Saddle Flashing Detailing, Mock-Ups, and Construction Sequencing Michael Nagle, RA, NCARB Wiss, Janney, Elstner Associates | Cleveland, OH mnagle@wje.com IIBEC International Convention & Trade Show | SeptembeBEr 15-20, 2021 N Nagle | 117 Michael Nagle, RA, NCARB Wiss, Janney, Elstner Associates | Cleveland, OH Michael R. Nagle, RA, NCARB, is a building enclosure consultant with Wiss, Janney, Elstner Associates Inc. (WJE), specializing in facade, windows, and roofing problems in existing, historic, and new buildings. Since joining WJE in 2004, he has provided consulting services for numerous projects involving water and air infiltration, condensation, and distress conditions in a variety of building enclosure systems, including brick masonry, stone, terra cotta, windows, curtain wall, metal wall panels, exterior insulation and finish systems, stucco, sealants, roofing, and waterproofing. He is an active member in the Cleveland chapter of the Building Enclosure Council and a member of Committee on Technical Committee Operations, Subcommittee on Regulations. 118 | Nagle II BEC International Convention & Trade Show | September 15-20, 2021 ABSTRACT SPEAKER Moisture-related damage to building components resulting from water infiltration is a common occurrence at parapet terminations at high-rising walls due to discontinuities in the weather-resistive control layer at this critical interface condition. A combination of a lack of detailing and the lack, or improper installation, of the necessary materials to achieve a continuous weather-resistive control layer at parapet terminations against high-rising walls contributes to this issue. After reviewing industry-recognized saddle flashing details, which are limited for applications other than exterior insulation and finish systems and stucco, this paper presents multistep isometric details developed by the author to show the integration of the air-, vapor-, and weather-resistive barriers, roofing membrane, throughwall flashing, and sheet metal flashing for inclusion in one or more industry-recognized standard detail manuals. Additionally, the paper describes the author’s recent collaboration with the International Masonry Institute to construct saddle flashing mock-up walls with the assistance of a manufacturer and contractors. These mock-ups will be used as an educational tool to help design professionals, construction managers, building enclosure consultants, manufacturers, contractors, and industry organizations succeed in the design and installation of saddle flashing. Moisture-related damage is common at parapet terminations of lower building portions against higher building walls (high-rising walls) that lack proper integration of the air and moisture control layers. In the author’s experience, saddle flashing conditions are seldom detailed or specified within the design documents, the condition is often not installed correctly, and failure to properly address this condition during the design and construction phases can lead to water and air leakage issues in buildings. Currently, there are very few industryrecognized saddle flashing details available to provide guidance on the integration of the air and moisture control layers. Among the limited resources for design professionals and contractors on this topic are the current Exterior Insulation and Finish Systems (EIFS) Industry Members Association (EIMA) Guide to EIFS with Drainage Detailing,1 EIFS and stucco manufacturers’ standard details, and a series of parapet-to-wall details in Chapter 15: “Details and Practice” of ASTM International’s Moisture Control in Buildings: The Key Factor in Mold Prevention, second edition.2 This paper provides needed guidance to (a) design professionals and building enclosure consultants for the development of projectspecific details for incorporation into their projects, (b) manufacturers for incorporation into their standard details, and (c) recognized construction-industry organizations to develop detail standards for reference by industry professionals and contractors. To address the limitations in available industry-recognized details depicting options to achieve a continuous water-resistive control layer at parapet terminations against high-rising walls, the author has developed multistep isometric details showing the integration of the air-, vapor-, and weather-resistive barriers, roofing membrane, through-wall flashing, and sheet metal flashing for further development and inclusion in one or more detail manuals published by, for example, the National Roofing Contractors Association (NRCA) or the International Masonry Institute (IMI). With the assistance of a manufacturer and multiple contractors, the author collaborated with the IMI to construct saddle flashing mock-up walls representing a series of installation steps using the necessary flashing materials to achieve a continuous air and moisture control layer at a parapet termination against a high-rising wall. The mock-up walls will be used as an educational tool for design professionals, construction managers, building enclosure consultants, manufacturers, contractors, and industry organizations to succeed in the design and installation of saddle flashings. THE