Black EPDM Roofing Helps Multifamily Buildings Achieve the Passive House Standard

Two years ago, the three low-rise apartment buildings at the intersection of Southern Avenue and Benning Road in Washington, D.C., stood derelict and abandoned, uninhabitable reminders of 1960s brick and block construction. Today, the buildings—now known as Weinberg Commons—represent a landmark effort to provide clean, secure and energy-efficient shelter to low-income families. For the scores of people—architects, energy consultants, contractors and experts in housing finance, to name a few—who helped repurpose Weinberg Commons and bring it back to life, this project represents an unparalleled achievement in retrofitting. For the families who now live here, it means a giant step toward a more secure future.

Thermal conductivity, air infiltration and exfiltration, and solar gain were important to the team working on Weinberg Commons

Thermal conductivity, air infiltration and exfiltration, and solar gain were important to the team working on Weinberg Commons.

One of the keys to that secure future will be very low or no energy bills. From the beginning, the team that oversaw the retrofitting of these buildings, each with almost 8,000 square feet of rentable space, was committed to ensuring that all three would show greatly reduced energy use and at least one would achieve Passive House (PH) certification.

The criteria to become a passive structure are rigorous and focus on three specific design elements to reduce energy. (The requirements and certification observed by the Weinberg Commons team are set by Chicago-based PHIUS, the Passive House Institute U.S.)

The first requirement is airtightness to ensure the building minimizes the amount of heated or cooled air it loses (0.6 air changes per hour at 50 Pascals of pressure).

Second, a Passive House cannot use more than 4.75 kBtu per square foot per year. This is specific heating energy demand (or cooling in cooling climates).

The third requirement caps the peak total amount of energy the heating and cooling system and appliances in the building can use per year, including domestic hot water, lighting and plug loads. It cannot exceed 38 kBtu per square foot per year.

three low-rise apartment buildings at the intersection of Southern Avenue and Benning Road in Washington, D.C., stood derelict and abandoned, uninhabitable reminders of 1960s brick and block construction.

Three low-rise apartment buildings at the intersection of Southern Avenue and Benning Road in Washington, D.C., stood derelict and abandoned, uninhabitable reminders of 1960s brick and block construction.

Michael Hindle, a Baltimore-based Certified Passive House Consultant who is current president of the Passive House Alliance U.S. Board of Managers, helped with the retrofit design of Weinberg Commons. (Passive House Alliance U.S. is a PHIUS program designed to advance passive building.) He points out these three pass/fail criteria are measures of success, not design principles to help a team achieve the energy savings that lead to PH certification. However, Hindle highlights five design principles have been identified as important guides in the design of Passive House projects:

  • Continuous insulation through the building’s entire envelope without any thermal bridging.
  • An extremely tight building envelope, preventing infiltration of outside air and loss of conditioned air.
  • High-performance windows and doors, typically triple-paned.
  • Balanced heat- and moisture-recovery ventilation and a minimal space-conditioning system.
  • Solar gain is optimized to exploit the sun’s energy for heating purposes and minimize it in cooling seasons.

Although only one building at Weinberg Commons has achieved PH certification, all three buildings were designed to the exact same specifications and technically could be PH certified as long as the rigorous airtightness threshold is met. Several factors influenced the decision, made at the outset of the project, to focus on just one building for PH certification. The design team’s perception was that airtightness would be the most challenging aspect for the contractor. Matt Fine, an architect with Zavos Architecture & Design, Frederick, Md., who led the project, explains: “The intention was to proceed with the first building, test its airtightness and improve on that scope of work for the next building. Repeat, refine and finally apply to the third sequential building.”

Fine points out the first two buildings actually achieved “super” airtightness results relative to any new-construction project built today but did not cross the 0.6 air changes per hour at 50 Pascals of pressure threshold of Passive House. Given the budget-conscious nature of the Weinberg Commons project, resealing and retesting of the first two buildings was not an option for the team, but lessons learned from these two buildings were applied to the retrofit of the third building. “In retrospect, all three buildings would have been able to meet the PH threshold with relatively little extra effort,” Fine says. “But the dynamics of construction sequencing, along with imposed schedules for occupancy, complicated our ability to be flexible with scope change once the contracts were executed and limited dollars were allocated.”

