Tag Archives: oregon

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

Assessing a Historic House in Springfield, Oregon

Owning, maintaining, and providing active use within a single family settlement era house is not a typical mission for a public parks agency. One such property is the Reynold & Eva Briggs House located in the northeast corner of the Dorris Ranch Living History Farm, in Springfield, Oregon, currently stewarded by Willamalane Parks and Recreation District (WPRD). Compounding the unusual situation is that the area is a historic site, a working farm, and a public park. In addition the property’s history, age, material, and conditions of the house add further complexity to the stewardship role. In order to guide the WPRD with long-range decisions regarding the Briggs House, the District sought an up to date exterior and interior condition assessment and potential rehabilitation options in support of current and future park programming needs, including as a source of income derived from continued residential use. The Briggs House has not been occupied since its last resident left in 2009.
Briggs-House

THE ASSESSMENT
The property, The Dorris Ranch Living History Farm, was listed as a National Register of Historic Places Historic District on June 22, 1988. While the Briggs House is located on the ranch property, it sits outside the boundaries of the historic district.

As researched by University of Oregon historic preservation students, the settlement era house is one of the five oldest houses in the Springfield area and one of the city’s few remaining examples of box construction from the Homestead era. The oldest portion of the house—the two-story volume and its eastern wing—was originally constructed by George Thurston in 1872, and later served as the home of caretakers Reynold and Eva Briggs. Once vernacular in the Willamette Valley, the house exhibits a Gothic-influenced upright-and-wing style of construction and was expanded in the 1890’s to accommodate the changing needs of its residents.

Typical of early homestead sites, the Briggs House was constructed without a foundation. The original substructure that continues to support the house consists of partially hewn wood posts on stone piers set directly on the ground surface. Utilizing the box-construction method, 1-inch by 11-inch boards were set vertically and connected to the 7-inch by 9-inch sill plate and ledger plate above the posts to create a “box” form without the use of other framing members. Two-inch by 4-inch roof rafters were then set above the top ledger plates. Floor joists, the original board-and-battens wall siding, and roof panels were added to the house after its basic skeletal structure had been completed. The original wall siding was replaced with weatherboards at an unknown date. Portions of this siding were later replaced with shiplap in the 1890’s, and the entire exterior was later covered with T-111 siding in the 1970’s.
Briggs-House

REHABILITATION CHALLENGES
After discussing the main program activities that take place on Dorris Ranch with Willamalane Parks and Recreation District staff, PMA recognized the primary challenge to any rehabilitation options was the balance between maintaining the historic character of the house and meeting all the code requirements mandated by a rehabilitation, including public access, universal access, and mechanical, electrical, energy, and plumbing upgrades. Previous studies undertaken by Restore Oregon on similar settlement era houses indicated that a balance must be reached between preserving the essence of the house while changing and modifying other portions of the house and property to achieve programming needs. Complicating the Briggs House options are siting of the house within an active area of the park, the two story volume, the lack of an adequate structural foundation, and accommodating large classroom needs within original tiny floor plans. Every room of the historic property has an established spatial function and are tiny in size. Any rehabilitation option must consider that all rooms in the house would be “flexible” and be used as needed for a variety of purposes.

THE POTENTIAL ROLE OF HISTORIC STATUS
Willamalane Parks and Recreation District currently stewards the Briggs House as a historic property by maintaining and protecting the property from encroachment by nature, animal and pest infestation, and unsafe use by park visitors. Inclusion of the property within the district as a contributing resource has both pro and con impacts. Inclusion within an expanded boundary of the current National Register Dorris Ranch Historic District could prove beneficial in finding financial sources to help with a rehabilitation although the available funds are likely insignificant when evaluated against the full cost required to upgrade the Briggs house to a public structure. On the other hand, including the property in the district may prove problematic for WPRD as it may limit, or make more difficult, viable and creative rehabilitation options that would not be approved by the local jurisdiction having authority.
Briggs-House

It is generally agreed that house museums (properties that are preserved as homes to be visited by the public) are not financially prudent uses to retain historic properties. Recent studies conclude that a compromise must occur between balancing original historic character with up to date and flexible programming space to achieve viable long-term solutions for unique homestead-era properties.

