Tag Archives: building enclosure

Recycling Steel Windows: Is there a process?

PMA is leading the discussion to find a process to recycle steel windows.

Through our work of existing building restoration, PMA often encounters older properties with original steel windows. And more likely than not, we receive a request from the property Owner to upgrade those existing steel windows. Rarely does the request result from degradation or damage of the window system. Most often the Owners desire thermal and energy improvements.In order to achieve the desired improvements, while meeting code upgrades and other tenant improvements, replacement of the original steel windows is often the option of choice. And that is when the difficulty of recycling existing steel windows begins.
existing-steel-windows
STEEL WINDOWS 1920s – 1940s
In the 1920s through 1940s, there were a number of local and national steel window manufacturers. Steel windows were the preferred window system in both commercial and industrial buildings because of the simplicity of components, ease of installation, availability of product, size of window openings, and affordability of the product. Steel windows from every manufacturer typically used the same readily available extruded steel bar profiles: the “T” & “h” cross sections. The entire window assembly is characteristically composed of three materials: the frame, the glass, and glazing compound. Operable windows have added hardware. The steel sections of historic windows are still in use on today’s steel windows.

With such sparsity of components, and availability of an industrial steel recycling industry, why are steel windows not recycled? The answer is hazardous materials: lead paint and asbestos containing putty. Creating clean steel for recycling involves a two-step process. Once removed from the building, the steel windows must have the glass and glazing removed and the paint removed. Both the glazing and the paint must be disposed following hazardous material regulations. And that is the primary block to recycling. There are very few business established to remove hazardous waste from windows.
typical-steel-windows
CURRENT INDUSTRIAL PRACTICES
However, if we look at two current industrial practices, wood window restoration and carpet tile manufacturing, there is a basis for introduction of steel window recycling. Wood window restoration processes include the removal of lead paint and asbestos containing glazing putty. The industry has the capacity to use dipping tanks to remove the paint and putty on a large quantity of windows and then properly dispose of the waste. Modify the existing process to accommodate steel windows could be readily achievable. Manufacturers of carpet tiles revolutionized the industry by owning the recycling process from cradle to grave. Carpet tile manufacturers take back the tiles they manufactured for recycling and reuse. Steel window manufactures could do the same.

Currently steel window manufacturers purchase the cross sections from steel producers and do not become involved in the life span of the products they produce. If the steel window industry reassessed and evaluated their role in sustainable products, an opportunity to recycle existing steel windows would become available.

Here at Peter Meijer Architect, we are committed to lead the discussion with the design, build, and manufacturing community to find an economical solution to recycling steel windows. We believe that existing industries can be adapted to keep steel windows out of the waste stream and better utilize existing resources for reuse.

Written by Peter Meijer, AIA, NCARB / Principal

Studio Building Window Replacement

PMA provided planning and building science services for TMT Development’s project at the Studio Building in downtown Portland. The Studio Building is a twentieth century Baroque-style building built in 1927 by Ellison-White Conservatory and designed by locally renowned architect Luther Lee Dougan. Over time, the Studio Building has undergone multiple changes including new openings (1940), the addition of a new marquee (1956), and the construction of a new front entrance (2002) to name a few.

PMA lead the project teams Type III Design Review application for the replacement of windows on the building. After assessing the existing 192 historic steel windows, we recommended replacement windows to match the historic windows in style and size, and to fit within the existing window openings on all elevations. Drawings created during the assessment were used as part of the Type III Design Review application, as part of the pre-hearing review packet, and as part of the power-point presentation during the hearing in front of the Design Commission.

Presenting on Field Observations of Masonry Failures

Last month the Portland Chapter of RCI- a local chapter of the international association of professionals that specialize in the “specification and design of roofing, waterproofing and building envelope systems” (RCI PDX) hosted a two-day Education Symposium focused on Exterior Walls Quality Assurance & Building Envelope Presentations. The first day of the symposium was geared towards industry professionals “interested in performing observation to assure that exterior wall systems are installed in accordance with construction documents. The program covered diverse topics in the construction of exterior walls, and was intended for manufacturers, general contractors, quality assurance observers, and field inspectors.” (RCI PDX) While the second day was dedicated to Building Envelope Presentations. In addition to attending the first day of the symposium, Peter R. Meijer, AIA, NCARB, and Hali Knight presented on: When the Field Report of Masonry Does Not Correlate with Lab Results. Grant High School was the case study.

