New Construction Peer Review Getting the Most out of Your Building Envelope Consultant

I S S U E 4/2013  VOLUME 30  NUMBER 4

Journal of architectural technology published by Hoffmann Architects, Inc., specialists in the rehabilitation of building exteriors. New Construction Peer Review Getting the Most out of Your Building Envelope Consultant

Craig A. Hargrove, AIA and Stephanie L. Dillon, Assoc. AIA

With today’s strict energy conser- specialist can identify ways to reduce vation codes and increasingly com- costs with details that are watertight, plex facade and roof systems, many thermally insulating, and correctly new construction projects involve the constructed; when amplified over the services of a building envelope design entire building, even small improve- professional as part ments can add up to substantial sav- of the project team. ings. Ideally, boosting exterior envelope Making the best use performance can reduce the necessity of that consultant’s for larger mechanical packages and services is impor- mitigate the effect of energy-consum- tant not only to the ing systems, such as lighting. bottom line of the construction project, To realize these benefits, there are but to the energy steps a building owner or design ar- efficiency, code com- chitect can take to get the most value pliance, sustainability, from a building envelope consultant. integrity, and longev- The role of the envelope specialist ity of the building. changes throughout the design and When should a build- construction process, and knowing ing envelope con- when and how he or she should be sultant get involved involved can make a big difference to in a new construc- the project outcome. tion project? What Technical details, such as sealant joint design, make the difference services should he or Material and Assembly Specification between a long-lasting building and one that fails prematurely. she be expected to Because building envelope architects provide? How does and engineers work exclusively with the consultant’s role the outsides of buildings, they tend to differ from that of the architect of amass substantial knowledge of facade record? What, exactly, does a building and roof systems and their proper- envelope consultant do? ties. Therefore, when it comes time to By working with the design team to formulate and apply building envelope establish performance criteria for system criteria – whether budget- the building envelope, the consultant ary, ecological, performance, or design proposes materials and components – the envelope specialist brings key to optimize efficiency across facade background experience to the project and roof assemblies. The envelope team in establishing these parameters

Craig Hargrove, AIA LEED AP, senior vice president of Hoffmann Architects, Inc., oversees the development of design solutions, both for new construction and for the rehabilitation of existing structures. Stephanie Dillon, Assoc. AIA, project manager, provides envelope consultation for building managers and design professionals. JOURNAL

Curtain wall construction at this glass high-rise involved quality control of fabrication, assembly, installation, and field verification, to see that the final product meets design standards for performance and sustainability. and identifying options for suitable envelope design on the size and cost counts. That’s where building envelope envelope systems. of heating and cooling systems. consultants really pay for themselves: Recently, one of our engineers pro- As an example, consider fenestra- by specifying components individually, vided facade design consultation tion design. Energy loss tends to be rather than as a prefabricated system, services for a new residential high-rise greatest at the edges of glazing, where the envelope specialist can handpick in Manhattan. In a city where space is inefficiencies of the frame transfer only those parts that are essential, at a premium, a central consideration thermal load to the glass. By specifying thereby reducing costs on a piece-by- for any developer is how to maximize warm edge spacers – low-conductivity piece basis. interior floor space while meeting materials used in lieu of aluminum to A recent new construction project at design and performance requirements position the panes of insulating glazing a military base in New England pro- for the facade. After evaluating energy units (IGUs) – the envelope consultant vides an excellent example of design code requirements and probable con- can mitigate heat loss across windows collaboration between the architect struction costs, the engineer was able or glazed curtain walls. Even seemingly of record and the envelope specialist. to recommend a facade assembly that minor modifications like this one can With a very tight budget, the project met the relevant energy efficiency re- improve thermal performance enough was nonetheless expected to earn quirements, but which was shallow in to permit downsizing of mechanical LEED certification by using efficient, depth, thereby maximizing apartment equipment, often netting both short- well-designed envelope systems. Our square footage. and long-term savings. building envelope engineer ran ther- With energy code often the prime Green building projects can make mal computer models for a number directive driving design, balancing the most of the building envelope of different roof assemblies, then mechanical package efficiency with consultant by involving him or her provided options to the project team. building envelope thermal resistance in the design phase, to brainstorm In addition, we advised on the integra- has become a central consideration. In exterior wall and roof assemblies and tion of air and vapor barriers, particu- order to achieve the requisite energy to act as a sounding board for design larly at facade/roof intersections. By performance, design teams must offset decisions. Many government projects optimizing the configuration and type an economical mechanical package are now required to obtain certifica- of insulation in the roof assembly, we with strict control of heat transfer tion from Leadership in Energy and were able to assist the design architect across the building exterior. Working Environmental Design (LEED) or simi- in maximizing efficiency while reducing with the mechanical engineer, the lar rating systems. At the same time, construction costs. The project stayed envelope consultant provides options municipal, state, and federal budgets within budget and earned LEED Gold that consider the impact of exterior are stretched thin, and every dollar certification. (continued on page 4)

