Tag Archives: PMA Findings

Long Term Impacts of Masonry Waterproofing Sealers

Product X works as a masonry sealer, but what are the long-term ramifications of using Product X on masonry buildings? Masonry sealers come in a wide variety of formulations, but how do the various chemical compositions react to environmental conditions and what affect does the formulation have on the masonry? Most masonry waterproofing sealers specified by architects and conservators, installed by contractors, and requested by property owners are based on Silicone (═Si═ ) chemistry. There are three popular groups of silicone based materials being used as waterproofing materials: 1) silicates, 2) the group of silane, siloxane, siliconate; and 3) silicones. Silicates, similar to Product X, provide waterproofing properties by filling the pore structure of building materials with silicon dioxide (SiO2) precipitation. Common silicates are sand, Portland cement, and other natural occurring minerals. Silanes, siloxanes and siliconates provide waterproofing properties by bonding with the substrate. They are often referred to as penetrating sealers. Silicones do not form chemical bonds with the substrate. Silicones provide waterproofing properties by forming a non-bonded film. Such products are labeled as thin-film sealers.
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SILICATES
Silicates are most commonly used in crystalline type water proofing agents for concrete. Their use is generally focused on concrete substrates. However, it is known that strongly alkaline, aqueous solutions of methyl silicates can be used to impregnate masonry. Such solutions often depend upon caustic soda for their alkalinity. Impregnation of masonry with such solutions is often disadvantageous, however, particularly due to the high alkalinity. For example, the high caustic soda content of the solution will cause a gradual removal of the organosilicon compounds from the interstices of the masonry by chemical combination with the surfaces of the masonry surrounding the interstitial voids. Moreover, the caustic soda solution reacts with carbon dioxide or other acidic components of the air which gives rise to salting out and the formation of efflorescence on the masonry. (1)

SILANE, SILOXANE, SILCONATES
Silane, siloxane, silconates are penetrating type of sealants. Their effectiveness is dependend on the porosity of the substrate and the dosage of repellant applied. Each manufacturer will have unique requirements for the application and dwell time of their sealer. Silanes and siloxanes form a chemical bond with siliceous containing materials. Silanes and siloxanes go through three reactions when applied to a masonry surface: hydroloysis, condensation, and bonding. During the condensation phase, the moisture vapor transmission rate is critical to preventing moisture accumulation behind the sealer layer.

With penetration type sealers, it is critical to the longevity of substrate (masonry) that the moisture vapor transmission of the sealer is actually known. There has been very little third party testing of vapor transmission and each product manufacturer provides varying ways of testing transmission. In addition, the active ingredient content of the sealer formulation and the coverage rate will greatly affect the moisture vapor transmission. In other words, performance in the field will vary greatly from highly controlled laboratory testing.

Siliconates are water soluble and they impart water repellency on porous surfaces. A drawback to using diluted siliconate solution for waterproofing applications is that siliconates react with carbon dioxide and carbonatious matters present in the substrate to form a water repellent, water-insoluble, white colored precipitate. This white layer may become quite visible and require aggressive removal procedures resulting in objectionable appearance or scarification of the surface during removal processes.

SILICONE
The effectiveness of silicone sealer depends on the alkyl group used (which directly influences its resistance to alkaline conditions), the amount of exposure to ultraviolet light and the level of moisture in the masonry when the silicone is applied. (2)

The proliferation of masonry coatings on the market, and the continued pervasive use of the coatings, requires the architect, engineer, contractor, and conservator become more knowledgeable on the wide variety of coating formulations, the continued evolution of those formulations, and understand both the right application of the product and potential detrimental effects of using the wrong product on historic substrates.

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CASE STUDY: WASHINGTON STATE UNIVERSITY, DUNCAN DUNN HALL
In preparation of a major renovation, Peter Meijer Architect, PC was retained in 2010 to conduct a general exterior condition assessment of Duncan Dunn Hall on the campus of Washington State University, Pullman, Washington.

Duncan Dunn was constructed in 1926 as a women’s dormitory for Washington State University, then named Washington State College. It is located in the heart of the WSU campus, facing north towards Linden Avenue. First known as the “New Dorm,” the building cost $150,000.00 to build at that time, and could house 140 students. The architect, Stanley Smith, was the head of the department of architectural engineering and was also the official University Architect.
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The predominant material present on Duncan Dunn is a solid brick unit, brownish red in color, and approximately 8” x 3 7/8” x 2 3/8” in size. At the time of assessment the brick had a very prominent unsightly, white coating over 60% of the masonry facades.

WSU-PMAPDX_masonry_sealers-003 Believing the white haze was a result of UV degradation of a masonry sealer, PMA conducted Reunion Internationale des Laboratoires D’essais et de Recherches sur les Materiaux et les Constructions (RILEM) tube tests of water absorption on the exterior brick on Duncan Dunn Hall. The area of brick chosen for the test was out of direct sunlight to avoid affecting the results and was conducted during dry weather. No movement of the water over a 45 minute period was recorded during the test. Masonry units, even those constructed with high quality clays under controlled firing conditions will absorb some water. The results of the field test on Duncan Dunn, along with the white surface haze, reinforced the assumption of the presence of a masonry coating.

Communication with WSU personnel and their internal research surmised that “the building may have had a sealer put on after the original construction. [WSU cannot verify the application through original records] but do know [that a sealer] was not used on a regular basis after [construction completion.] Back in the 70’s some “miracle sealer” of some sort was introduced on Campus and used at a few locations. Duncan Dunn Hall was among the buildings [receiving masonry sealers.] Today you can see the remnants of this as a white powdery surface that almost looks like efflorescence. [WSU] does not know the name of [the sealer] product.”

