When A Master Work Fails: Three Case Studies

Some of the greatest restoration challenges arise when historically significant works weather, degrade, are neglected, or simply have suffered through inappropriate renovations. Restoration strategies are compounded when original historic materials, either natural materials like wood or stone, or production processes are no longer available. And when the failure is due to improper design or inadequate construction methods, corrective restoration methods may alter or compromise the original design intent. The following three case studies illustrate restoration philosophies based on balancing preservation, resolving the underlying building deficiencies, and introducing “thoughtful change” in protecting significant local structures for future generations.

Case Study 1

John Yeon’s 1948 Portland Visitors Center was designed as an exhibition showroom with large open spaces, a pinwheel plan, on a highway dividing median, accessible by car, and constructed of standardized wood framing components including recently developed experimental plywood. When the highway was replaced with a riverfront park and the Visitor Center programming was relocated, the singular purpose building became obsolete resulting in a number of incompatible conversions including substantial alteration of the main gallery space to an industrial kitchen. Contributing to the slow demise was the degradation of the exterior wood components and failure of the plywood as a result of the northwest climate and inadequate weather protection. By the time the Friends of John Yeon and the City of Portland Water Bureau invested resources into the restoration, the Visitor Center had lost or compromised 80% of its historic interior finishes and the exterior façade had been heavily altered. However, the original floor plan, massing, scale, exterior spaces, and essence of Yeon’s modular design and sense of place remained. The restoration approach focused on preserving these significant design elements while providing flexibility of interior layout.

Space programming respected the historic floor plan and scale of the original structure and recreated Yeon’s original design intent of integrating indoor space with outdoor space. Extraneous equipment and unsympathetic additions were removed from both the interior and exterior. Interior design elements, furniture, and fixtures maintain the open gallery spacial quality while integrating new furniture and fixtures meeting the needs of the tenant. Major preservation focused on the exterior restoring original paint colors through serration studies, restoring building signage in original type style and design, preserving original wood windows, when present, and restoring the intimate courtyard with a restored operating water feature.

Case Study 2

Moore, Lyndon, Turnbull & Whitaker’s 1965 Pavilion at Lawrence Halprin’s Lovejoy Fountain is a whimsical all wood structure with a copper shingle roof. Although a small structure, the pavilion represents a major mid-transitional work for Charles Moore as his design style moved from mid-century modern to Post-modern design. In keeping with the naturalistic design aesthetic established by Halprin, northwest wood species comprise the major structural system including the roof trusses, vertical post supports, and vertical cribs built from 2 x 4 members laid on their side and stacked.

Vertical loads are transferred from the trusses to the wood posts and spread to the wood cribs. Under the point loading, the cribs have compressed resulting in a sag or lean in the roof structure. Since the 2 x 4 wood members have crushed, they cannot be restored or salvaged as part of the restoration effort so new members were designed to replace the historic material.

The restoration approach is intended to correct the structural deficiencies and replace the failed members with no changes to the historic appearance of the structure. The crib design allows for insertion of new steel elements, invisible from the exterior, capable of providing additional support for vertical loads. The difficulty arises because standard wood products available today have different visible and strength attributes from standard components available in 1965. Sourcing appropriate lumber is dependent upon clear and quantifiable specification, high quality inspection, and visual qualities. There are no structural standards for reclaimed or

recycled lumber compounding the incorporation of “old growth” lumber as part of a new structural system. When original source material is no longer available, best practices for narrowing the selection of new materials will of necessity be combined with subjective visual qualities and a best-guess scenario as to how the new material will age in place similarly to the historic material. There are no single solutions so experience is key.

Case Study 3

Whether or not Michael Graves’ Portland Building is considered a master work is greatly debated. Never the less, the building was nominated to the National Register of Historic Places after only 30 years and is recognizable around the world as THE building representing the start of Post Modernism. There is no debate to the fact that the building leaks. However, the method of building envelope repair could dramatically or minimally impact the exterior character defining features.