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The Roof Cover: The Cap on the Roof System

For nearly two years in this magazine, I have been discussing the various components that make up a roof system: roof deck, substrate boards, vapor/air retarder, insulation and cover boards (see “More from Hutch”, page 3). Although each component delivers its own unique benefit to the system, they are intended to work together. When designing a roofing system, components cannot be evaluated solely on their own and consideration must be taken for a holistic view of the system; all components must work together synergistically for sustainable performance. Unfortunately, I often have seen that when components are not designed to work within the system unintended consequences occur, such as a premature roof system failure. A roof system’s strength is only as good as its weakest link. The roof cover is the last component in the design of a durable, sustainable roof system—defined previously as being of long-term performance, which is the essence of sustainability.

This ballasted 90-mil EPDM roof was designed for 50 years of service life. All the roof-system components were designed to complement each other. The author has designed numerous ballasted EPDM roofs that are still in place providing service.

PHOTO 1: This ballasted 90-mil EPDM roof was designed for 50 years of service life. All the roof-system components
were designed to complement each other. The author has designed numerous ballasted EPDM roofs that are still in place providing service.

The roof cover for this article is defined as the waterproofing membrane outboard of the roof deck and all other roof-system components. It protects the system components from the effects of climate, rooftop use, foot traffic, bird and insect infestation, and animal husbandry. Without it, there is no roof, no protection and no safety. When mankind moved from cave dwellings to the open, the first thing early humans learned to construct was basic roof-cover protection. Thus, roof covers have been in existence since man’s earliest built environment.

WHAT CONSTITUTES AN APPROPRIATE ROOF COVER?

There is no one roof cover that is appropriate for all conditions and climates. It cannot be codified or prescribed, as many are trying to do, and cannot be randomly selected. I, and numerous other consultants, earn a good living investigating roof failures that result from inappropriate roof-cover and system component selection.

There are several criteria for roof-cover selection, such as:

  • Compatibility with selected adhesives and the substrate below.
  • Climate and geographic factors: seacoast, open plains, hills, mountains, snow, ice, hail, rainfall intensity, as well as micro-climates.
  • Compatibility with the effluent coming out of rooftop exhausts.
  • Local building-code requirements, such as R-value, fire and wind requirements.
  • Local contractors knowledgeable and experienced in its installation.
  • Roof use: Will it be just a roof or have some other use, such as supporting daily foot traffic to examine ammonia lines or have fork lifts driven over it?
  • Building geometry: Can the selected roof cover be installed with success or does the building’s configuration work against you?
  • Building occupancy, relative humidity, interior temperature management, building envelope system, interior building pressure management.
  • Building structural systems that support the enclosure.
  • Interfaces with the adjacent building systems.
  • Environmental, energy conservation and related local code/jurisdictional factors.
  • Delivering on the expectations of the building owner: Is it a LEED building? Does he/she want to go above and beyond roof insulation thermal-value requirements to achieve even better energy savings? Is he/she going to sell the building in the near future?

ROOF-COVER TYPES

There are many types of roof-cover options for the designer. Wood, stone, asphalt, tile, metal, reed, thatch, skins, mud and concrete are all roof covers used around the world in steep-slope applications. This article will examine the low-slope materials.

The dominant roof covers in the low-slope roof market are:

    Thermoset: EPDM

  • Roof sheets joined via tape and adhesive
  • Installed: mechanically fastened, fully adhered or ballasted
  • Thermoplastic: TPO or PVC

  • Roof sheets joined via heat welding
  • Installed: mechanically fastened, fully adhered or plate-bonded (often referred to as the “RhinoBond System”)
  • Asphaltic: modified bitumen

  • Installed in hot asphalt, cold adhesive or torch application
  • EPDM (ETHYLENE PROPYLENE DIENE MONOMER)

    Fully adhered EPDM on this high school in the Chicago suburbs is placed over a cover board, which provides a high degree of protection from hail and foot traffic.

    PHOTO 2: Fully adhered EPDM on this high school in the Chicago suburbs is placed over a cover board, which provides a high degree of protection from hail and foot traffic.


