Exterior Insulation System Research Articles

Design of Engineered Drainable Exterior Insulation and Finish System (EIFS) Cladding

Abstract During the last ten years, the authors have investigated a number of buildings with leakage and deterioration problems associated with exterior walls clad with exterior insulation and finish systems (EIFS). These systems were “barrier” walls applied to materials that degrade rapidly from exposure to moisture, such as gypsum board sheathing. These wall systems lacked backup waterproofing and flashing elements and relied on surface seals as the sole means of controlling water penetration (leakage). While these systems are appealing due to their aesthetic features, light weight and insulating characteristics, they are vulnerable to performance problems as a result of failed surface seals, leakage through window frame corners and poor installation practices. Installation of internal flashings is difficult at best because the primary waterproofing layer (the lamina) is on the face of the cladding rather than in the plane of the flashing. In this paper, the authors review the essential differences between barrier and drainable EIFS. The primary focus of the paper is to examine the various components of an engineered drainable EIFS including waterproofing membranes, drainage plane grids, methods of attachment, and consideration for use of a vapor retarder (position) within the wall cross section. Detailing of wall penetrations, particularly for windows and doors will be presented as will location of flashings and weep mechanisms in multi story construction. Design considerations will be illustrated in two case studies where barrier EIFS was replaced with an engineered drainable system, one in a relatively warm climate (southern California) and the other in a relatively cold climate (Massachusetts).

Retrofitting Barrier Exterior Insulation and Finish System: Methodology and Performance Assessment

Abstract Barrier-EIFS (exterior insulation and finish system) refers to EIFS with no internal drainage plane or through-wall flashings to collect and drain water that bypasses the EIFS’s surface barrier. EIFS’s surface barrier consists of a thin lamina and exposed joint sealants at transitions to elements such as windows, projecting decks, and intersecting parapets to prevent water infiltration through the surface barrier. Breaches in the surface barrier, however, can cause water leakage into the wall and building interior. In some cases reasonable reduction of leakage and preservation of the exterior walls may be accomplished by reducing barrier-EIFS’s over-reliance on sealants, and by introducing watertight through-wall flashings at leakage-prone transitions and penetrations. The authors refer to this approach—providing flashings and localized drainage immediately around transitions and penetrations of wall elements while maintaining or improving the existing barrier-EIFS system away from such details—as “hybrid repairs.” A case study of repairs on an existing high-rise barrier-EIFS-clad building shows the in-service performance of the hybrid repair methodology. The subject building had experienced water leakage at intersections of the EIFS and other building envelope elements, including windows, doors, balcony deck-to-wall transitions, and intersecting parapets. Repairs to correct water leakage focused on creating reliable concealed flashings at these details, along with more common barrier-enhancement repairs over the original EIFS, which was generally left in place. To help evaluate the hybrid repairs’ effectiveness, the authors surveyed typical exterior repairs in place for 2–1/2 to 5–1/2 years and interior finishes in the areas of the repairs. The Authors interviewed residents in some units that had experienced chronic water intrusion prior to the repairs; residents commented that they have seen no water intrusion since the repairs. The survey and interviews with residents revealed no evidence or reports of reoccurring water intrusion, supporting the general effectiveness of the hybrid repairs on the subject building.

Externally Insulated (“EIFS”) Building Walls: Security Characteristics and Methods of Enhancing Security Performance

Abstract Approximately 10% of new commercial buildings in the United States use Exterior Insulation and Finish Systems (“EIFS”) on their exterior walls [1]. This includes buildings of almost all types from small residences to large commercial structures in both the public and private sector. EIFS is also used extensively overseas [2]. Although EIFS looks like concrete and appears robust, the lightweight materials in EIFS are not inherently conducive to physical security, electromagnetic security, and fire exposure. This is often overlooked in the planning phase for new buildings, leading to buildings that do not meet current expectations for security-related performance. However, ways exist to beef up EIFS walls so that better performance can be attained. This paper will explore the state-of-the-art of the security aspects of EIFS when used over various types of supporting walls. Key design aspects of EIFS-clad walls will be explained, including the need for attention to the supporting wall structure, the choice of EIFS materials, and the addition of special materials to enhance performance. Examples of new wall designs and enhancing existing walls will be presented.

