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The Patina Of Age

By Hadiya Strasberg; originally published in Period Homes





Project: Gamble House, Pasadena, CA
Architect: Kelly Sutherlin McLeod Architecture Inc., Long Beach, CA; Kelly Sutherlin McLeod, AIA, project architect
Restoration Consultant: Historic Resources Group, Hollywood, CA; Peyton Hall, AIA, principal
Conservator: Griswold Conservation Associates, Beverly Hills, CA; John Griswold, principal
General Contractor: Voss Industries, Inc., Pasadena, CA; Jeff Voss, president

The conservation of Greene & Greene’s famed Gamble House in Pasadena, CA, was concerned mainly with exterior wood elements. More than a dozen wood species can be found in this home. Oak, redwood, Douglas fir, teak, cedar and other species were formed into timber beams, rafter tails, wall shakes and interior elements. After decades of exposure to the natural elements, though, much of the exterior woodwork had deteriorated. Previous repairs using impermeable epoxy putty also compounded the damage to the rafter tails, outriggers and beam ends of the National Historic Landmark building.

Built in 1908 and 1909, the 8,100-sq.ft. house was, in many ways, the apotheosis of Greene & Greene’s design sensibility. This sensibility emphasized detail and handmade, custom-crafted elements. Greene & Greene designed every aspect of the house, including the furnishings, light fixtures, windows and landscaping. Local craftspeople fabricated furniture, wood carvings, leaded and stained glass and other elements.

Fortunately, all of the interior treasures have survived. By the 1990s, however, the exterior of the house required extensive repair and conservation. The owners — the City of Pasadena and the University of Southern California — believed it was imperative to conserve the Gamble House and embarked on fundraising, grant writing and assembling a restoration team.

In 2000, Historic Resources Group (HRG) of Hollywood, CA, completed a Historic Structure Report and developed a conservation plan. The 600-page assessment became the guiding document for the subsequent conservation of the exterior.

HRG, along with restoration architect Kelly Sutherlin McLeod Architecture Inc., Long Beach, CA, and conservator Griswold Conservation Associates, Beverly Hills, CA, subscribed to a philosophy that the house should receive all necessary repairs without taking on the appearance of new construction. This was adopted from the Secretary of the Interior’s Standards for Historic Properties and from the Code of Ethics and Guidelines for Practice of the American Institute for the Conservation of Historic and Artistic Works. All agreed that “the exterior needed to resonate with the Greene’s original design vision,” McLeod says.

In October 2003, scaffolding was erected, allowing the architects and contractor access to the beams and rafter tails. As all of the work concentrated on the exterior of the house, barring minor electrical work, the Gamble House remained open for tours. Because of this, the scaffolding, security fence and office trailer were painted a custom chocolate brown so that they would blend in with the house and its surroundings.

More than 250 Douglas fir rafter tails and beam ends required attention due to rot beneath the surface. “The old patching material had formed an impenetrable barrier at the surface of the wood, preventing moisture from escaping,” says John Griswold, principal of Griswold Conservation Associates. Dental tools and other hand-held instruments were used to remove the old material and the fragmented wood was treated with various consistencies of fungicide and Abatron’s LiquidWood epoxy consolidant. “In the case of severe deterioration or where structural integrity was compromised, we replaced missing wood with Abatron’s WoodEpox,” Griswold says. “The lightweight epoxy putty was engineered to have closely compatible properties with the wood, such as thermal expansion and moisture permeability.” Physical properties were also mimicked. To obtain the appearance of the Douglas fir, original grain patterns were simulated. As the wood ages, the epoxy patches will split and form end-grain checking similarly. “Each patch ended up being almost a portrait of the wood that was lost,” says Griswold.

All of the woodwork, including the rafters and beams, was finished with Amteco TWP-500 series penetrating sealer, an alkyd-modified long oil with UV stabilizers. Griswold explains, “Experts at the Forest Products Laboratory of the National Parks Service recommended this product, which we tested along with other possible consolidants for the redwood wall shakes. We found it to be very good for the other wood elements, as well.”