    EPDM is produced in three thicknesses— 45, 60 and 90 mil—with and without reinforcing. It can be procured with a fleece backing in traditional black or with a white laminate on top. The lap seams are typically bonded with seam tape and primer.

    EPDM has a 40-year history of performance; I have 30-year-old EPDM roof systems that I have designed that are still in place and still performing. Available in large sheets—up to 50-feet wide and 200-feet long—with factory-applied seam tape, installation can be very efficient. Fleece-back membrane and 90-mil product have superior hail and puncture resistance. Historical concerns with EPDM lap-seam failure revolved around liquid- applied splice adhesive; with seam tape technology this concern is virtually moot. Non-reinforced ballasted and mechanically fastened EPDM roof membrane can be recycled.

    EPDM can be installed as a ballasted, mechanically fastened or fully adhered system (see photos 1, 2 and 3). In my opinion, ballasted systems offer the greatest sustainability and energy-conservation potential. The majority of systems being installed today are fully adhered. Ballast lost its popularity when wind codes raised the concern of ballast coming off the roof in high-wind events. However, Clinton, Ohio-based RICOWI has observed through inspection that ballasted roofs performed well even in hurricane-prone locations when properly designed (see ANSI-SPRI RP4).

    PHOTOS: HUTCHINSON DESIGN GROUP LTD

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Coating Extends the Life of Aging Roofs

The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems.

The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems.

The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems. It includes a cleaner to prepare the substrate for priming; two primers to improve adhesion of the topcoat; a multipurpose sealant for use with reinforcement roofing fabric to complete repair and maintenance tasks; three topcoats—Silicone Roof Coating (available in white and gray), Silicone Masonry Wall Coating (available in white and gray) and Silicone Skylight Coating; and a cleaner to wash tools and equipment. All products are solvent-free and comply with VOC regulations throughout North America.

Research Helps Industry Organizations Conclude Ballasted Roofs Provide Energy Savings

During the last decade, the roofing industry has been increasingly impacted by two strong forces: first, rising energy prices with no real end in sight, and, second, increasingly stringent building codes and regulations, designed to limit emissions, reduce energy use and mitigate the impact of urban heat islands.

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007.

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007. PHOTO: EPDM Roofing Association

The industry response has also been two-fold: In some instances, new products have been created, such as lower VOC adhesives, primers and sealants, self-adhering membranes and a wider variety of reflective membranes. At the same time, roofing professionals have taken a close look at some of the products that have been in use for a generation. Using rigorous science, they have tested these tried-and-true products to see how they measure up against the new standards. And in many cases, they’ve found that products that have been in use for decades are delivering great results in this new, energy-sensitive environment. Case in point: ballasted roofing, which has been available since the early 1970s, is turning out to be a great choice to meet 21st century needs.

2007 Study

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007. Andre Desjarlais, ORNL’s group leader of Building Envelope Research, and his colleagues had just completed work in which “we had done a fairly substantial comparison of different cool roof technologies, both membrane types, as well as coatings,” Desjarlais says. At the request of EPDM manufacturers, working together at the newly founded EPDM Roofing Association (ERA), Bethesda, Md., as well as manufacturers within Waltham, Mass.-based SPRI, Desjarlais designed and implemented a second study to assess the performance of ballasted roofing. “We undertook a study to effectively expand what we had done earlier on coatings and membranes,” he says.

Other factors also encouraged ORNL to generate data about ballasted roofing. The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings. Desjarlais believed this definition of a “cool roof” might be inaccurately limiting roofing choice by excluding other roofing materials, such as ballasted roofs, that would deliver comparable savings.

The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings.

The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings. PHOTO: EPDM Roofing Association

In addition, in Chicago, a new Chicago Energy Code was adopted as early as 2001 “with high reflectivity and emissivity requirements that limited severely building owners’ and managers’ roof system choices”, according to a paper presented in 2011 by Bill McHugh of the Chicago Roofing Contractors Association. At the roofing industry’s request, a reprieve was granted, giving the industry until 2009 to come up with products with a reflectivity of 0.25.