PPS-GH-2017-002

At the request of PPS, we provided a limited exterior condition assessment and interior historic evaluation of Grant High School. For the past 15+ 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.

Before our assessment, it was hypothesized that 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.

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; 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. 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.

TESTING AND 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.

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.

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.

CONCLUSIONS
Field observations of masonry failures can lead to incorrect diagnosis of the source of the problem. It is critical to conduct advanced laboratory analysis of material composition in order to correctly deduce the known failure mechanisms. If the cause of the failure is from defective material or defective manufacturing, steps could be taken to slow the deterioration or eliminate the cause of the deterioration without compromising the original material.

Written by Peter Meijer, AIA, NCARB / Principal

Analysis: Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

DOCOMOMO_OREGON and the Northwest Chapter of the Association for Preservation Technology recently held an Energy Conservation Symposium that explored issues facing mid-century modern buildings: How can modern historic buildings comply with today’s energy conservation standards? Is it possible to maintain the integrity of the historic building materials and aesthetics while also meeting new energy conservation requirements?

At PMA we believe that while challenging, it is possible to maintain the integrity of these historic mid-century modern buildings and meet new energy conservation requirements. In an effort to explore this possibility, we submitted an abstract for the symposium, and Halla Hoffer, AIA, subsequently presented on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures.

BACKGROUND
Effective daylighting can reduce both lighting and cooling loads while improving user comfort, satisfaction, and health. Despite plentiful glass, using daylight in mid-century modern building can be challenging. Glare and uneven light distribution can cause user discomfort and pose challenges to effectively daylighting spaces. Frequently, artificial lighting is used to balance lighting in spaces over lit by the sun, negating any potential energy savings. For existing buildings, the available methods to provide effective daylighting are limited by the existing constructions and configuration. To both preserve existing structures and provide ample daylight a critical question must be answered – what are the best practices for improving daylight in existing buildings? This study provides insight to daylighting existing structures, specifically, how light can be controlled and distributed in mid-century modern buildings with plentiful glazing.

1963 RESIDENTIAL TOWER
This study explores and analyzes how common daylighting strategies can be implemented on existing mid-century modern structures. The study focuses on a sixteen-story 1963 residential tower in Portland, Oregon, and explores how interior reflectivity, interior/exterior light shelves, shading, and glazing can impact daylight availability and distribution. The study looks at a variety of ways each strategy can be implemented and analyzes the results to determine best practices based on daylight distribution/availability, glare, lighting loads, and heating/cooling loads.
on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

TOOLS USED FOR SPECIFIC ANALYSIS
Emerging tools and technologies provide effective methods of analyzing hundreds of different daylighting simulations. Applications such as Grasshopper and Dynamo, which are visual programming environments for Rhinoceros 3D and Revit respectively, allow users to explore a variety of different design interventions and determine optimal solutions. Prior to starting the daylight analysis, we began with a “base geometry” of the existing conditions that we modeled in Rhinoceros 3D. We then developed a Grasshopper file to create daylighting interventions. For this study the interventions consisted of interior light shelves and exterior shading devices based on numerical inputs for shelf depth and height. Using Grasshopper in lieu of traditional 3D modeling allowed us to systematically test multiple variations of intervention geometry. In addition to studying how new geometries would impact daylighting we also studied how existing/new materials could impact daylighting performance.
on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

The daylighting analysis was performed using DIVA for Rhino, a plug-in that performs daylighting and energy analysis directly in Rhino. DIVA also offers several Grasshopper nodes, allowing the analysis to be controlled and managed directly in Grasshopper. For this analysis the primary results we extracted and used to measure performance included:

Annual Daylight: Percentage of time space receives at least 300 lux. This value can be mapped over the area under analysis. Typically, areas that receive 300 lux at least 50% of the time have the potential for daylighting.

Spatial Daylight Autonomy (sDA): Percentage of a space that receives 300 lux for at least 50% of the annual occupied hours. This metric provides a single number for quickly determining daylight potential. A value over 55 indicates that daylighting will be at a minimum nominally accepted by occupants. A value over 75 denotes a space where daylighting will likely be preferred by occupants.

Annual Sunlight Exposure (ASE): Percentage of a space that receives over 1,000 lux for at least 250 hours per year. High values indicate that the space may be overlit and cause glare/discomfort.