PROBLEM Interestingly, architects and designers enjoy developing complex, award-winning building designs that are often conveyed using three-dimensional modeling software, yet three-dimensional details (i.e., isometric and axonometric details) of critical flashing transitions are seldom incorporated into the design drawings. Why is it that firms often receive design awards for their most beautiful, inspiring, and eye-catching designs, but awards are seldom given for building enclosures that have demonstrated outstanding performance after being in service for several years? Most award-winning building designs include numerous unique and complex interface conditions. Far too often, these unique and complex interface conditions lack a sufficient level of detail and have the propensity to lead to a host of latent building enclosure problems. These problems are disruptive and can lead to change orders, construction delays, water-related damage, and construction claims. While design professionals understand that most air and water intrusion problems occur at interface conditions of differing building enclosure components, these complex conditions are not often detailed and are instead left for the contractor or contractors to resolve during construction. This situation could possibly be a result of the lack of understanding of critical interface conditions, limited available industry-recognized details, complex building designs with limited design fees, short design and construction schedules, the shifting of design responsibilities toward the contractor, or an overreliance on the contractor’s knowledge and level of skill. One condition that warrants more attention by design professionals, construction managers, building enclosure consultants, manufacturers, contractors, and recognized construction industry organizations is the integration of the terminal ends of parapets and roof edges into the adjacent wall construction of the upper floors and penthouses. The flashing configuration at this interface condition is referred to as saddle flashing and will be discussed in detail within this paper. DESIGN FUNDAMENTALS Building enclosures provide a separation between the interior and exterior environments, which allows the interior environment to be controlled and conditioned. Ideally, building enclosures provide continuous layers that control rainwater penetration, air leakage, vapor diffusion, and thermal conduction. Frequently, one or more of these boundaries II BEC International Convention & Trade Show | September 15-20, 2021 N agle | 119 Saddle Flashing Detailing, Mock-Ups, and Construction Sequencing Why is it that firms often receive design awards for their most beautiful, inspiring, and eye-catching designs, but awards are seldom given for building enclosures that have demonstrated outstanding performance after being in service for several years? can be achieved with a single material that is integrated with other building cladding components and assemblies to form a continuous barrier between the interior and exterior space. A continuous building air and moisture barrier can be achieved when the opaque wall air/moisture control layer is integrated with fenestration systems around rough openings in the wall, the roofing assembly at the top of the walls, below-grade waterproofing elements, and barrier cladding elements, with flashings and sealant. Discontinuities or holes in these boundaries, either within a material itself or at the interface with an adjacent material or cladding assembly, can result in air leakage and water penetration pathways that bridge interior and exterior conditions. A general understanding of the differences in the principal exterior wall types and the four primary building enclosure control layers (air, moisture, vapor, and thermal) is essential for the proper detailing and construction of saddle flashings. Preventing the migration of water through an exterior wall system to the interior spaces can be achieved by one of three fundamental concepts: mass walls, drainage walls, and barrier walls. Mass walls, which are generally associated with masonry construction, resist water infiltration to the interior by relying on the bulk of the exterior wall system absorbing the water that penetrates the exterior surface of the masonry. To be effective, mass walls typically require multiple wythes of masonry. If the amount of water introduced into the mass wall is greater than the wall’s absorptive capacity, water infiltration to the interior may occur. Drainage walls are designed to resist the migration of water to the interior by establishing a continuous clear cavity or air space between the inboard surface of the exterior cladding and the backup system. Drainage walls typically consist of an exterior cladding material, air space, and backup framing with a water management system consisting of a weather-resistive barrier, flashings, and backup wall. There is a wide variety of types of weather-resistive barriers, many of which can also function as air and vapor barriers when they are detailed and installed in a manner to provide air and vapor control within a given exterior wall assembly. However, the term “weather-resistive air barrier” will