Faced with that 2009 deadline, the Chicagoland Roofing Council, Chicago Roofing Contractors Association and Rosemont, Ill.-based National Roofing Contractors Association began in 2001 to conduct research on products that would help to meet the city’s goal of creating a workable Urban Heat Island Effect Ordinance while giving building owners a wider choice of roofing products. As part of their effort, the industry coalition turned its attention to the energy-saving qualities of ballasted roofing and coordinated its work with the research at ORNL.

Desjarlais points out the concept of thermal mass having energy benefits has been accepted for years and has been a part of the early version of ASHRAE 90.1. “Thermally massive walls have a lower insulation requirement, so there was industry acceptance of the fact that using mass is a way of saving energy,” he says. “But we had a hard time translating that understanding from a wall to a roof. Whether you do that with a concrete block or a bunch of rocks doesn’t really matter. The metric is no different. Roofs or walls.”

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An ERA Study Proves EPDM Easily Lasts More than 30 Years

More and more building owners are seeing the light: Roof systems based on historical in situ performance for more than 30 years are the best roof system choice to benefit the environment. EPDM roof membrane has been utilized as a roof cover for more than 40 years, and there are numerous examples of ballasted roofs greater than 30-years old still performing. New seaming technologies, thicker membrane and enhanced design are creating roof systems with projected 50-year service lives. EPDM roof covers’ physical characteristics have changed little in 30 years, and because potential for 50-year-plus service life is possible, they are a solid choice of design professionals, building owners and school district representatives who truly desire a roof system that benefits the environment.

PHOTO 1: This ballasted 45-mil EPDM roof system has been in service for 32 years.

PHOTO 1: This ballasted 45-mil EPDM roof system has been in service for 32
years.

In 2010, the Washington, D.C.-based EPDM Roofing Association (ERA) was determined to answer the question: “How long can an EPDM roof perform?” Consequently, roof membrane samples from five roof systems with a minimum age of 30 years were obtained for testing of their physical properties. The physical and mechanical properties evaluated (using relevant ASTM standards) were overall thickness, tear resistance, tensile set, tensile strength and elongation, and water absorption. The results were positive, showing that even after 30 years of infield exposure nearly all the physical characteristics of EPDM membrane meet or exceed ASTM minimums. But the question of how long EPDM roofs could last remained. Thus, a second phase of testing was undertaken.

These properties were studied for “as received” and “after heat-conditioning” for up to 1,500 hours at 240 F. Results showing how these membranes performed before and after heat-conditioning are presented with the intent of defining characteristics for long-term service life of roof membranes.

TESTING PHASE ONE

Ethylene-propylene-diene terpolymer (EPDM) has been used in waterproofing and roof applications for more than 45 years in North America. Introduced into the roofing market in the 1960s, EPDM grew, especially after the 1970s oil embargo, to be a roofing membrane choice for new construction and roofing replacement projects. EPDM has achieved long-term in situ performance in part because of its chemical structure, mostly carbon black, which resists ozone and material decomposition, as well as degradation caused by UV light, which is the No. 1 degradation element to roofing materials exposed to the sun (see photo 1). The carbon black also provides reinforcement, yielding improved physical and mechanical properties.

Long-term performance of roof-cover material is dependent upon its resistance to the combined effects of ponding water, UV radiation, ozone, heat and thermal cycling. Geographical location can exacerbate or reduce the impact of climatic factors. In ballasted systems, the ballast acts to provide protection from the UV rays and minimizes the effect of climatic influences.

ERA’s study had three specific goals:

    1. Verify the long-term performance characteristics of EPDM membranes over 30 years. (At the time of the study, the only in situ membranes that were around for 30 years were 45-mil EPDM membranes. Currently 60- and 90-mil are the standard choices. It is assumed that results for the 45-mil material can be prorated for the thicker membrane.)

    2. Scientifically validate the empirical sustainability experiences.

    PHOTO 2: This recently installed, ballasted, 90-mil EPDM roof was designed for a 50-year service life.

    PHOTO 2: This recently installed, ballasted, 90-mil EPDM roof was designed for a 50-year service life.

    3. Create a foundation for specifier-to-owner discussions in regard to long-term service life. Five roofs, four ballasted and one fully adhered, with in situ service lives approaching or over 30 years were identified and samples were taken. All roofs were fully performing without moisture intrusion.