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The Building Envelope Consultant’s Role

The purpose of an exterior envelope specialist in a new mechanical system efficiency. The envelope consultant construction project is not to supplant the prime ar- can evaluate cost and performance trade-offs and iden- chitect; rather, he or she complements the work of the tify options that fulfill energy code requirements, main- designer by providing focused attention to calculations, tain indoor comfort, and provide long-term value. technical details, codes, standards, and material prop- Act as the problem-solver. Envelope consultants tend erties and assemblies. For new construction projects, to have extensive experience reverse-engineering build- including expansions, additions, and adaptive reuse, the ing exterior failures, which enables them to foresee building envelope consultant’s responsibilities include: potential problems and sidestep them. During con- Maximize efficient use of materials and assemblies. struction, the envelope specialist adds a level of quality Providing options for exterior envelope systems that control, verifying that key details are followed so as to meet performance objectives and budget requirements maintain energy efficiency and weather integrity, and demands in-depth understanding of material properties see that sustainability is not compromised. The building and experience with proprietary systems. The build- envelope consultant responds to unexpected technical ing envelope consultant works with the designer and questions and constructability issues to see that prob- the structural and mechanical engineers to establish lems are resolved cost-effectively and in keeping with performance requirements, then identifies products and the design intent. assemblies that are appropriate to the design and fulfill Make sure the building envelope reflects the designer’s program objectives. Often, the envelope consultant is vision – and still works. Through document review, able to suggest assemblies that reduce costs, maximize mockups, field verification, and testing, the building en- sustainability, improve efficiency, or do all of the above. velope specialist is there to focus on the technicalities of Take care of technical details. Facade enclosure re- installation and real-world performance, to see that the quirements have become so technical that meeting building envelope fulfills intended energy and sustain- complex codes and standards can absorb enough of the ability objectives. The envelope consultant can make architect’s time that it impacts building design. The build- subtle changes to construction details that address ing envelope consultant is responsible for researching technical, logistical, or practical considerations, without and applying the latest building codes and industry stan- compromising the design aesthetic. dards, and then advising the prime architect of the ways The building envelope consultant is best engaged early in which these stipulations impact design decisions. in the design/construction process, before conceptual Keep abreast of changing energy efficiency and green designs are translated into technical documents or be- building requirements. Today’s energy codes can be come tangible reality in the field. Although an envelope tough to pin down, varying not just over time, but also specialist does provide important services during con- from city to city, from building to building, and even struction, bringing the building envelope consultant on from one portion of a building to another. Determining board during the design phase can be instrumental in the insulating value for the building envelope is often a preventing construction delays and change orders that balancing act between facade thermal resistance and can add to project costs.