Daylight Factor: A ratio comparing light levels on the interior of the structure to the light levels on the exterior. Typically, a value under 2% indicates that the space cannot be adequately daylit, a value between 2%-5% is preferred for daylighting, and a value over 5% indicates that the space is well daylight, but may be overlit.

on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

CONCLUSIONS
Reflective interior surfaces can have a significant impact on daylight distribution.

Without any shading there is a high probability for glare according to ASE and DF values.

Interior light shelves alone can reduce the ASE values and the probability of glare.

Interior light shelves alone are not as effective as exterior shading devices in reducing glare.

A combination of reflective interior materials, interior light shelves, and exterior shading devices is the most effective method to provide adequate levels and even distribution of light.

Written and presented by Halla Hoffer, AIA, Assoc. DBIA / Associate

Abstract: Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

When we think of energy conservation standards for our built environment an increasing amount of existing buildings do not comply with today’s standards. A large portion of these existing buildings are from the mid-century modern era. Additionally, mid-century modern buildings are approaching historic status, if not already there. This status compounds finding the best way to integrate current energy standards because aesthetic impacts to a historic resource must be kept to a minimum. At PMA we believe that while challenging, it is possible to maintain the integrity of historic mid-century modern buildings while meeting new energy conservation requirements. In an effort to explore this possibility, we have submitted an abstract for an upcoming Energy Conservation in Mid-Century Modern Buildings Symposium presented jointly by APT Northwest and DOCOMOMO_Oregon.
window-detail
ABSTRACT: BEST PRACTICES FOR PROVIDING EFFECTIVE DAYLIGHT IN MID-CENTURY MODERN STRUCTURES
Effective daylighting can reduce both lighting and cooling loads while improving user comfort, satisfaction, and health. Despite plentiful glass, using daylight in mid-century modern building can be challenging. Glare and uneven light distribution can cause user discomfort and pose challenges to effectively daylighting spaces. Frequently, artificial lighting is used to balance lighting in spaces over lit by the sun, negating any potential energy savings. For existing buildings, the available methods to provide effective daylighting are limited by the existing constructions and configuration. To both preserve existing structures and provide ample daylight a critical question must be answered – what are the best practices for improving daylight in existing buildings? This study provides insight to daylighting existing structures, specifically, how light can be controlled and distributed in mid-century modern buildings with plentiful glazing.

Emerging tools and technologies provide effective methods of analyzing hundreds of different daylighting simulations. Applications such as Grasshopper and Dynamo allow users to explore a variety of different design interventions and determine optimal solutions. This study explores and analyzes how common daylighting strategies can be implemented on existing mid-century modern structures. The study focuses on a 1963 residential tower in Portland, Oregon, and explores how interior reflectivity, interior/exterior light shelves, shading, and glazing can impact daylight availability and distribution. The study looks at a variety of ways each strategy can be implemented and analyzes the results to determine best practices based on daylight distribution/availability, glare, lighting loads, and heating/cooling loads.

Speaker Bio
Halla Hoffer, AIA, Assoc. DBIA
Associate / Peter Meijer Architect, PC

Halla is passionate about rehabilitating historic and existing architecture by integrating the latest energy technologies to maintain the structures inherent sustainability. Halla joined PMA in 2012 and was promoted to Associate in 2016. She is a specialist in energy and environmental management, as well as building science performance for civic, educational, and residential resources. Halla meets the Secretary of the Interior’s Historic Preservation Professional Qualification Standards (36 CFR Part 61).

Joseph Vance Building

At the request of Jonathan Rose Companies/Kidder Mathews, Peter Meijer Architect, PC, (PMA) was retained to provide a limited exterior condition assessment of the terra cotta veneer at the Joseph Vance Building in Seattle, WA. PMA was initially contracted to observe repair work being performed by Pioneer Masonry Restoration (Pioneer). While onsite several significant deficiencies were noted on the west elevation. PMA recommended a complete assessment of the west elevation to understand the source of the observed deficiencies. Exterior observations were conducted from swing stage equipment located on the west elevation of the building. The south elevation was observed during review of Pioneer’s repair work and is discussed in the following report, however detailed observations on the elevation were not included in this scope of work. The short east elevation was also not assessed as part of this investigation. The purpose of the assessment was to provide Jonathan Rose Companies/Kidder Mathews with an understanding of the existing conditions, potential causes of terra cotta deterioration and repair recommendations.