The samples were sent for testing per ASTM D4637 for:

  • Elongation
  • Tensile strength
  • Thickness
  • Factory seam strength (psi)

PHOTOS: HUTCHINSON DESIGN GROUP LTD.

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Long-term Performance of Roof Systems

The April e-newsletter distributed by Roofing contained an online exclusive about sustainability. The author, Brooks Gentleman, an owner of window refurbisher Re-View, Kansas City, Mo., questioned whether we’re talking about the right things when referring to a building as sustainable. He says, “During the past 10 years, there has been a great deal of talk about green buildings and sustainability, but how many of these ‘green’ commercial or residential buildings are designed or constructed to last for centuries? When will the life cycle of the structure and the construction materials themselves become factors in the sustainability criteria? It seems to me that more effort is placed on whether a material is recyclable than whether it can perform over the long haul. It is time that the design community, manufacturers and construction processes begin to consider the life of the building if we are truly going to incorporate sustainability in our industry.” (Read the entire article.)

Gentleman’s commentary is the perfect precursor to this issue, which has a focus on the long-term performance of a roof system. Three “Tech Point” articles explain the life spans of metal, EPDM and asphalt, respectively. The authors—Chuck Howard P.E., a Roofing editorial advisor; Thomas W. Hutchinson, AIA, CSI, FRCI, RRC, RRP, a Roofing editorial advisor; and James R. Kirby, AIA—share roof-cover characteristics that achieve and industry studies that prove long-term performance.

Insulation is a component that will help extend the life of a roof system. In “Cool Roofing”, Kyle Menard, president of Bloom Roofing, Brighton, Mich., shares insight about polyisocyanurate, specifically how it contributes to long-term roof performance and why the roofing industry should educate clients about its importance as part of a roof system.

As architects, building owners and occupants increase their expectations for the environmental performance of the buildings they design, operate and dwell in, building component manufacturers have begun rolling out environmental product declarations, or EPDs. EPDs are related to life-cycle assessments and product category rules, all of which are part of an ongoing effort to provide as much transparency as possible about what goes into the products that go in and on a building. In “Environmental Trends”, Allen Barry writes about the significance of EPDs for the roofing industry.

As a longtime proponent of sustainability, it’s wonderful to see the conversation turning toward the critical issue of durability and long-term performance. Yes, specifying materials with recycled content or from sustainably managed forests is a nice consideration, but if those materials will only last a few years and must be replaced, we’re expending more energy—and money—using them. There’s nothing sustainable about that.

Attach Almost Anything to Corrugated Profiles

CorruBracket 100T from S-5! is designed specifically for corrugated roofing profiles that are common in North America.

CorruBracket 100T from S-5! is designed specifically for corrugated roofing profiles that are common in North America.


CorruBracket 100T from S-5! is designed specifically for corrugated roofing profiles that are common in North America. CorruBracket 100T is affixed to the crest of the corrugation, leaving the drainage plane free of holes to protect against leaks. The bracket can be attached directly to the sheeting, accommodating ancillary attachment anywhere along the corrugation. For heavy-duty applications, the bracket can be fixed into the underlying substrate for additional support without crushing the corrugation. CorruBracket 100T comes with a factory-applied EPDM rubber gasket seal already on the base; the S-5!-patented reservoir conceals the EPDM from UV exposure.

Attach Almost Anything to Select Trapezoidal Roof Profiles

RibBracket from S-5! can be used to mount almost anything onto the most common exposed-fastened, trapezoidal roof profiles marketed in North America.

RibBracket from S-5! can be used to mount almost anything onto the most common exposed-fastened, trapezoidal roof profiles marketed in North America.


RibBracket from S-5! can be used to mount almost anything onto the most common exposed-fastened, trapezoidal roof profiles marketed in North America. The RibBracket comes with a factory-applied EPDM rubber gasket seal already on the base, and the S-5!-patented reservoir conceals the EPDM from UV exposure, preventing drying and cracks. The RibBracket is mounted directly onto the crown of the panel, straddling the profile. No surface preparation is necessary; simply wipe away excess oil and debris, align and apply. RibBracket is economical and facilitates quick and easy installation. The slotted top hole, which accommodates standard M8 nuts and bolts, simplifies alignment and maximizes flexibility in attaching ancillaries.