be used for the purposes of this paper when referring to the air and moisture control layers. The presence of a clear air space should prevent water from migrating through the exterior cladding in a drainage wall from bridging to the backup wall. At this point, the water’s only path of travel is down the inboard surface of the exterior cladding, where it can be managed by a system of flashings and weeps. If high winds accompany rain, water that reaches the air cavity may be blown to the backup wall in exterior walls with certain cladding systems (e.g., rainscreen cladding). The design should account for this when the building is in a high-wind area. Barrier walls resist water infiltration to the interior by shedding water at the outboard surface of the exterior cladding. Barrier walls do not incorporate water management systems, such as air and water barriers and flashings, within the walls to redirect incidental moisture that migrates into the wall back to the exterior. Barrier walls are heavily reliant on the watertight integrity of the exterior cladding system, seals, and coatings. As noted previously, the four primary building enclosure control layers are the water, air, vapor, and thermal control layers. Best practices include designing and installing building enclosure control layers in a manner that maintains continuity of each layer around the entire building enclosure. Of the four primary control layers, the continuity of the air and moisture control layers at saddle flashing conditions is generally most critical due to the potential for air and water leakage to the building interior. The approach to detailing and installation of saddle flashing, and the integration of the air and moisture control layers, varies depending on the selected enclosure systems, the building geometry at the parapet-to-wall condition, and the arrangement of the building materials at the interface condition. For mass walls and barrier walls, the detailing of saddle flashings differs considerably from drainage 120 | Nagle IIiiBEC International Convention & Trade Show | September 15-20, 2021 Figure 1. Example of copper saddle flashing (dashed outline) installed on a building constructed in 1913. walls, which incorporate weather-resistive air barriers, through-wall flashings, and weeps. EARLY SADDLE FLASHING EXAMPLES Surprisingly, saddle flashing is not a novel idea. The 1954 edition of the Architectural Graphics Standards,3 includes isometric, plan, and section details at a parapet-to-wall condition between a low building and a high building. These saddle flashing details illustrate a copper coping, head wall flashing, counterflashing, and building expansion joint at a low parapet to high-rising wall condition between two buildings. Similar detailing is included in the same standard for a head wall condition at the terminal end of a copper built-in gutter that abuts a higher building wall. Other examples of saddle flashing that are now over 20 years old include details in a 1993 publication of the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) Architectural Sheet Metal Manual, fifth edition,4 and a 1997 publication of the Stucco Resource Guide, third edition, by the Northwest Wall and Ceiling Bureau.5 Occasionally, examples of saddle flashing can be found on older buildings, such as a 16-story building constructed in 1913 (Fig. 1). The saddle flashing occurs at the end of a copper coping of a lower roof that meets a wall of a higher building portion that is clad with copper siding. CONTEMPORARY SADDLE FLASHING RESOURCES A few contemporary examples of saddle flashing details are available, although industry-recognized saddle flashing details are generally limited to EIFS and stucco applications and tend to exclude other exterior cladding systems (e.g., brick masonry, metal wall panel). Three-dimensional saddle flashing details with exploded views for EIFS applications are included in the EIMA Guide to EIFS with Drainage Detailing (Fig. 2). Similar saddle flashing details for EIFS and stucco applications can be obtained from EIFS and stucco manufacturers’ standard details. The EIFS manufacturer standard details include three-dimensional, step-by-step saddle flashing details. One EIFS manufacturer includes a saddle flashing detail that incorporates three sheet metal components: a saddle that straddles the parapet and two side flanges at the parapet-to-wall interface condition, all of which are detailed in a shingled manner that sheds water to the exterior. Another EIFS manufacturer includes a one-piece saddle with an integral upturned leg with continuous side flanges. SMACNA’s Architectural Sheet Metal Manual,6 seventh edition, includes a saddle flashing detail in figure 3-8D. The detail, which is also available in the fifth and sixth editions and has not changed substantially since the fifth edition, illustrates a sheet metal saddle that straddles the parapet wall and extends through the brick veneer with a sheet metal flange within the drainage cavity. Because details in SMACNA’s Architectural Sheet Metal Manual are intended to provide guidance for the design and installation of custom-fabricated sheet metal, the details do not include the integration of the air