To confirm the presence of the sealer, PMA conducted lab testing via polarized light microscopy (PLM) episcopic microscopy, capillary fusion and Fourier-transform infrared spectroscopy (FTIR) per ASTM D1245 and E1252, respectively. FTIR indicated the material to be Poly(2-hydroxypropyl methacrylate), an initially water-miscible acrylic polymer that in these samples is at present very brittle and sloughs rather easily.Testing confirmed the presence of a “water-miscible acrylic polymer”. Due to chemical breakdown under UV, the chalky coating remaining on Duncan Dunn is no longer soluble in water.Because of the insoluble nature of the white haze, low pressure hot-water cleaning methods would not be successful. PMA recommended the Rotec Vortex cleaning system using a mirco-abrasive mixture of dolomite, water, and air. Ultimately this removal processes was successful with no damage to the masonry surface.

(1) Patent application for new formulation of sealers. (2) Types of Masonry Water Repellents, GSA web site. Information derived from ProSoCo Inc. product literature.

Written by Peter Meijer AIA, NCARB / Principal

Analyzing Historic Masonry Wall Performance

Wilmer-Davis Hall is a residential complex on the Washington State University (WSU) Pullman campus. Built in 1937 by Architect Stanly Smith, with John Maloney, the six-story structure is composed of masonry and concrete with a masonry/brick veneer in the classical and Georgian Revival architectural styles. For a recent feasibility study of the complex, PMA provided an exterior assessment and a limited moisture study utilizing Wärme Und Feuchte Instationär (WUFI), an industry standard application in predicting wall performance to determine how additional insulation may impact the existing constructions and wall performance.

The primary concerns of this analysis included increased potential for freeze thaw action and increased mold growth as a result of added insulation. When historic buildings are insulated the insulation is typically added to the interior of the structure to prevent alterations to the exterior appearance. This often causes the outer layers of the wall to be both colder and wetter as the materials are no longer warmed and dried by the interior heating system. The additional water and more extreme temperatures can result in an increase in freeze thaw action, corrosion of metal reinforcement, and/or increased mold growth.

Additionally adding insulation to a wall changes the location of the dew point within that construction (the point at which vapor in the air condenses into water). A dew point within the middle of the wall can also result in increased moisture within the wall cavity. If a wall has difficulties drying due to any of the above causes it is possible that over the course of several years the quantity of water within the wall will consistently increase. Accumulation of water will exacerbate reinforcement corrosion and mold growth and can result in increased freeze thaw action. This study focused on the following metrics to analyze proposed wall performance: quantity of water in the assembly, quantity of water in each material layer, relative humidity in layers susceptible to mold growth, and isopleths.

MODEL SETUP
As in any simulation analysis a number of assumptions were made regarding the existing wall construction and the proposed design conditions. A variety of different conditions were analyzed in order to explore the range of conditions and variables. Below is a description of the inputs as well as an analysis of the results.

Four (4) proposed wall constructions were analyzed to determine how different types, quantities, and configurations of insulation would impact the existing constructions. The configurations were based on outlined solutions for meeting Washington State Energy Code (WSEC) or providing improved thermal comfort. Two of the proposed constructions meet WSEC (Option 1 and Option 2), while two of the solutions (Option A and Option B) fall short of fully meeting WSEC, but would provide improved insulation values. The options simulated included:

Base Case (Existing Conditions) (R-4.8)
3-1/2” Masonry
1” Air Gap
7-1/2” Hollow Clay Tile Back-Up Wall
1-1/2” Plaster

Option 1 (Meets WSEC) (R-15.4, continuous insulation)
3-1/2” Masonry
1” Air Gap
7-1/2” Hollow Clay Tile Back-Up Wall
1-1/2” Plaster
2” Expanded Polystyrene
Vapor Retarder (1perm)
0” Gypsum

Option 2 (Meets WSEC) (R-20.9, insulation is not continuous)
3-1/2” Masonry
1” Air Gap
7-1/2” Hollow Clay Tile Back-Up Wall
1-1/2” Plaster
3” Batt Insulation
0-1/2” Expanded Polystyrene
Vapor Retarder (1perm)
0-5/8” Gypsum

Option A (R 17.4, insulation is not continuous)
3-1/2” Masonry
1” Air Gap
7-1/2” Hollow Clay Tile Back-Up Wall
1-1/2 Plaster
2” Foamed-In-Place Polyurethane
Vapor Retarder (1perm)
0-5/8” Gypsum

Option B (R-18.4, insulation is not continuous)
3-1/2” Masonry
1” Air Gap
7-1/2” Hollow Clay Tile Back-Up Wall
1-1/2” Plaster
3-1/2” Batt Insulation
Vapor Retarder (1perm)
0-5/8” Gypsum

MATERIALSIt should be noted that no material testing was performed during this phase of the project – instead default material properties were chosen from the WUFI database. Materials used include:

Masonry: The material ‘Brick (Old)’ was used to simulate the existing masonry. The material is a generic historic brick material compiled from a variety of different bricks and included in the WUFI database.

Airspaces: All airspaces were modeled without additional moisture capacity which according to WUFI, models more realistic moisture storage in air cavities.

Hollow Clay Tile: The historic drawings indicate that behind the masonry is hollow clay tile. WUFI does not have a default material for hollow clay tile. Instead a masonry material ‘Red Matt Clay Brick’ was used to represent the solid portions of the clay tile. Air spaces were used to simulate the hollow portions of the tile.

Historic Plaster: The WUFI database does not have a default historic plaster material. The ‘Regular Lime Stucco’ material was used to simulate the existing plaster.

Batt Insulation: ‘Low Density Glass Fiber Batt Insulation’ was used in simulations.

Rigid Insulation/Expanded Polystrene: ‘Expanded Polystyrene’ was used in simulations.

Fomed-In-Place: ‘Sprayed Polyurethane Closed-Cell’ was used in simulations

Gypsum: ‘Interior Gypsum Board’ was used in simulations.

Weather/Interior Conditions In each simulation the model was set to mimic extreme situations to verify that the existing walls will perform in all conditions. The Spokane, Washington weather file indicates that the south elevation should have the most wind driven rain and moisture impacting the wall. Given this information the analysis used south exposure and the Spokane weather file to simulate exterior conditions. For the interior climate conditions the following profiles were used:

Interior temperatures ranging from 69 °F to 72 °F

Relative humidity ranging from 50% – 60%

The above values represent a relatively high moisture load which is consistent with the existing use as a residential facility.