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(continued from page 2) Codes, Standards, Rules, and to the success of the project. As re- waterproofing system can provide Best Practices flective and vegetated roofs become owners with the reassurance that their increasingly popular, architects are lush green-roof amenity won’t turn With the current trend toward faced with the challenge of selecting, into a leak-ridden liability. increasingly stringent energy codes specifying, and detailing a system that and the push by organizations like meets performance requirements, Constructability Review the American Institute of Architects falls within the available budget, and toward sustainable design and green It’s not uncommon for construction is suited to the building structure, cli- building, the requirements for facade documents to be what one of our en- and roof performance are a moving mate, and location. Well-versed in the gineers calls “light on details.” Because target. Add to that changes to state pros and cons of various waterproof- roof and facade assemblies are often and local building codes and constantly ing systems and roof membranes, proprietary systems, designers tend evolving green building certification the building envelope consultant can to rely on manufacturers’ standard requirements, and the design of even provide recommendations for a roof details. In the field, however, compo- seemingly straightforward envelope el- assembly that meets design objectives. nents don’t always work together as ements becomes anything but simple. For reflective roofs, the envelope spe- smoothly as they do on paper, with intersecting building areas and irregu- To keep up with these tumultuous cialist can assist the owner and archi- lar dimensions that defy boilerplate changes, a design architect would tect in deciding whether, for instance, have to spend a considerable amount a single-ply white sheet system or a drawings. These discrepancies can lead of time on each project researching modified bitumen assembly with re- to change orders and delays as the current codes and scouring industry flective granular cap sheet would bet- project team scrambles to respond to literature for small details like air bar- ter meet stated performance objec- nonstandard or unforeseen conditions. rier terminations or sealant composi- tives. Roofs used as public space raise Pre-construction, the building enve- tion. Fortunately, the building envelope still more questions, such as whether lope consultant reviews drawings and consultant is well positioned to do just recessed terrace lighting might gener- specifications to evaluate or provide that. With building exterior details as ate too much heat too close to insula- details, particularly at intersections, ter- their focal point, envelope consultants tion, or whether transformers can be minations, penetrations, and changes can afford to devote the time and exposed to the elements. from one material to another. The en- attention it takes to stay abreast of Vegetated roofs demand strict atten- velope specialist redlines drawings and current regulations and keep up with tion to waterproofing details, given provides technical information, raising the latest developments in facade and that removing layers of plant matter questions about the finer points of roof systems. and growing medium to search for edge flashing, membrane tie-ins, fas- Cool roof technology is one example a leak is labor-intensive and expen- teners, construction sequencing, and of an area in which building envelope sive. Getting the envelope consul- other information that may be missing consultants are particularly important tant involved in specifying a resilient from or unclear in the design.

Curtain wall installation review: Creating a water-tight intersection is a multi-step process, beginning with application of sealant at the glazing pocket (left), then placement of metal covering over the gap (center), followed by appropriate tooling of sealant at the horizontal weather seal (right).

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Waterproofing installation review: As potential sources of water infiltration, thresholds demand attention to detail. Here, asphalt and roofing felt(left) are applied under the flashing membrane (center) to create a positive lap, then the roofing base membrane is embedded into the asphalt(right) .