The façade of the Portland Building incorporates standardized aluminum single unit windows, aluminum windows ganged together to form a curtain wall, ceramic tile, and stucco veneer as the prominent construction materials. All of these systems or individual components are neither produced nor assembled currently in similar manners due to improvements in technology and building envelope science.

Proposals to improve envelop performance of both the individual window units and window systems are challenged in finding products that will both improve performance and retain the aesthetics of a Post Modern building. (i.e. retain the essence of criticism towards Post Modernism by preserving the appearance of insubstantial material installed as a thin veneer). Windows have always been a source of controversy in preservation and now the definition of windows has expanded to include curtain wall systems as the importance of preserving Recent Past and Modernism has entered into the mainstream.

 

When a structure, like the Portland Building, relies heavily on the expression of its skin as the character defining feature, off the shelf solutions for fixing envelop deficiencies must be expanded to include customization, façade impact studies, robust strategies for solving the issue, and out-of-the-box thinking by conservators, architects, historic consultants, and building envelope experts. A collaborative approach based on the original architect’s design intent must drive the decision making. It is an unusual approach, but original design intent will be a key factor when resolving façade problems on Modern and Post Modern structures.

Burnt Clay Facades

Terra cotta, or “burnt clay,” is a hard baked, high grade of weathered or aged clay. It is similar to brick but the clay is of higher quality and fired at higher temperatures. This article focuses on exterior architectural terra cotta as distinguished from statuary, pottery , and terra cotta blocks used as inner wythes of wall or fill material.

The 1893 Columbian Exposition in Chicago demonstrated the versatility and ornamental qualities of terra cotta.* It highlighted the great variance in color and shapes possible with terra cotta and began the demand in the United States for terra cotta that lasted through the late 1930s. Terra cotta is prized for its light weight, longevity, aesthetic qualities, and unit construction. At the peak of production, almost every urban area in America was producing architectural terra cotta in some variation. Today, most replacement units are produced by either Gladding McBean or Boston Valley Terra Cotta.

Specific forming techniques including hand press, machine press, slip casting, and extrusion are used depending on the shape and style of unit required. In the analysis of terra cotta failure the forming techniques are less critical than the strength characteristics of the fired clay, the integrity of the exterior surfaces, and structural support systems.

Exterior ornamental terra cotta was marketed as a light weight water proof cladding. If proper construction techniques were employed, and the system was maintained, and the local climates were mild, terra cotta performed as sold. However, terra cotta adorns buildings in severe weather climates, and is installed with structural materials affected by environmental conditions, and located on façade elements inaccessible for routine maintenance.

The mortar joints are the material most susceptible to failure. Joints often exist on all three axis with some units of terra cotta designed for flat horizontal surfaces. Over time and exposure, the mortar fails providing a means for water intrusion. Sever cycling of weather in simultaneous freeze/thaw conditions can cause the terra cotta clay to expand and contract, accelerating the crazing or cracking of the protective glaze. Extensive crazing can lead to glaze spalling and allow for further water intrusion.

Once water enters the system there is no weep path allowing for water egress. Construction means and methods, as well as the cellular unit design, trap water and contribute to the potential corrosion of steel lintels, wire ties, steel structural support members, and other miscellaneous metals. Rapid freezing and thawing cycles, in addition to steel corrosion, can crack terra cotta units. If the units remain unrepaired, further water intrusion and/or absorption will occur.

 The repair of terra cotta will depend both on the cause and manifestation of the defect. Typical defects include crazing of the glazed finish, shallow surface spalls, deep spalls affecting the bisque, cracked units, inadequate support and / or anchorage, corrosion induced stress fractures, impact damage, mortar degradation, lack of maintenance, and inadequate repairs.

Proper terra cotta repair methods are linked to the cause of defect. Repair techniques are often performed on-site by skilled tradesmen. When damage to the terra cotta unit is severe, full replacement may be required. Defects due to inadequate support or a result of corrosion to supporting steel members is likely to require more invasive repair strategies including removal and replacement of several courses of interlocked terra cotta units.

