Tag Archives: restoration

Inherent Sustainability of Historic Architecture

Trinty-Episcopal-Church-pmapdx

The terms ‘Sustainability’, ‘Green Building’, ‘Environmental Design’, and other similar phrases have recently become critical in how we approach and understand contemporary architecture. As concerns over pollution, global warming, and our impact on the surrounding environment have gained traction – we have begun to understand the building industry’s contribution to these issues. The US Green Building Council reports that buildings account for 39% of all carbon emissions in the United States, surpassing both industry and transportation.

At the core of the issue is how architects, clients, and the public imagine buildings should function and operate; a vision which has transformed over the last two centuries as technological advances have developed the capabilities of the building industry. In the last two centuries, buildings have become monuments to the Industrial and Technological Revolutions. The development of electrification, central heating, air conditioning, steel and concrete have transformed how architects design and how users function within the built environment. This shift has transformed architecture from an inherently sustainable practice into a much more complex and often unresponsive process.

While the phrase ‘sustainability’ has only recently been associated with architecture, many historic buildings were designed by incorporating sustainable practices. Without electricity, buildings by necessity had to respond to site orientation and the local climate. Natural ventilation was used to passively cool buildings, well placed windows provided natural light, and construction methods varied by location to provide an appropriate level of protection from the surrounding environment. However, as a result of modern renovations, these sustainable attributes are not always utilized to their fullest potential.

Historically, large, operable windows were an integral component of architecture in moderate climates like the Pacific Northwest. The glazing provided natural daylight while the operability allowed users to ventilate spaces based on thermal comfort. Today, the operability of windows in many historic buildings has been compromised for a variety of reasons:

• Windows that have been fixed shut to prevent users from overriding the central air system.
• Broken window hardware that hasn’t been properly maintained.
• Windows that have been painted shut.
• Windows that have been fixed shut to minimize maintenance.

Without the natural ventilation that was incorporated into the original design, these historic structures often overheat and/or rely heavily on central air conditioning. One must question why the inherent sustainability of these historic structures was compromised. Was it simply our initial infatuation with mechanical heating/cooling systems? As passive sustainable design gains traction it is critical that we understand the capabilities of historic structures in regards to their inherent sustainability.

For further investigation we have identified a case study that explores the possible impact reintegrating natural ventilation may have on thermal comfort. Trinity Episcopal Cathedral in Portland, Oregon was built in 1906 and the original design included 10 operable dormers along the Sanctuary roof. The dormers have since been boarded over, preventing rising heat from escaping. Congregants find the space overheated during the summer months and one must question whether operable dormers would provide adequate ventilation to sufficiently cool the space.

An energy model has been developed using OpenStudio and EnergyPlus to compare the thermal comfort of occupants within the space. A baseline model mimics the existing conditions and provides a comparison for the two different natural ventilation configurations. One natural ventilation configuration re-introduces the operable roof dormers to vent hot rising air. The other natural ventilation configuration re-introduces the operable roof dormers and integrates additional ventilation at the exterior wall of the building to produce stack ventilation.
Trinity Results-wufi-pmapdx

While the project is still in process, initial results indicate that natural ventilation could have a significant impact on the space. The study has focused on the thermal comfort within the Sanctuary and results show that natural ventilation could dramatically lower indoor temperatures during peak summer months.

Trinity Results-wufi-pmapdx

Trinity Results-wufi-pmapdx

The results continue to be fine-tuned, and further refinement of the energy model will include:

• Adjusting schedules/systems to more closely reflect the building’s occupancy.
• More accurately defining the exterior infiltration rates.
• Exploring more relevant solutions for integrating stack ventilation that don’t require the large operable exterior windows. For example integrating ventilation through the basement into the main sanctuary.

While further research remains to be done, initial results are promising and demonstrate the inherent sustainability of the structure. While each building is unique, this Case Study shows how reintegration of natural ventilation may be a viable solution for passive cooling in uncomfortably warm historic buildings. Continue to check back for updates as we refine our study and explore how re-integration of natural ventilation may result in energy savings!

Written by Halla Hoffer, Architect I

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.
John Yeon 2012 004
Case Study 1
John Yeon’s 1948 Portland Visitors Centerwas 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.
WS Scheme 3 Entrance 101209Space 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
120907 Lovejoy Pavillion 002Moore, 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.

120907 Lovejoy Pavillion 009The 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.

PMAPDX-survey-city-of-portlandCase 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.

Written by Peter Meijer AIA,NCARB, Principal
portlandbuilding-model

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.
300px-Court_of_Honor_and_Grand_Basin
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.
Boston Valley new TC
Exterior ornamental terra cotta was marketed as a light weight water proof cladding. And 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.
121022 QAHS S Elev 094
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.

QAHSCWhen 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.


Written by Peter Meijer AIA, NCARB, Principal


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Sources
• 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 endanger of disappearing.

Port of Tillamook 2010 Preproprosal Meeting 061510 006
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.
POTB Blimp Hangars
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.

POTB HanagarCreative, 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.