The 36-in. split redwood shakes were found in varying degrees of deterioration. “Thirteen different conditions were identified,” says Edward Bosley, director of the Gamble House, “from diseased bare wood to sound material with perfectly bonded paint.” Though 70-year-old lead-based degraded paint covered the shakes, research and testing indicated that stripping the paint “would result in the loss of surface detail of the split-grain texture,” Griswold says. “As it turns out, the 1930s paint color was not too far from the color of pigment suspended in the original creosote stain, so we developed a strategy to preserve the paint while returning the dark-greenish color of the shakes.” The 1930s painting had been directed by the last family resident of the house, most likely due to soiled and degraded shakes that had turned darker, according to historic photographs. Several layers of TWP 500 consolidant were used to saturate the color of the new paint job after the shakes were individually cleaned.

Another issue in the treatment of the shakes and the remainder of the house was that the consultants and architects wanted to preserve as much of the original historic fabric of the house as possible and to retain its patina of age. “We did not want to restore the house to its original 1908 appearance,” Griswold says. “This would have resulted in a loss of authenticity.” McLeod adds, “In determining what the house would look like after 95 years without repairs and in good condition, we had to factor in the age of the house, the nature of the materials, original colors and textures, aging and weathering patterns, while honoring the Greene’s original design intent.” In keeping with this philosophy and to preserve historic evidence, only about 28 seriously damaged shakes were replaced with nearly identical salvaged vintage shakes; some of the more hidden shakes weren’t even treated. Similarly, scratches, holes and marks that could allow moisture to escape were intentionally made on the new rafter tails and beams.

The leaky roof was replaced to ensure protection of the interior. Approximately the fourth generation of roofing applied to the house, it had begun to fail and look objectionable soon after installation. “The asphalt bed holding the granules had cracked and slumped in the heat,” Griswold explains. No original roofing scraps were uncovered, but early records stated that the 1908 roof was a Malthoid roof, a rolled membrane with adhered granules. To replicate this, modified bituminous built-up composition roofing was used. “A roofing material was selected that closely represented the color and texture of that originally selected by the Greenes – a material no longer available and that failed within the first 10 years after installation,” McLeod says. “The challenge was that the modern material, although technically superior, didn’t naturally roll around the eave. To achieve the desired effect, the roofing material was loosely wrapped without solidly adhering it around the eave in order to prevent further damage to the historic substructure inflicted by previous roofing campaigns.” To restore the roof profile to its original look, a large HVAC hood and several small vents were removed. Minor repairs were also made to downspouts, and new roof flashing and gutter drain screens were fabricated and installed in some places.

Many of the teak, mahogany, fir and cedar window frames and doors were deteriorating, so dirt, paint and varnish were removed and the wood was treated with the Amteco sealer. Window screens were found in even worse shape, so they, too, were removed for repair. “They were very fragile and dilapidated from exposure and use,” says Griswold. “We were able to return all of them to good working order without replacing original material with new wood.” Non-original finishes were stripped and the non-historic nylon screen fabric was replaced with bronze-wire screens. Aiding in the repair of the damaged screens were 11 unused screens found in basement storage, screens that had never been installed on the house. “We were able to get a glimpse of the original screen fabric material and the finish,” says Griswold. These screens were later returned to archival storage.

Another part of the project involved the restoration of the wood railings around the sleeping porches. Weathering and dirt had taken their toll, and the railings needed to be cleaned, stripped and then finished with an oil-based preservative. “Once treated, beautiful grain figure emerged where surfaces had only appeared black before,” says Griswold.

After repairs on the main house were completed, the deteriorated rafter tails, windows, doors and shakes of the single-story garage, which serves as the Gamble House bookstore, were treated. The roof was also replaced.

In August 2004, the first comprehensive conservation to be undertaken on the Gamble House was completed on budget and on schedule. The most gratifying aspect, McLeod says, “was the honor of contributing to and participating in the conservation of a valuable national treasure.” ♦