, and iron hardware wrought at Colonial Williamsburg, the details and materials have been carefully and faithfully reproduced as the building is restored in a Jeffersonian era way. Details and materials, such as lumber, glass, lead, hardware, bricks, mortar, paint and finishes are carefully researched for site specific correctness and executed with accurate historical precision, even to the point of reviving a few “lost art” techniques such as column rendering and burning limestone for the production of traditional lime mortar and plaster. A conscious decision to have the restoration follow Jefferson’s historical sequence of finishing the house makes the interpretive process unique among museums.
The Poplar Forest Octagon and Key Meridians
There are some theories that Thomas Jefferson designed the octagonal Poplar Forest estate to conform to Key Lines that mark other important structures in the US and world. It has been suggested by author Louis Buff Parry that Jefferson may have been a Knights Templar Strict Observance, American Rite - a designation of German Masonry that descended from Prussian Royalty – and that his key lines are designed to highlight a sort of “holy grail” of information or philosophy. Jefferson built his octagonal Axis Mundi as a small private residence using his own private funds and not as an imperial axis as his forebears had. Jefferson oriented Poplar Forest so that one of the facets of his home creates an azimuth or key line that points to several other structures he designed or built, including Monticello, the University of Virginia campus, the Barboursville Mansion, Montpelier (James Madison’s home named for the Capitol of the Languedoc), and Washington D.C. Others would later add the Georgia Guidestones to this alignment as well as the towns of Madison and Monticello, Georgia. This same azimuth of Poplar Forest on the globe extends to Europe, crossing the region of Germany known as Prussia. Charlottesville, Virginia, Jefferson’s hometown near Monticello, was named in 1762 for Queen Charlotte of England who was originally from Hanover, Germany. The actual structure of Monticello is located only about a hundred yards from the exact 38th parallel. Some ancient places may have been meant to mark prime meridians that were established by local rulers. Jefferson seems to have been influenced by this tradition. This fits the assumption from the book of the Holy Grail that he was a Knights Templar Strict Observance. He created his home Poplar Forest as an Axis Mundi. He created alignments of architecture that are still being added to today as evidenced by the Georgia Guidestones.