Written By Marion Rosas / Designer and Peter Meijer, AIA, NCARB / Principal

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.
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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).

Preservation Month 2017

May is Preservation Month! Review ten (10) handy preservation resources:

ONE – We explore some factors and opinions on new construction in Historic Districts.
PMAPDX OSU Buildable Landarea

TWO – An iconic example of a landmarked building less than 50 years old.
portland-building-pmapdx-nomination

THREE – Visit Oregon’s SHPO website to browse historic sites, NR listings, & available grants.
Union Station Historic/Seismic Renovation

FOUR – Get to know your local architectural styles from the 1840s – 1970s.
Hillsboro J-B House

FIVE – Pledge your support for a rehabilitated VMC because this place matters.

SIX – How you can find a historic place in the state of Washington.
PMAPDX-planning

SEVEN – Tax Incentives for Preserving Historic Properties.
USCH Courtyard

EIGHT – Oregon’s Most Endangered Places via Restore Oregon.
PMAPDX modern survey historic photo

NINE – Keeping It Modern. An architectural conservation grants for 20th century buildings.

TEN – How Historic Preservation is Reviving America’s Communities.
Hillsboro_OrencoInventory

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.
Picture1-gresham-styles-presentation

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.

overview-architecture-styles-oregon-peter-meijer-architect

overview-architecture-styles-oregon-peter-meijer-architect

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.
pmapdx-lighting-design-004
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.

pmapdx-lighting-design-002
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.

pmapdx-lighting-design-001
pmapdx-lighting-design-003
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.

State and Federal Historic Preservation Incentives Available in Oregon

Historic Preservation Incentives at the State and Federal level are either tax incentives or grants. PMA keeps up to date regarding these programs as incentives are ever-changing and apt to suddenly sunset or be revised. Following is a brief explanation of incentives offered by state or federal government or private agencies as of 2016. PMA has worked with multiple owners and agencies across the Pacific Northwest to take advantage of state and federal tax incentive programs, and we can provide expert experience in the latest interpretations of work that meets the standards for these incentives. A few other redevelopment incentive programs are also mentioned below, if they have been successfully combined with historic preservation incentive programs in Oregon.
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FEDERAL AND STATE OF OREGON TAX INCENTIVES

Oregon Special Assessment

Properties contributing to a district or individually listed on the National Register and in need of some rehabilitation are eligible for the State of Oregon Special Assessment property tax incentive. Property taxes are “frozen” at the time of application and are held at that value for 10 years. During this time period owners may make significant investments in the property without an increase in assessed value. The earlier the investment is made and the larger the resulting increase in market value, the greater the benefit to the owner.

A Preservation Plan must be submitted, outlining the rehabilitation work proposed. Exterior work is prioritized, and the work must meet the Secretary of the Interior’s Standards for Rehabilitation. The total valuation of work must be at least 10% of the property’s Real market value and that amount must be spent in the first five years of the special assessment period.

A second term of 10 years is available, with some limitations on the types of preservation work that are eligible for the program. Eligible work includes energy conservation projects, ADA compliance, seismic improvements, or sustainability. The investment must meet or exceed 10% of the Real market value of the property at the time of application.

Non-contributing properties in need of rehabilitation could be eligible for the State of Oregon Special Assessment property tax incentive, if it is determined by the State Historic Preservation Office (SHPO) that the property is or would be eligible for listing on the National Register, and that the renovation would restore obscured or missing historic character.

Federal Historic Tax Credit Incentives (HTC)

Rehabilitation tax credits, in the amount of up to 20% of the amount spent on the project, are available to qualifying projects.

Property must be listed either individually or as a contributing property to a historic district listed in the National Register. Alternately, to qualify for up to 10% in tax credits, a non-designated building must have been constructed before 1936.

Property must be income-producing for at least 5 years after rehabilitation. Owner-occupied residential projects such as condominiums do not qualify, but apartments or mixed-use projects are eligible. The project must be substantial. The owner must spend more on rehabilitation expenditures than the “adjusted basis” value of the property. The Investment Tax Credit does not include the purchase price of the property.