Some details might seem to work academic halls. Elegant in its simplicity Field Verification and Testing and innovative in the use of a dynamic on paper, but would be difficult to Even after building exterior compo- construct in practice. While review- facade, the building was featured in nents have been installed, the enve- ing plans for a new addition to a a number of architectural publica- lope consultant remains an important Washington DC business school, our tions and was the recipient of a design part of the project team. Verifying that architects identified roof drain details award. Unfortunately, from nearly the assemblies perform as designed, and that could be simplified, not only day construction was complete, the that they are constructed in accor- shortening construction time, but also building leaked. dance with the contract documents, is improving the longevity and func- Primarily, the flaw lay with the gut- another key role of the building enve- tionality of the roof assembly. Details ter system, the design of which had lope design professional. that might otherwise have been left the unintended effect of channeling In one recent example, a popular to the contractor, such as attachment water toward the building, rather than hotel casino looked to add a high-rise methods for copings and edge protec- away. As a result, the university spent addition to the existing guest accom- tion at changes in roof height, were additional time and money on the modations, to be clad in a unitized addressed in advance, saving time in redesign and reconstruction of the glazed curtain wall assembly. With the field and improving construction entire roof drainage and gutter system. 156 glazed panels per floor and eight outcomes. Involving an envelope consultant to floors of curtain wall cladding, the evaluate facade/roof intersections and Problem Solving building was set to have nearly 1,250 other key integration points might curtain wall units. Asked to review During the contract documents phase, have prevented the failure, by correct- production and installation of the cur- the building envelope consultant’s ing potential trouble spots before the tain wall system, our building envelope role shifts from providing options to project ever went into construction. specialists discovered that fabrication preventing errors. Early in the design Working backward to determine the of some of the panels was not dimen- process, the envelope consultant looks source of a problem—then forward sionally correct, leading to alignment at broad considerations of energy per- again to solve it—is what gives build- problems during installation. formance, code compliance, structural ing envelope design professionals the After sending the panels back to be integrity, sustainability, and cost. Once expertise to avoid those types of deglazed and reconstructed, the own- the project team and the owner agree errors in the first place. After seeing er positioned a full-time representative to move forward with a design, the the same types of detailing mistakes at the manufacturing plant, to improve consultant turns his or her attention over and over again, building envelope organization and quality control. With to construction details. specialists know what to look for, both the additional oversight of the enve- Not long ago, an urban university in contract documents and in the lope specialist, not only did product added a glass-enclosed student center field, to identify and resolve incipient quality improve, but also production in an infill area between two historic problems. volume, rising from 25-30 panels per

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day up to 30-40. The increased output architect of record; they supplement permitted the construction team to the design services that are common catch up with the original project practice for a new construction proj- schedule, erasing the time lost due to ect. Although it is not required that panel defects. an architect provide details for every Once the new panels were installed, single roof termination, for example, the building envelope consultant it is enormously helpful in taking the specified and oversaw air and water guesswork out of installing the roof. infiltration field testing to verify per- The building envelope consultant fills formance of the curtain wall system. in the gaps to help the construction The testing process involves specifying process run as smoothly as possible. the relevant protocols as per industry To make the most of an exterior en- standards—most commonly, those velope consultant, it’s best to involve published by the American Society Fabrication evaluation to verify product him or her early in the design phase, for Testing and Materials (ASTM quality, as part of a third-party review. before construction has begun. That International) or the American Society way, the envelope specialist can raise of Heating, Refrigerating and Air- questions and identify potential prob- on, at which point fixing them would Conditioning Engineers (ASHRAE)— lems while there is still ample time to be much more costly, difficult, and identifying appropriate test locations, correct them. With everything sorted disruptive. establishing performance criteria, and out ahead of time, construction delays observing testing to see that it con- may be less likely, saving money for the forms with the specified test methods. Collaboration property owner and avoiding conflict For units that fail, the envelope con- Perhaps most importantly, involving on the project team. sultant analyzes the test results and a building envelope consultant in a During construction, the envelope the relevant building elements to new construction project frees up the consultant should be available to determine the probable cause and prime architect to focus on design de- review shop drawings and submit- to recommend repairs. The modified velopment, without becoming bogged tals and to observe construction, assembly is then retested to confirm down with the intricacies of water- identifying and responding to incor- that it fulfills performance criteria. proofing detailing, component anchor- age, air barrier specification, or other rect installation, poor workmanship, In our high-rise hotel example, field technicalities. Rather than expend- or unforeseen issues promptly. Once verification and testing uncovered ing the designer’s time on product systems have been installed, the enve- problems that might not otherwise comparisons and code research, the lope specialist can specify and oversee have been noticeable until symptoms client can derive the most value from functional performance testing, such of distress and failure emerged later the prime architect by working with as air and water infiltration tests, to him or her to create a building that correct deficiencies that would oth- satisfies program requirements while erwise result in leaks and premature achieving a desirable and, ideally, inno- deterioration. vative and powerful aesthetic. The Big Picture Green building designers are already responsible for creative solutions to Today’s building systems are complex, the problems of energy consump- and technical requirements are even tion, resource depletion, and carbon more so. To adapt, project teams have emissions, making it all but impossible become more and more specialized, to simultaneously achieve fluency in with separate installers responsible roof wind load code requirements or for each proprietary assembly. Add to best practices for face-sealed glazing that the involvement of independent systems. The services provided by a consultants for mechanical, electrical, An open pipe penetration spotted during building envelope consultant are not a plumbing (MEP), structural engineer- a waterproofing consultation. duplication of those performed by the ing, amenities, lighting, furnishing, (continued on page 8)