and moisture control layers. Chapter 15: “Details and Practice” of ASTM International’s Moisture Control in Buildings: The Key Factor in Mold Prevention, second edition,2 presents a series of step-by-step details (Details 5A through 5I) at a parapet to high-rising wall junction in a building with masonry veneer with an air cavity. These details show the progression of the installation of the weather-resistive air barrier, roofing membrane, masonry veneer, and shelf angle, and insulation and the integration of the control layers at the intersecting walls. The details are developed in a manner such that the masonry on the high-rising wall extends vertically past the parapet and with the portion of masonry located above the lower roof held above the coping and roofing with a steel shelf angle. A masonry control joint is detailed at the junction of the parapet to high-rising masonry veneer walls separating the multistory masonry veneer from the masonry veneer above the lower roof. At the lower roof, the masonry veneer and shelf angle project outboard and above the sheet metal coping. The series of details is successful in showing the integration and continuity of the weather-resistive air barrier and roofing membrane. However, the series of details does not incorporate a sheet metal saddle flashing at the terminal end of the coping. Because the details do not incorporate a sheet metal saddle flashing, additional design and consideration are needed to detail the end of the coping at the interface with the masonry veneer and shelf angle to prevent rainwater and melting snow from migrating into the air cavity of the masonry veneer wall. Based on the author’s research, resources from recognized construction industry Figure 2. Saddle flashing details excerpt from the EIMA Guide to EIFS with Drainage Detailing.1 Detail is included courtesy of the EIFS Industry Members Association. II ii B E C International Convention & Trade Show | September 15-20, 2021 N Nagle | 121 organizations—including The NRCA Roofing Manual: Membrane Roof Systems,7 The Brick Industry Association (BIA) Technical Notes,8 IMI Masonry Detailing Series,9 and Copper and Common Sense, 8th edition, by Revere Copper Products Inc.10—did not incorporate saddle flashing details within their design manuals at the time that this paper was written. INVESTIGATIVE FINDINGS The author’s first encounter with moisture-related distress to building components resulting from the lack of saddle flashing occurred during a water infiltration investigation of an EIFS-clad residence in 2005. The two-story residence has a one-story terrace level with parapets and copings that abut the second-floor exterior wall. No drawings were made available for review. A barrier EIFS cladding had been installed on both sides of the parapet and the adjacent second-floor wall. Removal of the parapet coping revealed that the wood blocking at the top of the parapet was covered with a self-adhered membrane underlayment. The EIFS cladding on the second floor extended down to the top of the wood blocking. The interface condition between the terminal edge of the self-adhered membrane underlayment and the adjacent EIFS was sealed with a fillet bead of sealant. The self-adhered membrane underlayment that covered the wood blocking at the parapet did not extend up behind the EIFS of the second-floor wall. Moisture levels in the wood blocking were high, and the wood blocking was significantly deteriorated at the parapet-to-wall interface (Fig. 3). In 2009, the author investigated water infiltration at an academic building that was designed by a world-renowned architect. The building enclosure consisted of barrier EIFS, aluminum-framed curtainwalls, and single-ply roofing. The building configuration incorporated many roof levels at varying elevations and stepped parapet conditions. One of the many sources of water infiltration into the building occurred at the terminal ends of the parapets that interface with adjacent higher walls and at stepped parapet conditions. The detailing of the sheet metal coping at the parapet-to-wall interface condition was inconsistently installed, with most coping ends extending into EIFS cladding of the higher wall and sealed at the perimeter of the coping-to-EIFS interface with sealant. The architec122 | Nagle IIiiBEC International Convention & Trade Show | September 15-20, 2021 Figure 3. Deteriorated and wet wood blocking at a parapet-to-wall condition. Figure 4. Coping with the exterior insulation and finish systems lapped over the upturned leg of the coping. Side flanges (dashed outline) were omitted. Figure 5. Parapet-to-wall condition with no integration of the single-ply roofing membrane with the exterior insulation and finish systems. tural detail called for concealed metal flashing with an integral upturned leg installed below the coping at stepped parapet conditions and parapet-to-wall conditions. The architectural details did not specify side flanges or other means to redirect water to the exterior. At some areas, the EIFS cladding lapped over the upturned leg of the coping (Fig. 4). No concealed sheet metal flashing was installed. A single-ply roofing membrane was extended up and over the parapet and