Rehabilitation work must meet certain standards for preservation. These are the Secretary of the Interior’s Standards for Rehabilitation.

gus-solomon-interior-courtroom

Federal Preservation Easement Tax Deduction
A preservation easement is a legal agreement to protect a historic property from changes, including neglect. The property must be individually listed on the NRHP or a contributing structure within a National Register-listed historic district or local historic district. If a property owner makes a voluntary donation to a trust such as the Historic Preservation League of Oregon (HPLO) of all or a portion of a property, the donation can qualify as a charitable tax donation. Only some of the rights associated with the property are being donated, and the donation permanently limits uses or changes as specified. The owner of the historic property may still use the property, and must maintain it. The owner may sell the property, but the restrictions will remain with the property. The preservation easement may be structured to include only the exterior of a building, or may include air rights, interiors, grounds, or other features.

OTHER INCENTIVES OR PROGRAMS

Private and Public Grants
Grants for historic preservation work vary widely as to eligibility rules, requirements, and amounts. While private-sector grant-making organizations are more apt to change grant programs or requirements year-to-year, they also are more likely to provide larger sums of money. Historic preservation grants are sometimes only available for preservation planning, survey, or designation work as opposed to “brick and mortar” projects.

The State Historic Preservation Office (SHPO) administers Federal grants directly to local government entities through the Certified Local Government (CLG) program. The SHPO also administers State grants through the Oregon Heritage Grants, Oregon Museums Grants, Preserving Oregon Grants, Diamonds in the Rough Grants, and Oregon Historic Cemeteries Grants. These are all competitive and offer relatively modest amounts of funding.

New Market Tax Credit
In December 2015, Congress approved an extension of the New Market Tax Credit (NMTC) program through 2019. There is an immediate opportunity for investors, low-income communities, and businesses to use this successful program in order to revitalize economically distressed areas and create jobs. The State also runs the Oregon New Market Tax Credit program, which is modeled on the same requirements as the Federal program.

The Blanchet House of Hospitality, a new (2012) building in a historic district in downtown Portland, used New Markets Tax Credits. NMTC and HTC have also been used together, such as in the Mercy Corps restoration/ expansion in the Skidmore Old Town historic district.
The NMTC is not available for loans or investments in projects involving residential rental housing alone, but may be used for mixed-use and some other housing projects. Investments must be made to designated Community Development Entities (CDEs), which in turn provide investments in low-income communities. The investment is claimed over a 7-year credit allowance period.

Low-Income Housing Tax Credits
The federal government allots a certain amount per state per year to be awarded to developers willing to provide low income housing. Residential rental properties only may qualify for the Low-Income Housing Tax Credits (LIHTC) program. A certain percentage of the units must be restricted to occupants making 50% or less (or 60% or less) of local median income, and the affordability restrictions must be maintained for a minimum of 30 years. LIHTC has been successfully combined with HTC in downtown Portland projects such as the Admiral Apartments, the Martha Washington, and the Bronaugh Apartments.

Written by Kristen Minor, Associate/Preservation Planner

Local Historic Preservation Incentives Available in Portland, Oregon

With a firm comprised of architects and planners, we understand and assist owners and developers navigate local historic preservation incentives made available by the City of Portland. The following is a comprehensive overview of incentives offered by the City, as of 2016, in the form of various use allowances, development rules “waivers,” and opportunities to transfer allowed but unused floor area to other property owners, creating an opportunity for a monetary benefit. We grouped the available historic preservation incentives available by the following: City of Portland Incentives, City of Portland/State of Oregon Building Code Allowances, and Portland Development Commission Programs.

The City of Portland’s Central City 2035 Plan (as well as other related City code projects) are currently under review. The Proposed Draft was published in June 2016 and is being reviewed by many City and non-City agencies, bureaus, and organizations. Proposed changes directly affect portions of the Portland Zoning Code, but the existing Zoning Code will remain in effect until adoption of the final Central City 2035 Plan, probably in late 2018. Increased transfer options are the major change proposed.