Water Intrusion Additionally as per ASHRAE 160 a small leak (1% of driving rain) was introduced into the exterior assembly to simulation a scenario where water was penetrating the exterior surface. This could occur at bondline failures in the mortar or penetrations through the wall assembly. The leak was placed past the masonry veneer on the face of the hollow clay tile backup wall.

Initial Conditions Lastly the initial conditions of the materials were determined using ASHRAE 160. For existing wall materials EMC80 was used as the initial moisture content. (EMC80 is a value expressing an equilibrium of water and material masses at 80% humidity). For new components the expectation was that the materials would be installed from the interior and would remain dry during the construction process – thus EMC80 was used for new components as well.

WUFI RESULTS
Four metrics were used to interpret and analyze the following WUFI results: Total Water Content/Water Content in Material Layers, Temperature, Relative Humidity, and Isopleths.

Total-Water-Contents-WSU-Wilmer-Davis-WUFI-Report-6 Total Water Content WUFI can predict the total accumulation of water over the time frame of the simulation, in this case five years. Over the course of each year a wall assembly will be wetted by the rain, and dry over the summer months. Differences in humidity and temperature between spaces may cause water condensation within the walls. If conditions do not allow condensation or other water to dry, materials may accumulate water over a period of time.

The chart above shows how each of the different simulations performed. Note that total water content is measured per ft2 of wall. Walls that are thinner (existing construction) will inherently have less capacity to hold water. In general all of the walls performed in a similar manner – an indication that the retrofit strategies should perform in a comparable manner when compared to the existing walls. As can be seen in the chart, all of the simulations, including the base case showed some accumulation of water over the five year simulation. These results, however, do not conclusively show that the proposed walls will accumulate water. The results indicate that even the base case is accumulating water over time. During PMA’s site visit, however, the existing exterior walls appeared to be performing well – which would not be the case if they were consistently accumulating water. Additional analysis showed that the gradual accumulation of Total Water Content appears to be a result of initial instability within the wall construction that equalizes over time. A 20 year simulation showed accumulation over the first five years, after which the water content stabilizes.

Water Content in Material Layers Each of the individual layers of material in a wall assembly have the capacity to hold and retain water. A high water content in any individual layer can indicate the potential for mold growth, the possibility for damage associated with freeze thaw, and a reduction in R-Value based on moisture content. Mold growth is possible when the moisture content is above 20% and if the material has the capacity to feed mold growth. The charts below show how each simulation performed for each layer within the wall.

Water-Content-Materials-WSU-Wilmer-Davis-WUFI-Report In general most layers remained well below the 20% threshold for mold growth. The insulation layers, however, are an exception. Options 2 and B both had batt and/or foam insulation which yearly exceeded 20% water. This quantity of water is somewhat concerning for the batt insulation as it may reduce the material’s R-Value and/or contribute to mold growth depending on the composition of the material. Solutions that used foam insulation performed better than those with batt insulation.

Temperature One common result of insulating a historic building from the interior is increased freeze thaw action. Insulation prevents the interior conditioned space from heating and drying the exterior masonry. As a result the masonry is typically saturated with more water and exposed to colder temperatures. The analysis looked at the temperature within the middle of the masonry to determine how added insulation would impact the material. A chart comparing the base case to the four options for insulation is located below. As can be seen the brick temperature remains consistent with the base case in all retrofit options. This is an indication that the masonry may not by exposed to additional weathering as a result of added interior insulation. It should be noted that not all masonry reacts to water saturation and freezing conditions in the same manner. To further analyze the masonry’s susceptibility to freeze-thaw action lab analysis is recommended to determine material performance. If results indicate that the masonry is susceptible to freeze-thaw it will be critical to ensure new constructions do not lead to a significantly colder/wetter exterior wall.

Relative Humidity The relative humidity of the air within the wall construction also has an impact on material longevity and mold potential. A high relative humidity in plaster or batt insulation layers may indicate mold growth, while a high relative humidity in layers with reinforcement may indicate the potential for corrosion. A constant and high relative humidity (above 80%) indicates the potential for mold growth. The charts to the right focus on several susceptible layers, the existing plaster, batt insulation, and gypsum board. In general the majority of the layers susceptible to mold remained below 80% relative humidity, or consistently dropped below 80% relative humidity allowing the material to periodically dry. An exception was the existing plaster layer. The addition of interior insulation caused the relative humidity within the layer to increase approximately 15%, from 65% (base case) to just over 80% (all options for added insulation). This spike in relative humidity is concerning and could indicate the potential for mold growth within the layer.
Materials-Temperature-Relative-Humidity-WSU-Wilmer-Davis-WUFI-Report
Isopleths WUFI can also predict mold growth by plotting isopleths on the interior surface. The isopleths are plots of the temperature and the relative humidity for every time period calculation. When the temperature and relative humidity both exceed the limiting lines calculated by WUFI there is the potential for mold growth. The simulations indicate that there is very little potential for mold growth. All of the simulations begin above the limiting lines, but over time equalize and remain well below the threshold calculated by WUFI.
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CONCLUSIONS
The results described above indicate that there could be some challenges to designing an appropriate insulation system for Wilmer Davis Hall. Three of the primary concerns noted in the above analysis are: increasing total water content quantities; high quantities of water in the batt insulation layers; and consistently high relative humidity’s in the existing plaster layer.

In general Option 1 and Option A performed better than Option 2 and Option B – primarily because they relied on only foam/rigid insulation. This resulted in no risk of mold growth within the insulation layers and no reduction of the R-Value. Concerns were still identified with both Options in terms of total water content and relative humidity in the plaster layer.