lapped down over the wood blocking in general accordance with the design drawings. No attempts were made by the contractor to extend the single-ply roofing up onto the higher wall (Fig. 5). Diagnostic testing replicated water infiltration into the building interior two stories below the coping condition. The wood blocking and exterior sheathing were water damaged. In 2013, the author investigated problems associated with a newly completed EIFS drainage system at a large commercial building. During the investigation, several parapet- to-high rising wall conditions were found to be inconsistent with the EIFS manufacturer’s standard details. No water infiltration had been reported, but a few inspection openings were made to confirm whether the conditions were constructed in general accordance with the EIFS manufacturer’s recommendations. The inspection openings revealed that some attempts were made to integrate the air/moisture barrier and the roofing membrane to provide water management in a manner that promotes drainage of incidental moisture to the exterior (Fig. 6). Proper design and installation of saddle flashing requires careful consideration to properly integrate the air and moisture control layers while accounting for construction sequencing and coordination of various construction trades. Saddle flashing conditions can be made more challenging when introducing multiple cladding systems, fenestration systems, or building expansion joints (Fig. 7 and 8). CONTRACT DOCUMENTS Detailing of parapet and coping conditions in architectural drawings is typically limited to two-dimensional wall sections and enlarged details. Seldom do architectural drawings include details for the terminal ends of parapets to the adjacent walls of low-to-high building conditions. However, on occasion, the author has seen three-dimensional details incorporated II BEC International Convention & Trade Show | September 15-20, 2021 N agle | 123 Figure 6. Some integration of the roofing membrane with the air/moisture barrier behind the exterior insulation and finish systems drainage system. However, no transition flashing was provided to integrate the roofing membrane termination to the air and moisture control layer (arrow). Figure 7. End of parapet-to-wall at a building corner with brick masonry, metal wall panels, roofing, and a roof-to-wall expansion joint. Figure 8. End of parapet-to-wall interface condition with curtainwall, counterflashing, roofing, and building expansion joint. within architectural drawing sets for complex interface details, with some of the details showing multiple steps. Providing multistep, three-dimensional details of critical interface conditions in architectural drawing sets helps achieve the desired goals for air and water penetration resistance, overall rainwater management, durability, and future maintenance requirements. Three-dimensional details are strongly recommended for complex interface conditions, such as fenestration head-to-jamb and jamb-to-sill conditions, kick-out (i.e., diverter) flashing at sloped roof-to-wall conditions, and saddle flashing conditions. The introduction of comprehensive multistep, three-dimensional details by recognized construction industry organizations and manufacturers will help provide design professionals with useful resources to develop and incorporate project-specific details into their building designs and assist the construction trades with the integration of their materials at saddle flashing conditions. Architectural technical specifications for sheet metal flashing and trim often reference standards in SMACNA’s Architectural Sheet Metal Manual,6 without specifically mentioning saddle flashing details. It should be noted that this manual includes many details and often has multiple ways of detailing a given condition. Although SMACNA includes a single detail for saddle flashing in the Architectural Sheet Metal Manual, the detail does not show the integration of the weather-resistive air barrier, membrane flashings, and through-wall flashings with the saddle flashing. If architectural drawings do not include project-specific saddle flashing details and the technical specifications do not explicitly address all the requirements for saddle flashing, including integration with the weather-resistive air barrier, the design intent may not be fully understood, and the installation of this critical interface condition may not be installed effectively to mitigate the risk of water infiltration. In the master specifications made available by multiple industry organizations for use by design professionals, the sections for sheet metal flashing and trim and roof specialties generally include provisions pertaining to interface conditions with adjoining work. However, these sections do not specifically address saddle flashing. It is strongly recommended that parts 1 through 3 of project technical specifications be developed to include the following project-specific provisions for saddle flashing: • Part 1: General — Shop drawings. The shop drawing section should be expanded to require project-specific details and specifically list required interface details for the design professionals review, including saddle flashing