“Landmark” as defined by the City is a property individually listed on the National Register, or evaluated by the City of Portland as a local historic resource. Many incentives are also available to resources designated contributing to a National Register-listed Historic District or locally designated Conservation District.

Marshall Wells Lofts building preservation plan.

CITY OF PORTLAND INCENTIVES
Additional density in Single-Dwelling zones. Landmarks in Single-Dwelling zones may be used as multi-dwelling structures, up to a maximum of one dwelling unit for each 1,000 square feet of site area. No additional off-street parking is required, but the existing number of off-street parking spaces must be retained. The landmark may be expanded and the new floor area used for additional dwelling units only if the expansion is approved through historic design review.

Additional density in Multi-Dwelling zones. Landmarks and contributing structures in historic districts located in multi-dwelling zones may be used as multi-dwelling structures, with no maximum density. No additional off-street parking is required, but the existing number of off-street parking spaces must be retained. The building may be expanded and the new floor area used for additional dwelling units only if the expansion is approved through historic design review.

Nonresidential uses in the RX zone. In the RX zone, except on certain sites which directly front on the Park Blocks, up to 100 percent of the floor area of a landmark or contributing structure may be approved for Retail Sales and Service, Office, Major Event Entertainment, or Manufacturing and Production uses through Historic Preservation Incentive Review.

Nonresidential uses in the RH, R1 and R2 zones. In the RH, R1 and R2 zones, up to 100 percent of the floor area of a landmark or contributing structure may be approved for Retail Sales and Service, Office, or Manufacturing and Production uses as follows:

a. Review required. The nonresidential uses must be approved through Historic Preservation Incentive Review; and

b. Previous nonresidential use required. The last use in the structure must have been in a nonresidential use category and have been allowed when established; if part of the structure was in residential use, the proposal must include at least as many dwelling units as were part of the last allowed use or uses. If the last allowed use was residential only, the structure is not eligible for this incentive.

Daycare is an allowed use in all residential zones in historic landmark or contributing structures. In non-historic structures, daycare uses in residential zones other than RX require a conditional use review.

Conditional uses in Residential, Commercial, and Employment zones. In these zones, applications for conditional uses at landmarks or contributing structures are processed through a Type II procedure, rather than the longer Type III procedure requiring a public hearing.

Exemption from minimum density. Minimum housing density regulations do not apply in landmarks or contributing structures.

Crane building historic consulting for storefront updates.

Commercial allowances in Central City Industrial zones. National Register-listed properties or those contributing to a National Register-listed historic district have potential to include office and retail uses.

Commercial allowances in employment and industrial zones. Office and retail uses are allowed in landmarks in areas where those uses are otherwise restricted.

Increased maximum parking ratios in Central City. National Register-listed properties or those contributing to a National Register-listed historic district within the Central City Core parking area are allowed to increase parking ratios.

Commercial allowances in Guild’s Lake Industrial Sanctuary District. Increases allowances for office and retail uses in landmarks in an area where non-industrial uses are otherwise restricted.

The transfer of density and floor area ratio (FAR) from a landmark to another location is allowed in Multi-Dwelling, Commercial, and Employment zones. Historic properties with unused development “potential” therefore may find a market for the FAR.

Proposed Development transfer opportunities (potentially adopted in 2018):
Landmarks and contributing resources in historic districts will be able to transfer FAR City-wide, as long as the “sending” resource meets seismic reinforcement standards. Seismic work may be allowable in phases over a period of years. FAR to be transferred is not only the base amount unused by the existing historic structure, but also an additional 3:1.

U.S. Custom House renovation and historic tax credits.

PORTLAND DEVELOPMENT COMMISSION PROGRAMS
The Portland Development Commission (PDC) has operated several programs to benefit owners of existing buildings (not necessarily historic buildings). These programs have been suspended and will be replaced by the Prosperity Investment Program (PIP). Information about the PIP is not yet available, but the program may still provide benefits to owners, similar to the suspended Storefront Improvement Program.

For further information on how PMA helps owners consider reuse options, navigate the regulations, and take advantage of available benefits – please visit our website to review our multidisciplinary projects and comprehensive architecture, building envelope science, and planning services.

Written by Kristen Minor, Associate, Preservation Planner

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