Tag Archives: conservation

Post Modern Building Materials Part Two

Post Modern Architecture: Documentation and Conservation
At the DoCoMoMo US, Modern Matters, conference April 2013 in Sarasota, Florida, DoCoMoMo Oregon presented a debate on the merits of Michael Graves Portland Building and on the larger context of Post Modernism in general. A lively debate at the end of the presentation centered on the merits of DoCoMoMo incorporating Post Modern under the mission of the organization. In general, the support, or lack of support, for an expanded interpretation separated into two distinct viewpoints. The division represented the difference between individuals that look at Post Modernism as a historic event and individuals that still perceive Post Modernism as bad design even if executed within their own practice.
pomo-part-two-document
In a seemingly short period of time, a lot has transpired since 2013 regarding the conservation of Post Modernism. After a presentation on Post Modernism: Are You Prepared to Protect It during the Modern Heritage track at the October 2014 Association for Preservation Technology (APT) Conference in Quebec City, the APT Board unanimously supported the need to get ahead of the technical issues associated with preserving Post Modern architecture.

And in December 2015, the Princeton School of Architecture, educational forum for Michael Graves, hosted the Postmodern Procedures Conference. Described in the conference outline, there was a “particular emphasis on methods of documentation and analysis, technical and narrative drawing” related to Postmodern. Post Modern works, buildings, sites, and neighborhoods, as well as art works, are recognized as important design styles deserving conservation and further understanding of construction techniques. And many iconic structures are being negatively modified (Richard Meier, Bronx Development Center, 1977) or lost entirely (James Wines, Sculpture in the Environment (SITE), Best Product Stores, circa 1976). <1>

Post Modern design was broadly practiced in both the United States and internationally. Large and small firms were attracted to the stylistic incorporation of classical western design vocabulary in stark juxtaposition against the plain, unadorned, square box that many argued architecture had become. Post Modern architects, engineers, and material suppliers were pushing new materials and innovative construction technologies as a way to create Post Modern design elements. Continuous innovation in building skins reintroduced porcelain enamel panels, a product brought by Lustron to the building industry during the housing boom following World War II. New skins made from Glass Fibre Resin (GFR) capable of being molded in classical curves and ornamental shapes favored by Post Modern design were created. Innovations in brick technology including large scale brick panels made from a single wythe of masonry to panels whose outer face was only one half inch of masonry, or thin bricks. Improvements in resins created new wood or simulated wood products and adhesives for mounting faux finishes to structural systems. Perhaps one of the more ubiquitous new materials used in the creation of Post Modern architecture was the faux stucco product Dryvit, an Exterior Finish Insulation System (EIFS). Like porcelain enamel panels, EIFS was introduced as insulated wall assemblies as a means to improve energy performance during the world’s energy crisis of the 1970s.

Outside of dramatic assembly failures, particularly within the EIFS industry, that provide insight into Post Modern material and assemblies, much technological information has been relegated to the historical archives. Many Post Modern buildings incorporate systems or components that are neither produced nor currently assembled in similar manners due to improvements in technology and building envelope science. Therefore, the process and method of building restoration, rehabilitation, and/or focused envelope repair could dramatically impact the exterior character of Post Modern structures.

Focusing on one popular building skin material, Alucobond, much in use during the 1980s provides insight into the need for more research and deeper understanding of Post Modern assemblies and how to conserve and protect these systems.
portland-building-materials-detail
Origins & Development
Alucobond falls into the category of aluminum composite panels (ACP) or sandwich panels. Alcan Composites & Alusuisse invented aluminum composites in 1964 and commercial production of Alucobond commenced in 1969, followed by Dibond in 1989.<2> ACPs are used in a variety of industries ranging from aerospace to construction. Perhaps the most well recognized structure using ACP is the Epcot Center’s Space Ship Earth built in 1982. However, it is the work of Richard Meier and I.M. Pei during the 1980s that brought Alucobond into the forefront as an architectural cladding material. Several different skin materials are available including aluminum, zinc, copper, titanium and stainless steel.

Manufacturing
The major aluminum raw ingredient, bauxite, is mined throughout the world with US sources coming from Georgia, Jamaica, and Haiti. Processing of the bauxite predominantly occurs near the ocean ports, like Corpus Christi, where the raw material is off loaded. Manufacturing starts from either solid blocks of aluminum made into coil sheets or directly from pre-manufactured coil sheets. Assembly occurs along a continuous operating line that bonds the weather (exterior) and interior faces to the core, cuts the panel to length, and produces special shapes as needed.

Aluminum Composite Panels (ACP) are high-performance wall cladding products typically consisting of two sheets of nominal 0.020″ (0.50 mm) aluminum permanently bonded to an extruded thermoplastic core (polyethylene). Assemblies in the mid-1980s would often consist of curtain wall sub-components with sheets of aluminum on the exterior and insulation placed behind the aluminum sheets. (See fig)

ACP can be roll formed to curve configurations for column covers, architectural bullnoses, radius-building corners and other applications requiring radius forming. This process can be accomplished with a “pyramid” roll forming machine, which consists of three motor-driven adjustable rollers. You can successfully roll form ACP using machines with minimum 2 1/2″ (64 mm) diameter rolls. The operator normally makes multiple passes of the panel through the rollers to gradually obtain the desired radius. <3>
pomo-part-two-methods-install
Use & Methods of Installation
Post Modern assemblies generally assumed water would get behind the face aluminum panel and need a weep path to exit the system. Air gaps were incorporated to induce drying and allow for weeping via gravity. Wind loads were accommodated through additional brackets, or stiffeners, set behind the face panel and connected to sub-framing. Much of the technology was based on curtain wall knowledge.

The panel systems could often be complex in the attachment to the structure, but the face panels were very similar to panels of today.

Conservation
Deterioration mechanism are generally associated with the system assembly and rarely are there failures in individual panels beyond cosmetic damages to the face aluminum including fading colors, scratches, and impact damages. More often incorrect fasteners were used that create galvanic reaction between the fastener and aluminum panel or inadequate fasteners were used to accommodate structural loads. The lack of design for thermal movement between panels, over the height and length of the panel façade, or along edge interfaces with sealants are also key areas of assembly failures.

Fortunately manufactures of Alucobond, or other aluminum composite panels, are still manufacturing the panel and components making in-kind replacement a viable conservation option. Inadequate structural systems can be reinforced through disassembly of the ACP for access to the structural support. Laser scanning technology has greatly enhanced the accuracy of recording existing conditions and is critical in reproducing replacement panels. Although labor intensive, most of the systems were attached using stainless steel fasteners. Like modern curtain walls, sealant and gaskets will be removed during disassembly and require reinstallation.

Repainting or repairing surface defects is feasible but the results generally do not achieve the same quality of finish as the factory applied coating process. And as with all repainting projects, surface preparation is critical to the long-term success of the project.

Loss of original Post Modern aluminum composite panel systems can be reduced through an increasing interest and research into the original design intent and assembly techniques. ACP were incorporated into Post modern structures because of the simplicity to create the curved forms and for rapid pace of construction. The systems are an important part of understanding Post Modernism and worthy of Conservation.

Marquette Plaza (historic photograph)

Marquette Plaza (historic photograph)

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.