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What began with fixing a leaking pipe turned into a forensic exploration of the bones of the Branch Museum of Architecture and Design, designed as a mansion by John Russell Pope for the Branch family.  Even though the plumbing system is nearing the end of its life, the structure of the house was built to survive the fires that occurred throughout Richmond’s history. University Circle, historically the domain of UVA professors, was roofed with ordinary asphalt shingles, but the hips and overhangs were softly curved, lending the house a very distinctive appearance in this otherwise safely Jeffersonian Charlottesville neighborhood.

Glavé & Holmes’ work at the Branch House included replacement strategies for the 102-year-old plumbing lines.  It was more challenging than expected because the building’s construction consists of concrete floor slabs and Pyrobar (gypsum block) walls.  This meant that it was very difficult to trace and replace pipes, but was informative as to fireproof construction strategies in the early twentieth century.

Branch House Structural Framing Plan (December 1916).

Part of the drawing set from John Russell Pope’s office, dated 1916, included structural drawings by the Fireproof Contractors Corporation in New York City.  This showed that the house’s fireproof design was deliberate in the early design phase of the project.  It appears construction followed the design specifications to protect the building from fire, which consists of concrete slabs supported by the brick exterior and central internal bearing walls with some steel beams and columns where needed for longer spans. Walter Dotts of the Old House Authority, and a direct descendent of John Kerr and Beulah Gould Branch, suspects a massive fire at Richmond’s Jefferson Hotel in 1901 factored significantly in the decision to make the house fireproof, as well as Richmond’s rather strict fire protection building practices at the time. 

While building with concrete dates back at least to the ancient Romans, it did not become a common commercial building material until the latter part of the 19th century when engineers experimented with reinforced concrete – in which iron and, later, steel rods embedded in the concrete helped with tensile forces in spans.  The building industry was not only interested in the novelty of reinforced concrete at the start of the 20th century but in finding ways to make it affordable by reducing the cost of on-site building of formwork.  The Branch’s slab design included one of these products, a metal tile [i.e. pan] system that is a forerunner to today’s steel decking for concrete slabs.  After researching several textbooks printed between 1900 and 1915 on common construction techniques and concrete design for buildings, G&HA architectural historian Fred Esenwein was able to decipher the structural drawings and trace the manufacturer of the metal tiles to the General Fireproofing Company based in Youngstown, Ohio.

To maintain a highly protected building, the non-structural partition walls are made of a fire-resistant material called Pyrobar, first identified by the project’s contractor Daniel & Company.  It was a product made by the U.S. Gypsum Company starting in 1903 as an alternative to terra cotta tile and in production until the 1960s when drywall became a dominate material with tested fire-resistance.  The name is likely a hybrid of pyro meaning “fire” and bar shorten from “barrier.” It is a hollowed-out molded block and looks similar to concrete block except it is about twice the size as standard concrete block and the primary material is gypsum instead of cement.  The block faces have a wavy surface so that plaster can be applied directly to the blocks.  It is usually found in buildings requiring stringent fire protection, such as civic buildings such as schools and courthouses, and less commonly found in residential construction. 

As fascinating as this construction is as a history of building technology, it has posed challenges in efforts to determine the locations of pipes, because pipes have been discovered embedded in the Pyobar walls and are possibly embedded in parts of the concrete floor slabs.  Selective demolition in this construction system also poses higher risk to damaging historic finish materials such as ornamental plaster ceilings and ceramic tile walls.  The approach has been to incrementally introduce new plumbing lines concealed where cavities exist between the slab and finished ceiling or to route the pipes exposed in service areas out of public view, which has been done dating back to the 1919 construction of the house.  Having to work around the 1919 fireproof construction gives new meaning to the phrase “they don’t build ‘em like they used to.”

Underside of the concrete floors at the Branch Museum.  The ribbing comes from the steel tile formwork. 
Cross-section of a Pyrobar block with plaster applied directly to the outside face. 
The Brody Jewish Student Center was completed in 2019 with a dimensional asphalt roof simulating the bent cedar shingles.

Pyrobar from US Gypsum Company brochure, 1919.
Inside the ceiling cavity at the Branch House.  Many GF Steel Tiles remain in place (brown surfaces).  The white Pyrobar wall is visible at the lower portion of the image; note the wavy lines on the surface for plaster adhesion.  Both materials were common fireproofing assemblies in the early 20th century.