Prior to detailing a new wall for construction additional analysis is recommended. Minor changes in material properties can have significant impacts on wall performance. The above analysis has indicated that there is a potential for mold growth, but has not confirmed its likelihood. Most of the metrics indicated no risk of mold growth – however because some of the metrics showed a potential for mold, additional analysis is recommended. Testing of the existing materials and specific data on proposed products should be used to refine this analysis and determine extent of mold growth risk.

Written by Halla Hoffer,AIA, Assoc. DBIA / Associate, Architect

Overview of Architectural Styles in Oregon: 1840s to 1970s

The City of Gresham applied for and was granted a CLG grant from the State Historic Preservation Office to increase community interest in historic preservation. The City felt that a presentation focused on architectural styles would likely to generate interest among the community. They contacted PMA to provide a power-point presentation geared towards citizens with no planning or architecture background, but also useful for City staff and historians. PMA
presented an overview of Oregon Architectural Styles. We used local Gresham area examples with state-wide examples in the presentation to highlight the residential and commercial styles most likely to be seen in the Gresham area.
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USE, TYPE, STYLE
It is difficult to understand style without an appreciation of the ways style can be overlaid on various types and uses of buildings. The USE of a building is its primary function. For instance, a church (use) might have a hall with steeple (types or forms) and be Neoclassical (style). The use or purpose of a building is strongly linked to its form, but even within a category of use such as residential, one might find various types such as “apartment block,” “bungalow,” or “four-square.”

TYPE just means the basic form, so it is useful for historians to categorize these forms into expected sizes or arrangements of volumes. An apartment block is generally a simple rectangular building with several apartment units and a shared entry. A bungalow is simply a small house, one or 1.5 stories, horizontal in expression. Bungalows are often Craftsman in style, but a handful of other styles are sometimes used with a bungalow type. A four-square is a larger house, typically 2 or 2.5 stories, consisting of a somewhat square footprint with 4 rooms on each floor, and a broad front porch with columns or posts.

The building’s STYLE is determined by the architectural and ornamental details and exterior features applied to the basic structure. Styles change with the times. In fashion and out of fashion, some endure longer. The timeline included is generally reflective of Oregon architectural fashions. However, style also can be affected by technology- for example, the development of steel frame buildings allowed for a new style to emerge: Modernism. Older bearing-wall masonry construction only allowed for small windows set between structural wall areas. A proliferation of new building types, such as the geodesic dome, occurred in the Modern era.

We categorize buildings by type, use, and style when doing a survey of resources in a particular area. The data can be compared quickly and easily to data from other surveys, so we can see the patterns and history of development emerging in any particular area.

STYLISTIC TIMELINE OF ARCHITECTURAL STYLES IN OREGON
From Vernacular Forms and Styles, to Renaissance Revivals, Northwest Regional Style and Post Modern, Oregon has a robust and diverse vocabulary of architecture. The stylistic timeline below is meant as a broad overview, highlighting key attributes per style listed, to help you identify your local Gresham area, greater Metro area, and and PNW regional architectural resources.

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The Form and Function of Lighting Design

When we experience an interior architectural space, lighting plays a large role in setting the mood and functionality of a space. No matter an existing, modern or historic building, light of a space is a critical aspect of great interior design. Lighting elements can be designed to enhance the space and architectural details, set the mood, and compliment furniture, color schemes, and art work. For spaces without an abundance of natural light, lighting design becomes even more critical design consideration. For a recent project, PMA designed lighting schemes for two historic four-story tall interior atriums.

The existing atriums utilize natural light from skylights above; however the original design provided no artificial overhead lighting in the space. During the winter months or at dusk and night, the light quality of space relies on the little ambient light from the skylights or artificial light from the surrounding rooms and halls. The light during these times is inadequate for the necessary function of the space. PMA was tasked with providing a lighting solution that would sensitively address the historic nature of the atriums and provide adequate visibility in the space.
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Defining the Project Challenges
The concepts for our lighting schemes were based on the intended function of each identical space. The focus of the design and specified need of the client was to provide lighting for evening social gatherings, networking, and overall entertaining. Lighting needed to be adequate enough for speakers presenting to a crowd and for listeners to be able to read any related literature. Therefore, it was crucial to design lighting schemes that could provide ample lighting for evening events without compromising the historic integrity and ambiance of each space. To provide a solution for our clients’ challenge, we considered the following when approaching our design for the lighting schemes:

How to provide power to the source of lighting without compromising the historic elements.

Designing for large volumes of vertical space: hanging lighting within the atrium versus lighting from the top; how the light travels in the space, how it casts down shadows, the reflections off the floor and other surfaces.

One atrium exhibits permanent hanging sculptures and art; the lighting design required minimal approach to integrated and highlight the sculpture without distracting from it.

Designing for and highlighting the atriums’ architectural details, like the cornices, in addition how to hide or incorporating other non-historic architectural details like the structural support columns.

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Methodology for Design Solutions
The prominent design goal was to increase overall light levels through a refined, modern scheme that would provide juxtaposition to the historic architectural elements and hanging sculpture. As in any historic project, it is important to avoid solutions that are faux historic, competing with, compromising, or confusing the original historic character. The few pragmatic design parameters defined by the client allowed for design freedom to provide several unique, distinct solutions. While creating our designs, PMA experimented with the type of fixtures (down lights, sconce, defused) and placement of these fixtures within the large volume of the atriums. PMA explored these options in a Revit model of the atrium spaces, which enabled evaluation of the design solutions through lifelike renderings that portrayed the quality and levels of light. Illuminance studies of lux levels provided a way to evaluate each design and provide refinement to meet necessary levels defined by the function of the space. Some lighting design options included:

Design lighting to highlight and contrast architectural features from surroundings, for example placing fixtures in the cove of architecture cornices located above openings within the atrium.

One atrium has a glass block floor element which could be illuminated from below to provide a dramatic light feature.

Accenting the verticality of the space with defused ribbon lighting set within the non-historic structural C-channels. This would transform these elements into elegant vertical lines leading the eye to the above skylights.