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New Construction Consultation Smithsonian Institution, National and Peer Review Museum of the American Indian Washington, District of Columbia As building enclosure experts, Roofing and Waterproofing Consultation Hoffmann Architects’ design professionals not only diagnose and resolve University of Virginia distress in existing buildings; we also Special Collections Library provide consultation and review Charlottesville, Virginia services for new construction. With Waterproofing Design Consultation focused attention to building enve- Yale-New Haven Hospital lope performance, we develop design Clinical Laboratory, 55 Park Street details, review drawings and specifica- New Haven, Connecticut tions, evaluate weather integrity and Building Envelope Consultation energy performance, and provide The Cleveland Clinic options for code-compliant envelope InterContinental Hotel assemblies. Cleveland, Ohio Recent new construction consultation Waterproofing Design Consultation projects include: The Jefferson Library University of Connecticut Health Charlottesville, Virginia Center, Ambulatory Care Center Waterproofing Consultation and The Larstrand at 2182 Broadway in New Farmington, Connecticut Document Review York, New York. Building Envelope Consultation Consultation and Construction Review and Peer Review. Yale University Seneca Allegany Casino & Hotel Loria Center for the History of Art Office Building, 2021 L Street NW Salamanca, New York New Haven, Connecticut Washington, District of Columbia Curtain Wall Design and Building Envelope Consultation Waterproofing Design Review Installation Review and Peer Review Reston Bible Church 2230 Broadway Loudoun County, Virginia New York, New York Third Party Peer Review Building Envelope Consultation Connecticut Army National Guard and Peer Review Regional Training Institute Middlesex County Courthouse Niantic, Connecticut Saluda, Virginia Building Envelope Consultation Waterproofing Design and Park Slope Condominiums Contract Document Review Brooklyn, New York East Rock Magnet School Building Envelope Consultation American University Kogod School of Business in New Haven, Connecticut Sheraton Tarrytown Hotel Washington, District of Columbia. Peer Review Design Building Envelope Design Tarrytown, New York Consultation for New Addition. Consultation Building Envelope Consultation

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JOURNAL is a publication of Hoffmann Architects, Inc., specialists in the rehabilitation of building exteriors. The firm’s work focuses on existing structures, diagnosing and resolving problems within roofs, facades, windows, waterproofing materials, structural systems, plazas/terraces, parking garages, and historic and landmark structures. We also provide consulting services for new building construction, as well as litigation and claim support.

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(continued from page 6) 2321 Whitney Avenue Hamden, CT 06518 sustainable design, renewable energy, True, the value in an exterior envelope 203-239-6660 urban planning, building codes, acces- specialist may be found in the details, sibility, etc., and it seems as though one but it also lies in bringing together the 1040 Avenue of the Americas, Ste. 14C more consultant is the very last thing disparate systems that comprise the New York, NY 10018 a project team needs. But the role of 212-789-9915 building’s exterior shell. The most criti- the building envelope consultant is not 2611 Jefferson Davis Highway, Ste. 200 to look at one system in isolation; it’s cal role a building envelope consultant performs for any project, whether new Arlington, VA 22202 to make sure that the exterior enve- 703-253-9800 lope—in consort with the mechanical construction or rehabilitation, is to and energy packages—works together make sure the building envelope per- www.hoffarch.com as a whole. forms as intended, and performs well. Editor: Alison Hoffmann Production: Cari Tate

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