and other critical interface conditions. — Mock-ups. The mock-ups section should be expanded to include saddle flashing and other applicable interface conditions, including the detailing of the roofing, cladding, flashings, weather-resistive air barrier, thermal insulation, and weeps at the saddle flashing. The saddle flashing mock-up may be incorporated into the building as an in-place mock-up or incorporated into a larger field mock-up of the exterior walls, windows, and other building enclosure components (Fig. 9). • Part 2: Products. This section should be expanded to include project-specific requirements for saddle flashing, including the sheet metal material type, gauge, finish, and fastener requirements. • Part 3: Execution — Fabrication. This section should be expanded to include requirements for saddle flashing, including prefabricated saddles with fully soldered seams, and upturned back legs that integrate with the side flanges. — Installation of roof flashings. Project-specific installation steps should be included within this section for the integration of the coping, saddle flashing, weather-resistive air barrier, through-wall flashing, and roof counterflashings. — Performance testing. Performance testing requirements for saddle flashing conditions, including water infiltration testing methods, test durations, number of tests, and pass/fail criteria, should be included in this section. SADDLE FLASHING DETAIL DEVELOPMENT A series of details were prepared by the author for use as a reference guide for design professionals, construction manager, build124 | Nagle IIiiBEC International Convention & Trade Show | September 15-20, 2021 Figure 9. Example of construction mock-up incorporating a saddle flashing condition at the parapet–to–high-rising wall condition. Photograph provided courtesy of M+A Architects of Columbus, Ohio. ing enclosure consultants, manufacturers, contractors, and industry organizations to develop and properly integrate the sheet metal saddle flashing components, weather-resistive air barrier, roofing membrane, through-wall flashing, and weeps (Fig. 10–12). Three isometric details were developed to depict the installation steps of the saddle flashing condition; these details are to be used along with two adjoining roof-to-wall conditions that are illustrated in The NRCA Roofing Manual: Membrane Roof Systems.7 Details TP-1 and TP-7 from The NRCA Roofing Manual: Membrane Roof Systems, 2019 edition, for use with thermoplastic polyolefin roofing systems were selected to establish the configuration of the parapet condition and the roof-to-wall condition with counterflashing. The detailing of the saddle flashing condition may be made more or less challenging, depending on the position of the roof counterflashing relative to the coping. Where feasible, the number of cladding systems and the arrangement of the cladding and roofing system components should be considered during design to minimize the number of complex construction details. It should be noted that NRCA’s details TP-1 and TP-7 do not incorporate exterior wall insulation and weather-resistive air barriers because these conditions often vary for a given building design, climate zone, and other project objectives. Therefore, to maintain consistency with other NRCA details, the saddle flashing details described in this paper were developed without thermal insulation at both wall conditions and with only the weather-resistive air barrier at the high-rising wall. These saddle flashing details will need to be further developed and adapted for project-specific conditions, and any use of the details remains the sole responsibility of the design professional and construction team. The isometric details were shared with NRCA and the IMI for review and possible incorporation into their design manuals. When detailing saddle flashing in drainage wall applications, the designer must also consider how to maintain continuity of the air and moisture control layers when compared to mass and barrier-type walls. A minimum of three details (as discussed later) must be incorporated into the design drawings to more accurately convey the design intent. Incorporation of additional steps may be beneficial to provide a more comprehensive understanding of the design approach. These details are often easier to design and install for new construction projects than for existing buildings where accessibility and an overall understanding of as-built conditions are limited. For step 1 of the saddle flashing installation sequence (Fig. 10), the exterior cladding (brick masonry) is installed up to the point where the through-wall flashing is installed. This involves coordination between the exterior cladding trade (i.e., mason), roofing contractor, and the contractor responsible for the through-wall flashing (this is often the masonry subcontractor but, in some cases, may be a weather-resistive air barrier installer). The roofing membrane and roof flashing are extended up and over the parapet. On the outboard side of the parapet, the roofing membrane is lapped down over the blocking and sealed to the weather-resistive air barrier (not shown in the detail in Fig. 10) to maintain II ii B E C International Convention & Trade Show | September 15-20, 2021 N Nagle | 125 Figure 10. Saddle flashing detail (step 1). Figure 11. Saddle flashing detail (step 2). Figure 12. Saddle flashing detail (step 3). air/water barrier continuity. At the terminal end of the parapet, the roofing membrane is lapped up, secured, and sealed to the high-rising wall to manage and redirect water that migrates beneath the coping to the top of the roofing membrane, and ultimately to drain to the exterior. After the roofing membrane is secured and sealed to the high-rising wall, a prefabricated, one-piece (i.e., fully sealed or soldered) sheet metal saddle is installed at the parapet-to-higher wall interface. Step 2 of the installation sequence (Fig. 11) involves installation of the coping, sheet metal through-wall flashing, two-piece counterflashing, membrane through-wall flashing, and weeps. This step involves multiple trades. At this point in the installation sequence, the trade responsible for the flashing installation needs to be available to install the flashing components. Watertight continuity of the stepped sheet metal through-wall flashing needs to be maintained, and fully sealed or soldered end dams must be incorporated at the terminal ends of the flashing. Placement of weeps should meet or exceed the minimum design standards as recommended by the BIA or IMI. An additional weep should be considered at stepped through-wall flashing conditions to manage additional moisture that may collect on the through-wall flashing assembly by lateral migration of moisture within the masonry drainage cavity. Step 3 completes the saddle flashing installation sequence (Fig. 12) by lapping the weather-resistive barrier over the through-wall flashing and the installation of the brick masonry. With the sheet metal and membrane flashings installed, the area is ready for the installation of the weather-resistive air barrier. If sheet-applied weather-resistive air barriers are used, they may be installed earlier in the sequence, and the weather-resistive air barrier in the area around the saddle flashing can be temporarily lifted and taped out of the way to allow for the installation of the through-wall flashing. The bottom termination of the weather-resistive air 126 | Nagle IIiiBEC International Convention & Trade Show | September 15-20, 2021 Figure 13. An early stage of the saddle flashing mock-up before the installation of the sheet metal through-wall flashing, saddle flashing, and coping. Figure 14. An intermediate stage of the saddle flashing mock-up with the sheet metal saddle, sheet metal drip edge, two-piece counterflashing receiver, and end dam underway. barrier should be lapped, taped, and sealed to the through-wall flashing in accordance with the manufacturer’s installation instructions to maintain continuity of the air control layer. MOCK-UP DEVELOPMENT The IMI and the Bricklayers and Allied Craftworkers (BAC) of Local 5 Ohio constructed three mock-ups to demonstrate a parapet-to-wall interface condition and further evaluate and explore the feasibility of installing the saddle flashing detail with the masonry, roofing, weather-resistive air barrier, flashings, and weeps (Fig. 13–15). The mock-ups were based on details developed by the author and included in this paper, but they were adapted to include concrete masonry unit backup, a weather-resistive air barrier, rigid board cavity insulation, and a masonry control joint. The saddle flashing mock-ups were built in collaboration with Wiss, Janney, Elstner, Associates, Inc. (WJE), IMI, BAC, Tremco Sealants & Waterproofing (Tremco), and Warren Roofing & Insulating (Warren). Materials were provided courtesy of IMI, Tremco, and Warren. The masonry apprentices at the training center were also excited to learn about the saddle flashing mock-ups. An online video11 prepared by Tremco highlights the construction of the mock-up and the collaborative effort of the team. NEXT STEPS IMI and WJE plan to use the constructed mock-ups as an educational tool for design professionals, construction managers, building enclosure consultants, manufacturers, contractors, and industry organizations to enhance the construction industry’s understanding of saddle flashing conditions. The possibility of conducting water infiltration performance testing on the mock-ups has been considered. The IMI and WJE will develop a set of saddle flashing details to incorporate into IMI’s online Masonry Detailing Series. CONCLUSION Lessons learned from the development of the details and construction of the mock-ups include the following: • Except for EIFS and stucco applications, there are limited saddle flashing details available from recognized construction industry organizations for reference by design professionals and contractors. However, saddle flashing details can be found in design standards dating back to 1954. • Trade organizations and manufacturers are encouraged to develop and provide design professionals with example saddle flashing details incorporating the air and moisture control layers. • The saddle flashing detail in SMACNA’s Architectural Sheet Metal Manual is intended to provide guidance for the design and installation of custom-fabricated sheet metal saddle