Pendant lights interspersed between sculptures would provide orbs of light to highlight elements of the sculpture. These fixtures would provide defused-light with optional downlights within the same fixture.

Suspended down lights at top of atrium with lights accenting sculptures from above and side.

Wall sconces to accents light and wash the atrium walls and columns; this would provide an overall glow to the space.

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Scheme 1 unified serval lighting design ideas to provide different light level options in the space. Wall sconce lights provide general illumination of the space. Large circular hanging fixtures consist of defused tube lights and large circular defused downlights. Each group of fixture types can be controlled independently and dimmed to provide the ambience desired.

Scheme 2 specifically works with the sculptures in the second atrium space. Vertical ribbon lights provide ambience illuminance of the space while concealing non-historic structural elements. Pendant lights hang interspersed within the sculptural elements. These have a defused light with an option for downlights. Each grouping of fixtures can be illuminated together or separately depending on the quality of light needed.

Scheme 3 was chosen by the client and until announced must remain confidential. Stay tuned for the reveal.

Written by Hali Knight.

Post Modern Building Materials Part One

Advances in science and material properties have always played a role in the development of building products. Postmodernism fueled the advent of several new building materials including Glass Reinforced Polyester (James Stirling, Olivetti Training Center, c.1972), Insulated Exterior Metal Panel Systems (Richard Meier, Bronx Development Center, c.1979), Dupont’s Fabric Tensile Structures (University of Florida Gainesville, O’Connell Center, c.1980), polycarbonate sheets (Kalwall, et.al.), pre-fabricated brick panel systems, and many other new construction technologies.

Richard Meier, Bronx Development Center, 1977

Post Modern Building Materials and Life-Cycle
Like any new technology or building material, the life span of postmodern materials is now known but there is a lack of case studies and journalistic papers describing the failure mechanisms, and more importantly, how to repair, retain, or preserve the exterior materials. On one level there is an inherent impermanence of the original materials based on a default decision making process that limited a building’s longevity to a twenty-five (25) year life-cycle. On another level, the façade of the Postmodern building incorporates building systems or individual components that are neither produced nor assembled currently in similar manners due to improvements in technology and building envelope science. In either case, the process and method of building envelope repair could dramatically or minimally impact the exterior character of Postmodern structures.

Aldo Rossi, Theatro Delmondo, Venice 1982

There are some Postmodern structures, despite the polarizing opinions regarding the aesthetic values, that are iconographic examples of the high-end of Postmodern style. Included with those structures named above, are the Portland Building (Michael Graves, c. 1984), Piazza d’Italia (Charles Moore, 1982), and Theatro Delmondo, (Aldo Rossi, Venice 1982) to name a few. Rossi’s Theatro Delmondo poses an even more challenging theoretical debate as to whether or not to preserve or repair the structure since the theater was built as a floating temporary stage set.

Rehabilitation and Postmodern materials
The rehabilitation of Postmodern materials is compounded by the lack of physical or chemical stability in the original product (e.g. color fading or material breakdown by UV light); changing urban context and surrounding development; inadequate original construction means and methods, and lack of precedence – Postmodern buildings are just now reaching the end of their design life-cycle. Proposals to improve envelope performance are challenged in finding products that will improve performance and retain the aesthetics of a Postmodern building. Given these challenges, is the proper repair, rehabilitation, or conservation of Postmodern structures to retain the appearance of insubstantial material installed incorrectly? Or should any new work, often entailing proposals for replacing the building facades, to discount the design appearance and fix the problems regardless of the impact.

ZGF, Koin Center, 1982

Moving forward, there are precedents set by the early and current challenges associated with mid-century modern structures that can be followed. For example, circa 1960 glass curtain wall upgrades have created methods to retain the exterior appearance while upgrading the thermal efficiency of the system or conversely, left the existing original curtain wall in place and upgrade the mechanical system and distribution system as both more cost effective and more energy efficient over the life of the building. The solutions towards postmodern materials will similarly be led by research, initiative, and innovation. Engaging the manufactures in the dialogue is essential, particularly when replacing a failed product is critical to retaining the building design character.

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James Stirling, Olivetti Training Center, 1972

Unique Challenges
There are unique challenges with Postmodern buildings, but as is the case with all new materials and systems, developing a strategy of research, methodology, and documentation will result in extending the life-cycle of these provocative structures.

Portland Building

Written by Peter Meijer, AIA, NCARB / Principal

PMAPDX 2015 Year in Review

HAPPY HOLIDAYS!!

PMAPDX-Holiday-2015

Wishing you a holiday season filled with cheer and delight from Peter Meijer Architect.

As we look back over the past year and reflect on our completed, on-going, and upcoming projects, we’d like to take the opportunity to say we have truly enjoyed collaborating and communicating with you.

2015 PROJECT HIGHLIGHTS

PMA HAPPENINGS
Peter Meijer AIA, NCARB, was a Presenter at the RCI, Inc. 2015 Symposium on Building Envelope Technology. He presented on, When Field Performance of Masonry Does Not Correlate with Lab Test Results. PPS Grant High School was the case study presented.

Kristen Minor, Preservation Planner, is the newest member of the City of Portland Historic Landmarks Commission.

When Field Performance of Masonry Does Not Correlate with Lab Results

First presented at RCI 2015 Symposium on Building Envelope Technology, Nashville, TN

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Background
When it was completed, Grant High School was typical of the high schools constructed by Portland Public Schools in the pre-World War II era. In addition to being an extensible school, including educational buildings constructed between 1923 and 1970, the school was also reflective of fire-proof construction through its use of a reinforced concrete structure with brick in-fill. (Portland Public Schools, Historic Building Assessment, Entrix, October 2009)

Over the last fifteen years, Portland Public Schools (PPS) noted an accelerated degree of masonry face spalling on the original 1923 main building and 1923 Old Gym particularly when adjacent to concentrated sources of surface water. Other areas of spalling were not as obvious including protected wall surfaces. The masonry spalling was not occurring on later additions including the north wing (circa 1925), south wing (circa 1927), and auditorium building (circa 1927). Upon closer visual examination, it was observed that individual units were failing in isolated protected areas of the wall surface. Failures in such areas could not be accounted for under direct correlation of heavy water intrusion and typical failure mechanisms.