Install EPDM in Temperatures from 20 to 120 F

Firestone Building Products Co. LLC has launched its Secure Bond Technology, which ensures adhesion coverage across the entire roofing membrane.

Firestone Building Products Co. LLC has launched its Secure Bond Technology, which ensures adhesion coverage across the entire roofing membrane.


Firestone Building Products Co. LLC has launched its Secure Bond Technology, which ensures adhesion coverage across the entire roofing membrane. The company will offer Ultra Ply TPOSA and RubberGard EPDM SA with Secure Bond Technology. RubberGard EPDM SA and UltraPly TPO SA with Secure Bond Technology can be installed in temperatures between 20 and 120 F. The technology has no VOCs and does not emit odor during or after installation. It also is FM tested and approved, meets or exceeds all ASTM requirements and is covered by the Firestone Building Products Red Shield Warranty.

Wind-damaged Roof Systems

Wind damage to roof systems is often catastrophic, placing the building users at a life-safety risk, resulting in interior and furnishing damage and suspension of interior operations, loss of revenues, legal ramifications and great costs to repair. Because of my 30 years of experience in the design of roof systems and forensic investigation, I’m often called upon as an expert witness after wind events. In this article, I’ll review a couple wind-event roof failures, the causes of the failures and how they could have been prevented. I’ll also provide recommendations for failure prevention in the design process for new roof systems, as well as for existing roof systems.

1. The concrete roof deck panels deflected more than 3/4 inch, which the design architect should have accounted for if a thorough field investigation was undertaken.

1. The concrete roof deck panels deflected more than 3/4 inch, which the design architect should have accounted for if a thorough field investigation
was undertaken.

The Perfect Storm

How can it be that when roof systems are to be designed for code-required wind-uplift resistance that so many fail in winds well below the design parameters and/or warranty coverage? The answer could be design-related, material or installation; typically, it involves all three.

Architects and some roof system designers are often not as knowledgeable about roof systems as they should be, have little empirical evidence in how all the components work together as a system, and move beyond their abilities (a violation of their standard of care) when designing roofs where specific detailing is required. In addition, manufacturers are all too often
bringing new products to the marketplace that have not been properly vetted in the field and their long-term performance is truly unknown. Unfortunately, the roofing contractor cannot escape any of this. The lack of proper specification and contract document review; failure to review product data, including installation guidelines for new products; poor project oversight and management; and pressure from general contractors often result in installations that are subpar. The result is a “perfect storm” of design, materials and installation that fail under stress.

Consider the following case studies that I have been involved in as a forensic or “expert” witness when litigation was involved.

Coastal Facility

A large aged warehouse along the eastern seaboard was in need of a new roof system. Because the interior was not conditioned, thermal insulation was not required. The existing roof was an asphalt built-up with aggregate surfacing on high-density fiberboard on precast concrete panels 24-inches wide on a steel structure. The northern portion of the building had overhead doors that were seldom closed. On the interior, an aedicule structure (a building within a building) was constructed approximately 65-feet south of the overhead door, which had a ceiling level 5-feet below the roof deck.

2. The thin, flexible 1/2-inchthick high-density board was found to have little, if any, contact with the full-coverage spray-foam adhesive, making uplift extremely easy.

2. The thin, flexible 1/2-inch-thick high-density board was found to have little, if any, contact with the full-coverage spray-foam adhesive, making uplift extremely easy.

The architect who designed the replacement roof system called for the existing BUR roof to be removed down to the precast concrete roof panels. Then a new 1/2-inch 4- by 8-foot high-density wood fiberboard was set in full-coverage spray polyurethane foam adhesive with a 60-mil EPDM membrane fully adhered to the high-density wood fiberboard.

Additionally, the architectural drawings called for rooftop relief vents to be removed and capped over.

Around June 2008, a Nor’easter (an intense rainstorm), coming in from the east off the ocean, swept into the city. This resulted in the new roof system being lifted off the roof deck. Mode of failure was the fiberboard detaching from the precast concrete roof deck.

Investigation revealed several acts and conditions that contributed to the wind damage.

PHOTOS: Hutchinson Design Group Ltd.

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