flashing; it does not include the integration of the saddle flashing with the air and moisture control layers. • The series of details in Chapter 15: “Details and Practice” of ASTM International’s Moisture Control in Buildings, second edition, may be useful in developing project-specific details that incorporate the weatherresistive air barrier and roofing at parapet to high-rising wall conditions. These details must be further developed for project-specific conditions, including incorporation of sheet metal saddle flashings at the intersecting walls to prevent rainwater and melting snow from migrating into the masonry air cavity. • Three-dimensional models are strongly recommended to develop the saddle flashing design and convey the design intent in a clear and concise manner to contractors. • Depending on the overall complexity of a given condition, more than three details may be necessary to more clearly convey each step of the installation sequence and the design intent to contractors. • Expansion of applicable technical specifications is strongly recommended to include project-specific shop drawings, integration of the air and moisture control layers, installation requirements, and mock-ups and performance testing for saddle flashing conditions. • The design objectives associated with the air and moisture control layers and maintaining their continuity at the saddle flashing condition should be discussed and clearly understood by all parties, including the design professional, construction manager/general contractor, trade contractors, and manufacturer representatives for each system. • Onsite mock-ups are most effective when all parties, including the design professional, contractors, and manu- II BEC International Convention & Trade Show | September 15-20, 2021 N agle | 127 Figure 15. A later stage of the saddle flashing mock-up with all sheet metal components installed and self-adhered flashing membrane in place. The next steps included laying the brick masonry with weeps and installation of a masonry control joint (not shown). facturer representatives, collaborate in the review, critique, and improvement of the detail condition. • Construction sequencing and constructability should be carefully reviewed during the design and construction of the mock-up to confirm and adjust the saddle flashing detail so that it is constructible, sequenced properly, and performs as expected. • Performance testing, including water infiltration testing, is useful in evaluating the performance of, and refining, the saddle flashing detail. • Preconstruction meetings should include discussions pertaining to requirements of the saddle flashing conditions and integration with the air and moisture control layers. For further reading, the author has written a blog in Build Meets World titled “An Architect’s Guide to Parapet-to-Wall Detailing” in October 2020 and co-authored an article in the Construction Specifier Failures column, titled “It is time to saddle up!” in the December 2020 issue.12–13 ACKNOWLEDGMENTS Thank you to the hard-working personnel from IMI, BAC, Tremco, and Warren for their support and for furnishing the materials and building the mock-ups. A special thanks to Tom Elliott, director of Industry Development and Technical Services at IMI, for coordinating the mock-up effort, providing use of the IMI training center, and sharing his passion to improve the construction industry. REFERENCES 1. EIFS Industry Members Association (EIMA). EIMA Guide to EIFS Drainage Detailing. Falls Church, VA: EIFS, 2016. 2. ASTM International. Moisture Control in Buildings: The Key Factor in Mold Prevention, 2nd ed. West Conshohocken, PA: ASTM International, 2009. 3. Ramsey, C. G. and H. R. Sleeper. Architectural Graphics Standards for Architects, Engineers, Decorators, Builders and Draftsmen, 4th ed. New York: Wiley, 1954. 4. Sheet Metal & Air Conditioning Contractors’ National Association (SMACNA). Architectural Sheet Metal Manual, 5th ed. Chantilly, VA: SMACNA, 1993. 5. Northwest Wall and Ceiling Bureau. Stucco Resource Guide, 3rd ed. Woodinville, WA: Northwest Wall and Ceiling Bureau, 1997. 6. SMACNA. Architectural Sheet Metal Manual, 7th ed., Chantilly, VA: SMACNA, 2012. 7. National Roofing Contractors Association (NRCA). The NCRA Roofing Manual: Membrane Roof Systems. Rosemont, IL: NCRA, 2019. 8. Brick Industry Association. Technical Notes on Brick Construction. Accessed March 22, 2021. https://www.gobrick.com/read-research/technical-notes. 9. International Masonry Institute. “Masonry Detailing Series.” Accessed March 22, 2021. https://www.imiweb.org/masonry-detailing-series-3. 10. Revere Copper Products. Copper and Common Sense, 8th ed. Rome, NY: Revere Copper Products, 2005. 11. Tremco Sealants. “Investigating Roof-to-Wall Connections through Industry Collaboration” (video). April 20, 2020. https://www.youtube.com/watch?v=QfwrPpcl5dE. 12. Build Meets World Blog. “An Architect’s Guide to Parapet-to-Wall Detailing”. October 2020. https://blog.buildmeetsworld.com/architects-guide-parapet-to-wall-detailing. 13. The Construction Specifier, Failures column. “It is time to saddle up! December 2020. 128 | Nagle IIiiBEC International Convention & Trade Show | September 15-20, 2021