The failure of the brick was potentially due to a number of separate or cumulative conditions including 1) excessive water uptake by the brick; 2) sub-fluorescence expansion of salts in the masonry, 3) freeze thaw; 4) low quality of the original 1923 brick; and 5) the application of surface sealers preventing water migrating to the exterior surface.

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Field Investigation
In order to determine if the damage to the masonry was deeper than the surface, several wall-lets, an invasive exterior wall opening, were performed confirming the assembly of a multi-wythe masonry wall constructed in a typical fully bedded bond course with interlocking headers and no cavities between the first three brick courses. Hooked shaped, 3/32” gage, steel wire masonry ties in alternating courses and approximately twelve inches (12”) on center ties were found to be in good condition with no deterioration. The absence of corrosion on the in place brick wire ties indicated that little moisture was present inside the multi-wythe wall.

As a result of the hypothesis and field observations, it was prudent to conduct a series of lab tests to the brick, mortar, and patch materials to assist in the determination of 1) the quality of the brick; 2) the physical composition of the brick; 3) the quantity of naturally occurring compounds in the masonry and mortar, particularly salts in the masonry; and 4) the quality of the mortar. The findings would help narrow the potential cause of the spalling and lead to a more focused repair and maintenance process. Bricks were removed for testing of Initial Rate of Absorption (IRA – a test for susceptibility to water saturation) freeze thaw testing, and petrographic analysis, a way to determine the inherent properties of the clay and manufacturing process. Both pointing and bedding mortar samples, as well as, the previous patching material were removed and also tested. To rule out damage caused by maintenance procedures, faces of the brick material were sent to determine if sealants were used on the brick and, if present, determine the sealant chemical makeup. The presence of a surface coating may lead to retention of water within the brick and thus prevent natural capillary flow, natural drying, and water evaporation.

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Testing & Results
Samples sent to the lab for coating assessment were analyzed via episcopic light microscopy, and Fourier- Transform Infrared Spectroscopy (FTIR) per ASTM D1245 and ASTM E1252. The results found no hydrocarbon or organic formulations used on the surface of the brick refuting the hypothesis of a surface sealer.

Following modified ASTM standards, a 24-hr immersion and 5-hr boil absorption test on the brick were performed. The brick have a very low percent of total absorption at 9.5% for the 5-hr boil and 7.5% for the 24-hr test. The maximum saturation coefficient is 0.79 which is 0.01 over the maximum requirements for Severe Weathering bricks recommended for Portland climate (ASTM C216-07a Table 1). The Initial Rate of Absorption (IRA) is 5.7g/min/30in2 which equates to a very low suction brick or brick with low initial rates of absorption. The freeze thaw durability tests resulted in passing performance. All of these tests refuted the hypothesis that freezing temperatures were the cause of masonry spalling.

A brick material analysis was performed in general conformance with ASTM C856, ASTM C1324 (masonry mortar) and included petrographic analysis, chemical analyses, x-ray diffraction and thermogravimetric analysis. Samples were analyzed under a polarized light microscope for information such as materials ratio and presence or absence of different deterioration mechanisms. These tests were used to assess the overall quality of material, presence of inherent salts, excessive retempering, cracking, ettringite formation, and potential alkali‐silica reactivity.

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The Petrographic Characterization resulted in the most unusual findings and the most relevant results related to the observed failures. The polarized light microscope indicated carbonate based salt crystals seeping into the masonry from the mortar. No sulfate based salts, typically associated with the clays used for making brick, were present. Furthermore the inherent properties of the brick showed very small rounded voids and interconnected planer voids. Planner voids result from poor compaction during the raw clay extrusion process prior to firing.

Performance of brick in the field is a result of both material properties and resistance to micro-climates within the brick’s capillary void structure which cannot be repeated in the lab. Studies have shown a connection between small voids in the material property and susceptibility to longer water retention near the surface. With natural absorption properties, the brick is taking in a small quantity of water in very small pores. 24-hour immersion results are very low (7.5%). Publication of more in-depth studies correlates maximum saturation values for brick with low 24-hour immersion values. The effect of low immersion values and small quantities of absorbed water may increase the susceptibility in brick with small pore structure to freeze thaw failure.

The presence of salt migration out of the mortar and into the brick, plus small pore structure and low immersion values, combining with a cleavage plane resulting from manufacturing are contributing to the Grant High School brick spalls. Brick with smaller pores are less capable of absorbing the expansive forces of freezing water and drying salts. Interlaced pores creating linear plains parallel with the face of the brick create stress failure points resulting in surface spalling. Since the characteristics of the brick resulted from the firing and manufacturing process, the brick will remain susceptible to the failure mechanisms.

Conclusion
Field observations of masonry failures generally correspond with known failure mechanisms. However, it is not unusual that further analysis is necessary to confirm in-field performance and that typical laboratory test results are in conflict with in-situ performance.

The best corrective action is to minimize the amount of surface water and proper mortar joints and mortar composition. Additional spalls are likely to occur in the future due to the accumulation of expansive forces over a long period of time. Replacement of the spalled bricks is recommended over further patching. Leaving spalled brick in place will continue to worsen the condition over time and affect adjacent brick.

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Written by Peter Meijer, AIA, NCARB, Principal

Navigating the Historic Tax Credit Application

Historic Tax Credits were founded in partnership with the National Park Service (NPS) and the Internal Revenue Service (IRS) in 1986. As one of a number of incentives to help owners preserve historic properties, Historic Tax Credits have since become the premier financial incentive towards the rehabilitation of income-producing historic properties. Historic Tax Credits can be used for older, non-historic properties as well, so long as they are income-producing, at a lower credit amount. An owner can receive a 20% rehabilitation tax credit for the amount spent on the qualifying rehabilitation of a National Register-listed property, or 10% tax credit for the amount spent on the qualifying rehabilitation of an older property with no historic status.