To learn more about PMA’s experience at the Port of Tillamook Bay, please visit: PMA + PoTB


Written by Peter Meijer AIA, NCARB, Principal

Conservation: A Case Study between Art and Architecture

The Oregon State Capitol
The Oregon State Capitol is a landmark of Modernistic design based on Classical Architecture, and was designed by the New York architectural firm of Trowbridge and Livingston in association with Francis Keally. Completed at the height of the Depression in 1938, the Capitol received funding assistance from the Federal Emergency Administration of Public Works (P.W.A.). Constructed of reinforced concrete, the building is distinguished by angular, unadorned exterior elevations and a massive, ribbed lantern – all sheathed in brilliant white Vermont marble. Artists of national reputation, Ulric Ellerhusen, Leo Friedlander, Barry Faulkner, and Franck Schwarz, collaborated in the winning design and were employed at the recommendation of the architects to produce sculptural relief and paintings of a taut and finely wrought decorative program. Erected in the Modernistic style, the Capitol was sensitively enlarged in 1977 by the Portland firm of Wolff Zimmer Gunsul Frasca in association with Pietro Belluschi.
OR State Capitol Building
On Labor Day 2008, a construction fire damaged the exterior Vermont marble, interior Oregon walnut wood panels and a painting by Barry Faulkner adorning the Governor’s Ceremonial Suite. A team of preservation architects and art conservators collaborated to guide the faithful restoration of this important Oregon icon. All restoration work was based on historic research and field analysis of existing materials, but conservation principles were applied differently to the restoration of interior finishes compared to The State of Oregon artwork by Barry Faulkner.
OR State Capitol Fire Destruction Interior
Fire destroyed all the wood panels on the south wall and caused extensive smoke and heat damage on the east and west walls. The north wall suffered minor smoke damage with little to no impact from heat. Oregon Walnut, a species of wood no longer readily available or milled, was incorporated into 30” x 30” veneer panels separated by 1” wide solid walnut splines. Each panel was book matched resulting in pairs of cathedrals providing strong visual character. It was determined through both field and laboratory testing that the original finish system was a shellac formula readily used during the late 1930s. Conservation strategies had to consider: proper dismantling techniques of the remaining panels; reproduction of original finishes using volatile compounds or the replacement with new finishes; repair options for the various degrees of damage to the wood panels, incorporation of new replacement panels, and anticipate potential similar catastrophic events in the future.
Restored OR State Capitol interior
The remaining panels were measured, documented and classified by the extent of damage. Drawings were produced that recorded each panels’ location relative to the adjacent panel and position on the wall and compass orientation. It was determined that each panel and spline were individually blind nailed to a wood lath support grid which was in turn directly fastened to a back-up clay tile wall. Remaining panel construction from the south wall provided evidence of the construction techniques. As a result, it was determined to the remove the panels in an assembly as large as practical for transportation to a controlled restoration shop environment. At the shop, a more thorough, up-close evaluation of the damage was surveyed. During review of the restoration options, discussion ensued over the incorporation of pre-existing conditions, post fire damage, to include evidence of repair, or should all the panels have a uniform appearance.

After considering the impossibility of achieving uniformity with new panels and cleaned and repaired panels, it was decided to remove all finishes, including the protective shellac, by sanding to bare wood. Following the removal process, each panel was stained to match a patina color visible on a panel protected from damage. The final clear coat was a catalyzed finish formulated to provide long-term protection.
Damaged OR State Capitol Art
To further embellish the Governor’s Suite, a map of the State of Oregon was painted by Barry Faulkner, signed and dated in 1938. The work was framed within the wood paneling over the marble mantel on the ¬East end of the Governor’s Suite. Faulkner painted the work in oil on canvas that was subsequently marouflaged to a section of the wall. This section of the wall was clearly part of the original design of the room and was reserved and prepared especially for the painting. As was customary in New Deal era murals, Faulkner’s work was painted on canvas off site and then adhered to the wall when the construction process was advanced or complete. Also quite typical of New Deal murals was the use of a lead paste adhesive for the marouflage, which was suggested in the later W.P.A project guidelines to the artists. The presence of the lead paste adhesive proved to be decisive in the formulation of a method for the deinstallation of the piece. The tenacity of the adhesion of the canvas back to the plaster via the lead paste is such that separation of the canvas from the plaster was impossible, and so the entire section of wall needed to be removed intact for the conservation treatment. The section of wood framing was carefully removed from the clay tile wall substrate by severing the nails that fastened the wood to the tile, and cutting the vertical studs above and below the work. Special precautions were made to protect the fragile paint surface during transport of the work to the conservation lab.
Damaged OR State Capitol art detail
The fire’s effects caused extreme heat damage to the painting primarily in the upper and right areas of the composition, with numerous areas of blistered paint, and many sections of blistered delamination of the canvas from the substrate plaster. The combustible by-products of the fire combined with embedded soot and smoke created a deposited layer of darkened material that obscured the image. The solubility testing results were consistent with the combustible origin of the fire, and a solution of organic solvents was used to remove the deposited surface material, revealing the original chromatic palette of the work. It also became evident that the painting had been cleaned in a previous treatment. The fragile areas of heat-blistered paint were consolidated and smoothed. The areas of blistered delamination were brought back into plane with localized use of humidity and mild head and then, once smoothed into place, were adhered to the substrate plaster. The large blister in the upper right corner of the painting protruded 1 ½” from the plaster surface. Areas of loss were filled, textured and retouched to match the original surface and color. A protective layer of varnish was applied to the painting.

The exposed finish plaster surrounding the painting was also cleaned with dry sponges, consolidated and filled. Some original pencil drawings by the artist were found on the plaster that had been hidden under the paneled frame.
restored OR State Capitol art detial
The most extreme heat damaged areas were irreversibly altered in both their color and texture, and the full extent of the color shift was not revealed until after the cleaning process. In these darkened areas, Gamblin conservation colors were applied over the varnish layer to retouch the creamy yellow ground color only, leaving the darkened red color of the letters in THE STATE OF OREGON untouched. This manner of retouching allowed the painting to acquire a more finished appearance in line with the decisions made regarding the restoration of the wood paneling, while conserving also the memory of the history of the piece.


Written by Peter Meijer AIA, NCARB, Principal. A special thanks to Nina Olsson, Nina Olsson Art Conservation, LLC, who helped write this post in conjunction with Peter Meijer. Nina Olsson Art Conservation , LLC is a private practice for the conservation of paintings and polychrome sculpture based in Portland, Oregon.