The Joseph Vance Building was built in 1929 .The building is fourteen stories high and constructed with a concrete structure and concrete infill between structural columns. The west and south elevations have a decorative terra cotta veneer facade. On the east elevation the primary material is painted concrete/stucco, with a small section of terra cotta veneer along the southern most portion of the structure. The north elevation is entirely painted concrete/stucco.

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.
WSU-PMAPDX_masonry_sealers
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.

WSU-PMAPDX_masonry_sealers_002
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.
WSU-PMAPDX_masonry_sealers-004
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.
wufi-isopleths-results-wsu
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

Trinity Episcopal Cathedral Seismic Rehabilitation

Trinity Episcopal Cathedral was constructed ca. 1904 in the Gothic Revival Style. PMA was the historic architect on the design team tasked with conducting an exterior assessment including conditions of the slate roof, flashing system, stone veneer, and other details.

In addition, PMA studied the passive ventilation potential of the sanctuary in order to improve the space for the maximum number of occupants with the minimal cost and changes for the congregation. 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. PMA developed an energy model using OpenStudio and EnergyPlus to compare the thermal comfort of occupants within the space. The study focused on the thermal comfort within the Sanctuary, and results showed natural ventilation could dramatically lower indoor temperatures during peak summer months.

Means and Methods of Architectural Design

On a recent trip to Italy, I couldn’t help but contemplate the progression of architecture styles across time and contemporary architecture’s divergence/evolution from past practice. Architecture, alongside art, has long reflected contemporary trends, culture, and politics. More than ever, contemporary architecture reflects our societies’ obsession with technology, efficiency, and value-engineering. As I stood within the walls of Carlos Scarpa’s Brion Cemetery, taking in the attention to detail and crafted experience of the space, I wondered if architecture would ever return to this level of craft, detail, and whimsy. It is hard to image Carlos Scarpa’s intricate and unique detail being created in the architectural world today. From my perception, the art of architecture on a mass scale is being transformed to a systems and science of architecture where unique, non-functioning, artful details are being abandoned as superfluous and cost prohibited.
Means-Methods-Architectural-Design-001
A Paradigm Shift
Great works of historic architecture were conceived by pen and paper as artistic minds envisioned each space on iterative gestural pages; translated from enigmas to sketches to drawings to reality. Materials were crafted by hand and details seamlessly integrated within each trade’s identity. Today’s paradigm shift toward Building Information Modeling (BIM), factory production, and intelligent building systems have transformed the means and methods of the tradition discipline. Traditional detailing known by each trade has been lost to time as architects and builders move to new systems. The design process has continued to evolve and transitioned to computer based iterative processes. This creates a new dialog where the computer program itself has an influence over the design.

Architectural contemporary styles are named for the processes in which they were designed, such as Diagramism, Revitism, Scriptism, and Subdivisionism. These processes include designing in CAD, BIM, and other 3D programs, which can predominantly drive the design style and form. Architects and designers need to be aware of how architectural design is affected by each program’s restrictions and work flow tendencies. There can be a detachment for the final goal of the built form as we go down the virtual rabbit hole. The benefit of 3D modeling is that it allows designers to more fully comprehend form and its intersection with the overall building systems. However, if the design process is pushed into modeling without a strong concept, the objective can be easily replaced with creating a well-organized and systematic Building Information Modeling, instead of holistic architectural design.
Means-Methods-Architectural-Design-002
Architectural Design and BIM
BIM designs are based primarily of component systems that create efficient, intelligent, and informative models. Designers can easily draw schedules and quantities that greatly speed up processes, however in the design process, focusing on components can also create a disassociation from the whole building and design concept. The translation of an artistic gesture of a material or space can easily be lost in the clunky world of 3D representation and restrictions.

I am certainly a proponent of BIM, but I am also an advocate of preserving the art and craft of architecture. BIM is a terrific for understanding buildings in their 3D form as a composition of components and systems. BIM’s intelligence allows for continued updating of schedules and quantities, allowing for time efficiency. However, these components are limited to the software’s modeling options and the designer’s skill at modeling. The virtual world is still not an accurate representation of all the properties of building materials or their structural capabilities. In other words, BIM cannot be a means from the start to the end. Our profession is obligated to continue to push for high design standards and syndicate and extrapolate. I continue to see architecture that either allows BIM to drive design or prioritizes efficiency and value-engineering over quality of design. As BIM evolves within architecture as a means to design, I hope it can assist designers in their creative process and challenge our profession’s boundaries.

Written by Hali Knight, Architect I

Sources
Prospect Magazine
Archdaily
DI