There is a minimum threshold of rehabilitation investment that must be met in order to qualify. Rehabilitation project costs must be equal to the Real Market Value (as assessed by the local tax authority) minus the value of the land or $5000, whichever is greater. Rehabilitation Tax Credits for tax-exempt historic properties are possible provided that the investment partner using the tax credits is a for profit, tax paying entity. Typically, separate Limited Liability Corporations are established through which rehabilitation funding flows to the project.
Pacific-Tower-Tax-Credits 20% Rehabilitation Tax Credit
The most common use of historic tax credits is the 20% Rehabilitation Tax Credit. To qualify for the 20% historic tax credit a property must be listed on the National Register of Historic Places either individually or as a contributing resource within a historic district. Properties must be a building as defined by Treasury Regulation 1.48-1(e), income producing, and undergo a certified rehabilitation process, which is evaluated by the NPS and the State Historic Preservation Office (SHPO). This process includes the completion of a three part application: Part 1-Evauation of Significance (not typically necessary if the building is already on the National Register); Part 2-Description of Rehabilitation; and Part 3-Request for Certification of Completed Work. Once completed and approved by the NPS the 20% tax credit can be claimed for the tax year in which the property was certified by the NPS. Tax credits can be taken in phases as well, as long as each phase meets certain conditions.

10% Rehabilitation Tax Credit
To qualify for the 10% rehabilitation tax credit a property must have been built before 1936. Properties eligible for the 10% tax credit must be buildings, income producing, non-residential, and remain on the original site. Historic properties that have been relocated do not qualify. Other conditions include the retention of at least 50% of the external walls, at least 75% of internal and external walls, and at least 75% of the internal framework. Unlike the application process for the 20% Historic Tax Credit, there is no formal review process or certification. However, the tax credits are redeemed the same way. Buildings listed individually or contributing resources within a Historic District on the National Register of Historic Places are not eligible for the 10% tax credit.

Current Trends
The staff at PMA have years of experience navigating the Historic Tax Credit application, placing properties on the National Register of Historic Places, and working with the State Historic Preservation Office and the National Park Service to assure the rehabilitation project qualifies and receives historic tax credits.
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From initial application of Part I through final certification of Part III, 180 days or more can elapse. Current development practices and financial investment processes place pressure on the development schedule to initiate rehabilitation prior to final approval by the National Park Service. Early construction places the tax credit under risk and final approval can be withheld pending review of all rehabilitation impacts. Market demand for open space with exposed mechanical, electrical, and plumbing systems is creating a trend in rehabilitation of historic properties to expose these functional systems.

PMA’s experience in working with the market demand and reaction to the trend by SHPO and NPS, can provide owners with advice on where reviewers will be more stringent. PMA has worked with NPS when a Condition of Approval was placed on the submitted Part 2 Description of Rehabilitation requesting alteration of completed ceiling conditions throughout the building in occupied space. Although the owner did know that construction prior to approval was a risk, they also needed to have some spaces complete in order to retain certain tenants and meet the financial loan terms. PMA sought a compromise with NPS retaining completed ceilings, but altering the design intent and finish in those spaces not yet complete in order to meet the new Condition of Approval.
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Similarly, PMA has noted in the Part II application process an acceptance of exposed fire sprinkler lines and exposed conduits but resistance to exposed ductwork and exposed cable trays. Whereas it could be argued that exposed mechanical and wiring systems are akin to exposed electrical systems in that the exposed work does not have a long-term impact on the historic walls, floors, and ceilings, the combined affect changes the subjective visual impact from NPS perspective.

Each of the above trends requires diligent documentation and on-going discussion during the construction process, which, in itself, can be very fluid and entail rapid changes. The tax credit consultant must be skilled in communication and work with both the development team and tax credit reviewers.

PMA Technical Assistance
PMA is proud to undertake historic tax credit commissions as these projects have been a great way for our office to combine our specializations in architecture and preservation. Over the last five years, PMA has completed numerous Historic Tax Credit applications throughout Oregon and Washington. Overall, Historic Tax Credits have proven to be vital to the financial proforma and successful investment strategy to preserve and rehabilitate historic properties.
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Written by Peter Meijer AIA, NCARB, Principal / Kristen Minor, Preservation Planner / Brandon Grilc, Preservation Specialist

Assessing Union Station to be Part of Our Future

Portland’s Union Station is the only major railroad station built in Oregon, and one of the oldest major extant passenger terminals on the West Coast. From its inception, Union Station has functioned as a major transportation link to Portland and the west coast, with a continued vital role to play in future rail and multimodal transportation planning.
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A Sense of Place
Critical to adapting Union Station, and other historic structures, for current and future use is to thoroughly understand key elements and components that convey the sense of place and rich history of the structure. A deeper understanding enables informed decisions to be made about the potential of key characteristics to remain for future generations. Union Station was constructed between 1892 and 1894 and was designed by Van Brunt & Howe architects in the Queen Anne style with Romanesque detail. From 1927 thru 1930, the Main Concourse was modernized by Portland’s internationally known architect, Pietro Belluschi, to reflect the streamline era of rail technology. Like the original 1892 elements, the Belluschi modernization’s are equally important stories to tell.