When replacement units are not required and the scope is limited to on-site repair, labor costs exceed material costs. Since many historic terra cotta units were specialty designed and installed for the structure, a premium price is paid for replacement. New exterior decorative terra cotta is available only from the sources referenced and with small quantity orders, the first unit is approximately $5,000 with much of the costs attributed to making the form and determining the finish color and texture. Subsequent costs per unit will decrease with the range of decrease dependent upon quantities required.

The most important component of terra cotta repair is an understanding the cause of deterioration and the proper repair specifications. Both are derived after a full condition assessment and evaluation of the existing conditions.

Sources

·         First two images from Wikipedia; others property of PMA

·         Last of the Handmade Buildings, Virginia Guest Ferriday, Mark Publishing Co., Portland, OR 1984

·         National Park Service, Preservation Brief No7, Preservation of Glazed Terra Cotta

·         APT Pacific NW Chapter 2005 workshop

·         Terra Cotta, Standard Construction, Revised Ed., National Terra Cotta Society, 1927

Super-Sized Historic Structures: A Preservation Dilemma

The Blimp Hangar, Naval Air Station Tillamook

Without considerable effort, the Guinness Book of World Records’ largest wooden structure, and the most extant naval air station from World War II is in danger of disappearing. 

Commissioned in 1942 and operational through 1949, the Naval Air Station Tillamook (NAS) is a 1,600 acre site comprised of buildings, structures, landscape features, as well as a current active runway. A smaller 400 acre site has been designated an eligible historic district. The original use by the NAS Tillamook contained 32 defense, eight industrial, five government, four transportation, three commercial, three agricultural, three residential, two recreation and culture, one education, and one utilitarian structures, plus one cemetery. The most significant structures include the airfield, Hangars A & B, ammunition magazines, and structures that supported the operation of the Naval Air Station. Many of the buildings may be the only remaining example of their kind. Much of the site is still operational:  the roads, sidewalks, water power sewer and utility lines, as well as the railroad infrastructure were constructed by the US Navy remain on site and are character defining features.

Hangars A & B were built for “K type” dirigibles that are steerable, non-rigid, lighter than air aircraft used for naval air patrol of enemy submarines. During World War II, the hangars served as mooring and maintenance sites for two squadrons of dirigibles that patrolled the coast line from the Strait of Juan de Fuca to California. A fire in 1992 destroyed Hangar A. The remaining U.S. Naval Air Station Dirigible Hangar B, is the world’s largest wooden clear-span structure measuring ¼ mile long and 23 stories in height. Its construction technique is considered both resourceful for war time efforts and an innovative structural solution. Incredibly, the hangar was
completed in just 90 days.

Hangar B reflects the unique challenges associated with super-sized historic properties. Monumental historic properties pose significant management, maintenance, and financial challenges to the long-term stewardship of such properties. Aging infrastructure, 70 or more years of service-life, and limited lease markets for using enormous structures increasingly place pressures on the decisions to retain the resources. Despite the desire to be good stewards, large properties rarely generate sufficient funding to go beyond very basic emergency and/or minor piece meal repairs. Straight forward maintenance items, like new roofing or painting, can cost several million dollars.

Creative, multi-jurisdictional, community involvement, private/public partnerships, government programs, and national and international marketing campaigns have become key elements to long range cultural resource management plans. The unique structures require innovative solutions matching the monumental character and commanding presence. Success stories abound from the saving of West Baden Springs Hotel in French Lick, Indiana to Centennial Hall in Wroclaw, Poland. The efforts to retain the giant structures are well deserved, because the continued loss of such buildings diminishes our understanding of world events. 

Peter Meijer Architect, PC has been engaged by the Port of Tillamook Bay since 2005 to provide a wide range of preservation related services regarding Naval Air Station Tillamook; Historic photos from the Tillamook County Historical Museum.