Evaluation of Exterior Insulation and Finish System Fire Hazard for Commercial Applications

To judge existing fire test methods in use or those planned/proposed for use withexterior insulation and finishsystem (EIFS) products, a critical commercial/industrial accident scenario has been id...

Mortality among unionized construction plasterers and cement masons.

Plasterers perform a variety of duties including interior and exterior plastering of drywall, cement, stucco, and stone imitation; the preparation, installation, and repair of all interior and exterior insulation systems; and the fireproofing of steel beams and columns. Some of the current potential toxic exposures among plasterers include plaster of Paris, silica, fiberglass, talc, and 1,1,1-trichloroethylene; asbestos had been used by the plasterers in the past. Cement masons, on the other hand, are involved in concrete construction of buildings, bridges, curbs and gutters, sidewalks, highways, streets and roads, floors and pavements and the finishing of same, when necessary, by sandblasting or any other method. Exposures include cement dust, silica, asphalt, and various solvents. Proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were calculated for 99 causes of death among 12,873 members of the Operative Plasterers' and Cement Masons' International Association who died between 1972 and 1996 using United States age-, race-, and calender-specific death rates. Statistical significance (P value) of results was based upon the Poisson distribution. Among plasterers, statistically significant elevated mortality was observed for asbestosis, where the PMR reached 1,657 (P < 0.01) with eleven observed deaths and less than one death expected, for lung cancer (PCMR = 124, P < 0.01), and for benign neoplasms (PMR = 210, P < 0.05). Among cement masons, statistically significant elevated mortality was observed for cancer of the stomach (PCMR = 133, P < 0.01), benign neoplasms (PMR = 132, P < 0.01), and poisonings (PMR = 159, P < 0.05). Except for poisonings, which were not thought to be occupationally related, all of the statistically significant results occurred among those members who entered the union prior to 1950. However, the risk for lung cancer among plasterers was still elevated among those entering the union after 1970 as was the risk for stomach cancer among cement masons who entered the union after 1950. The present study suggests that plasterers and cement masons still have elevated risks for certain diseases, especially lung and stomach cancer. Therefore, union members currently living should be screened for asbestos-related diseases and educated about the future risks for these diseases.

Mortality among unionized construction plasterers and cement masons

Background Plasterers perform a variety of duties including interior and exterior plastering of drywall, cement, stucco, and stone imitation; the preparation, installation, and repair of all interior and exterior insulation systems; and the fireproofing of steel beams and columns. Some of the current potential toxic exposures among plasterers include plaster of Paris, silica, fiberglass, talc, and 1,1,1-trichloroethylene; asbestos had been used by the plasterers in the past. Cement masons, on the other hand, are involved in concrete construction of buildings, bridges, curbs and gutters, sidewalks, highways, streets and roads, floors and pavements and the finishing of same, when necessary, by sandblasting or any other method. Exposures include cement dust, silica, asphalt, and various solvents. Methods Proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were calculated for 99 causes of death among 12,873 members of the Operative Plasterers' and Cement Masons' International Association who died between 1972 and 1996 using United States age-, race-, and calender-specific death rates. Statistical significance (P value) of results was based upon the Poisson distribution. Results Among plasterers, statistically significant elevated mortality was observed for asbestosis, where the PMR reached 1,657 (P < 0.01) with eleven observed deaths and less than one death expected, for lung cancer (PCMR = 124, P < 0.01), and for benign neoplasms (PMR = 210, P < 0.05). Among cement masons, statistically significant elevated mortality was observed for cancer of the stomach (PCMR = 133, P < 0.01), benign neoplasms (PMR = 132, P < 0.01), and poisonings (PMR = 159, P < 0.05). Except for poisonings, which were not thought to be occupationally related, all of the statistically significant results occurred among those members who entered the union prior to 1950. However, the risk for lung cancer among plasterers was still elevated among those entering the union after 1970 as was the risk for stomach cancer among cement masons who entered the union after 1950. Conclusions The present study suggests that plasterers and cement masons still have elevated risks for certain diseases, especially lung and stomach cancer. Therefore, union members currently living should be screened for asbestos-related diseases and educated about the future risks for these diseases. Am. J. Ind. Med. 39:373–388, 2001. Published 2001 Wiley-Liss, Inc.