Creating a graphic document annotating “changes over time” is an essential tool for evaluating how Union Station has adapted to improvements in rail technology, fluctuations in passenger volume, cultural shifts regarding train travel, as well as modifications to specific architectural elements that impact the historic integrity and interpretation of original design intent.
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Methodology for Assessment
Our method of developing the graphic drawing is to compare historic floor plans and historic photographs to current plans and images through a process of layering plans from different eras over one another and drawing the altered, or missing, elements (e.g. walls, furniture, spaces, etc.) in different colors. This methodology provides an easily interpreted floor plan. The use of color enhances the image and creates a visual record of both changes and original historic fabric. In reading the graphic drawing, it becomes readily discernible that changes include: wood floors replaced with concrete and new floors added; openings in the main concourse were moved and enlarged; the women’s waiting room and toilet were removed to widen the south hall, the stairs were renovated, and a new baggage counter was constructed. The covered concourse was glassed in and a section was made into the First Class Lounge, which remains today. And in the 1940s, a nursery, or crying, room was added.
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What is fascinating about the history of a building like Union Station, is that the rail lines and street patterns are also integrated with the function and use of the structure and have changed over time as well. The construction of Union Station came soon after Portland was fully connected by rail in 1883 to California, Montana, and rail lines running to the East Coast across the U.S. The Spokane-Portland-Seattle rail connection was finished in 1908. In 1922, Union Station became accessible to all major passenger railroads operating through Portland.

When originally constructed, six passenger car rail lines approached the rear of Union Station. The waiting platform consisted of planks on dirt with no canopy. The block across from Union Station consisted of a small restaurant, bar, other stores, and stables. A five foot iron fence bordered a large lawn and sidewalk to the south and west of the station. The High Shed, a large two-story metal shed was the first canopy built to cover the passenger platforms and extended perpendicular to the station. Under this High Shed, two smaller scale platform canopies were erected paralleling the tracks. A mail canopy was built at the north end of the building in 1915.

By 1920, the block across from Union Station’s main entrance had been converted to parking to relieve congestion. As automobile use increased throughout the city, parking configurations were constantly changing over the years. By 1923, an elevated walkway was built to connect the Broadway Bridge to the main entrance.
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With the introduction of larger diesel locomotives and potential for high speed rail along the northwest corridor, the track, platforms, and canopies have had to be modified. Safety and accessibility have also driven the need for changes and modernization. Documenting these alterations with graphics, provides a foundation from which to advocate for further refinement while recognizing historic precedent and protection of historic elements.

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Written by Peter Meijer, AIA,NCARB, Principal

PMA is part of the DOWA-IBI Group team for this exciting PDC Union Station Renovation Project.

Ballpark Preservation and Its Most Recent Event

civic-stadium-eugene-prefire Since its creation in 1862, the ballpark has continued to have an influential impact on those who experience it. This impact is not only measured by heritage tourism to these sites, like Fenway Park or Wrigley Field, but also by how they are preserved. In some cases, such as Fenway Park, which is listed on the National Register of Historic Places, ballparks are preserved in a very traditional sense of the word. However, most ballparks never have the opportunity to reach the benchmarks needed to be preserved according to these preservation standards and are therefore preserved through a variety of alternative preservation methods. These methods, which span the spectrum from preserving a ballpark through the presentation of their original objects in a museum to the preservation of existing relics in their original location, such as Tiger Stadium’s center field flag pole, have given a large segment of our society an opportunity to continue their emotional discourse with this architectural form. Yet, the results of these preservation methods are commonly only the conclusion to a greater act of ceremony and community involvement that preludes them.

civic-stadium-eugene-prefire-002 Part of this ceremony and community involvement is the simple act of participating in the ritual that is the game itself. Most often this is conducted through observation, as society, architecture, and sport become one for nine innings. However, other documented examples of ceremony and community involvement that express the level of compassion our society has for ballparks include ritualistic acts, such as the digging up and transferring of home plate. In some cases, this ritual has included the transferring of home plate via helicopter, limousines, or police escort. Ceremonies like this have also included, for better or worse, the salvaging of dirt, sod, and other relics from a ballpark to be, either cherished as a memento or repurposed in new stadiums. Nevertheless, these examples of ceremony only scratch the surface of the depth that is our society’s infatuation with sport and its architecture, more specifically the ballpark.

civic-stadium-eugene-postfire Ceremonial Acts & Community Involvement Efforts
Some of the most recent ceremonial acts and community involvement efforts that help to further this commitment to ballparks are the acts executed by the Friends of Civic Stadium in Eugene, Oregon. Founded in 2009, the Friends of Civic Stadium have dedicated countless hours towards preserving one of our country’s last wooden ballparks. These efforts include years of community activism, documentation, fundraising, and grounds keeping. Collectively, these efforts resulted in the prolonged life of the 77-year-old ballpark, as they fought off national corporate efforts to purchase and demolish the stadium. But, in an ironic twist of fate, all of the hard work, collaboration, and time spent on preserving a single ballpark came to an abrupt halt on June 29, 2015 when Civic Stadium caught fire and burned down in a matter of hours. Left with only charred remains and a distraught community, the Friends of Civic Stadium moved on in the only way they knew how, through ceremony.

civic-stadium-eugene-postfire-003 Led by the Friends of Civic Stadium president, Dennis Hebert, the organization held a wake in honor of their lost historic building. The wake, intimate in size, resembled a jazz funeral with a procession to the remains of the ballpark led by the One More Time Marching Band. Once at the site of the ballpark, there were multiple ritualistic acts that mimicked traditional funeral ceremonies. These acts included a moment of silence, a passionate speech by Dennis Hebert, and the always haunting rendition of Amazing Grace on bagpipes. After the ceremony, the Friends of Civic Stadium and the friends of Friends of Civic Stadium proceeded back to Tsunami Books where they continued to express their condolences and fond memories of the lost historic ballpark.

Overall, this ceremony is just another example of the power that place and architecture have in our society. Like a living form, architecture, and more notably the ballpark, is preserved and mourned for like a family relative. Yet, when you expand the definition of family relative, the ballpark seamlessly fits in, and that is exactly why we preserve them.

Friends of Civic Stadium
For further information about the Friends of Civic Stadium please visit their website. They are currently collaborating with the Eugene Civic Alliance, the current owners of Civic Stadium and its property, in preserving the historical and cultural significance of Civic Stadium through alternative forms of preservation given its unfortunate fate.

Written by Brandon J. Grilc, Preservation Specialist

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