Exterior Insulation and Finish Systems: The Effect on Residential Housing Prices and Marketing Time

Recently, the use of artificial stucco (formally known as Exterior Insulation and Finish Systems, or EIFS) on residential real estate properties has been a topic of much debate. This article discusses the issues surrounding EIFS use. Hypotheses are developed and tested regarding the impact of EIFS on property value and marketing time. The results indicate that the market is not discounting EIFS clad homes, but that the presence of EIFS significantly extends a property's marketing time. These findings are consistent with the theoretical framework and are compatible with inefficient local real estate markets.

Long-Term, Hygrothermal Performance of Exterior Insulation and Finish Systems (EIFS)

To control rain ingress, the Exterior Insulation and Finish Systems (EIFS) can be constructed with one of two design principles • a drain screen (rain screen, pressure equalized rain screen-PER) approach • a face sealed (barrier) approach While the barrier approach has an inherently higher risk for moisture damage, it offers econormc advantages and may be successfully used under a multitude of cli matic and service conditions. Its performance evaluation is carried out in three steps: 1. Examine whether this system can be used for a specific set of climatic and use con ditions 2. Formulate necessary measures for material and field quality control in the design specifications 3. Examine the system for integrity under cycling environmental conditions and long-term performance Step 1 of this evaluation is based on the moisture control strategy of the whole wall assembly. Step 2 requires the addition of several small-scale material tests, and Step 3 involves full-scale system testing. The full scale testing is necessary to incor porate several parameters that act on the system simultaneously (thermal stress, thermal and moisture originated expansion and contraction, structural movements, material changes caused by weathering and aging, presence of moisture, etc.). The in teraction among these factors may provide conditions with severity significantly in excess of those achieved when these parameters are tested separately. This discussion paper consists of three parts: Part 1: Deals with the assessment of constituent materials of the EIFS with a view to ensuring (characterizing) hygrothermal performance of the system (by testing and characterization of the constituent materials, one may limit the range of variation in the hygrothermal performance of the whole system). Part 2: Postulates a new test for evaluation of EIFS integrity under simulated expo sure to climatic cycling. Part 3: Recommends EIFS design solutions and construction details for both new and retrofit construction. These details are discussed in the context of specific environmental/climatic conditions. This will be published in a later issue of JTIBE. Testing EIFS cladding systems for integrity under simulated exposure to climatic cycling involves preconditioning under simultaneous exposure to a water vapor gra dient and temperature gradient followed by exposure to severe conditions of one- sided, uni-directional climatic cycling. The testing and characterization of the con stituent materials (Step 1) coupled with the full-scale test for EIFS integrity under exposure to climatic cycling (Step 2) will increase the reliability of the EIFS systems in North America. Part 3 fills the gap between the current understanding of moisture control princi ples and construction practices. Many small changes in materials and technology create a compound effect that increases the frequency of inadequate field perform ance. Though most inherent EIFS flaws may be minor, those, when coupled with a number of failures of wall systems involving EIFS, caused an adverse attitude toward EIFS, perhaps more prevalent in some regions of North America. This paper pro vides a fundamental framework to cement many of the previously postulated correc tive measures into a coherent package aiming at the improvement of the EIFS reli ability in North America.

Cracking in Exterior Insulation and Finish Systems

The outside lamina of an exterior insulation and finish system is typically applied as a plaster using a polymer and portland cement mix, reinforced by a mesh that is usually a glass fiber product. Observations of leakage and cracking are discussed. Engineers sometimes find a particularly severe cracking failure in which the crack splits the system, including the mesh, fully through its thickness, suggesting that in such cases the mesh is of insufficient strength to distribute tensile strains and control cracking. Elementary stress analysis establishes the conditions under which such full splitting will occur. Pilot tests were performed to measure elastic modulus, rupture stress, shrinkage strain, and mesh strength. For the sample system studied, the measured properties confirm the mesh strength to be inadequate for control of cracking, and predict system performance failure by full splitting. Further analysis demonstrates that the tensile strain field producing such failure can be produced solely by shrinkage of the material.