Architectural Coating Systems COMMERCIAL GLAZING GUIDE GLAZING GUIDE INTRODUCTION For more than 85 years, Tremco has been a market leader in the design, development and manufacture of glazing products for use in commercial construction applications. During this time, processes have changed dramatically for window and curtain wall systems. Window units have become larger, higher performing glass is available, and performance standards have increased — all placing a greater demand on the glazing materials used to seal and support the glass to or within the surrounding metal. As a result, we have continued to evolve, culminating in the development of our Sustainable Building Solutions Test Facility, which is designed for testing connection points in wall assemblies, as well as other building and design challenges facing the built environment. The only single-source supplier offering a complete line of glazing sealants, tapes, and gaskets, Tremco is focused on protecting the entire building envelope and ensuring product compatibility through documented, tested performance. Tremco also supplies compatible perimeter caulking and weatherproofing materials to complement your window or wall system. The details shown in this document describe available materials and their placement for generic applications and are not intended to reflect the actual design of the window unit or system. We recommend you work closely with your Tremco Representative. These experienced individuals will assist in the selection of the proper glazing materials to suit your application and project specification. 2 Factors Influencing Glazing Performance 4 Guidelines for Exceptional Glazing 6 Wet Glazing 8 Wet/Dry Glazing Systems 10 Dry Glazing Systems 12 Structural Silicone Glazing Integrated Systems 14 Sloped Glazing Designed for Superior 16 Plastic Glazing Performance 18 Protective Glazing 19 Hurricane/Impact Resistant Systems 20 Restoration 21 Reglazing Curtain Wall and Window Systems Tremco CS&W has nearly 50 products certified to GREENGUARD and GREENGUARD Children and Schools criteria. CONTENTS FACTORS INFLUENCING GLAZING PERFORMANCE Selecting the proper glazing or frost-laden surfaces. Two- differences in the coefficient of to varying dimensional changes system for a particular component sealants must be expansion between the infill and caused by fluctuations in requirement must take uniformly mixed before applying the sash. temperature and atmospheric into account a number of to achieve proper cure. Surfaces conditions. This imposes a important factors: to be caulked must be clean, Particular attention should be burden on the glazing system in dry, and free from contaminates directed to sash design and accommodating stresses Economics to ensure a good bond. Glazing dimensioning, sturdiness of the in tension, shear, and compression Life cycle costing is being used tapes must be butted (not sash, proper anchorage of the while maintaining a positive bond more and more to determine overlapped) at corners. Setting framing members, and the use of a to sash surfaces as well as to the the total cost over a specified blocks, spacer shims and edge high performance glazing system. glass or plastic sheet. period of time. What may blocks should be installed seem to be an economical properly when and where they Today’s high-performance glass Projected, pivoting, sliding, and glazing component in terms are required. Window washing products such as reflective, other operating sash create of initial costs, may eventually should not be done until sealant heat absorbing, insulating and further demands on the glazing become more expensive systems have been allowed to laminated place severe strains seals due to tracking, distortion, should it require frequent (and fully cure. on the glazing seals. Heat shock and vibration - as compared costly) maintenance, special absorbing glass, for example, to non-operating sash. installation and/or replacement. It is important to remember transmits higher temperatures Additional design considerations that the finest workmanship can to the glazing seal than In high rise construction, never compensate for poorly does clear glass. This may this situation can become designed or “light gauge” sash, dramatically shorten the service particularly acute. The cost improperly specified sealant, life of lower performance of frequent maintenance or adverse weather conditions, or sealants such as oil and replacement is more than the damage by trades not directly solvent based sealants. High- initial cost of installing a higher engaged in the glazing operation. performance glass requires the performance glazing system. use of high-performance Sash and Pocket Dimensions glazing seals. Conversely, the selection of The design and dimensions an expensive glazing system of the sash can dramatically Type of Sash may not be necessary on single affect the ability of the glazing All types of sash-PVC, steel, story structures or buildings system to properly perform. aluminum, or wood-are subject Sash joinery must be properly sealed. that afford protection from the Specifically, minimum face elements. In the final analysis, clearances as recommended a careful determination should by glass manufacturers, or be made between the glazing greater as determined by the Principal Causes of Glazing Failures system’s initial cost and its glazing system requirements. anticipated service life before a These clearances allow the • Glazing at temperatures below 40 °F (4 °C) final selection is made. glazing system to withstand • Failure to properly seal miter and butt joints the dynamic forces of shear, • Glazing pocket not clean or free of contamination Workmanship tension, and compression. In • Lateral shifting (“walking”) of glass Any glazing system, regardless the case of gunnable sealants, of its initial cost, must be the sealant configuration and • Failure to properly bed, cushion, or center the glass properly installed if it is to the volume of the sealant that • Use of glazing system not suited for sash design and achieve its maximum are required to be installed are performance requirements performance capability. important. A larger volume of • Setting blocks used incorrectly, or not at all The most expensive system, sealant (wider face clearance) • Frames or surrounds out of plane, out of square, improperly installed, will is better able to absorb and and/or improperly anchored. perform no better than an compensate for stresses and inexpensive system. strains as compared to smaller • Lack of, or improper use of, spacers or edge blocks volume of sealant. • Insufficient face clearance Similarly, the use of an • Damage to sash or stops or glazing seals inexpensive system does not Type and Size of Glazing • Improper pocket depth justify poor workmanship if the The larger the lite of glazing, the system is expected to properly greater the stresses placed on • Poor workmanship perform. For example, sealants, the glazing system. This is due • Failure to follow manufacturer’s instructions regardless of costs, will not to movements of the infill in the • Failure to ensure compatibility of glazing components bond properly to dirty, damp, sash caused by deflection, and 2 COMMERCIAL GLAZING GUIDE include, but are not limited to, Moisture accumulating in the Thermal breaks provide Tremco sealants are commonly whether or not the system will be sash may affect the bond of some excellent energy efficiency by used when point or full contact shop glazed, field glazed, or how sealants. This is particularly resisting condensation and with thermal breaks is required. glass replacement will be handled. true during freeze-thaw cycles reducing conductivity of heat and All removable glazing stops must or in areas of high humidity or cold thru metal systems. Often In the final analysis, proper be designed to properly support frequent precipitation. Drainage these thermal breaks possess glazing is a compromise the glass for the required wind systems are normally employed a certain chemical composition between the ideal criteria for load conditions. to effectively address this problem that sealants may not adhere to. effective glass support, and and will be discussed later in the practical considerations Weather Conditions this publication. of economics, tolerances and Glazing seals are subject to proper installation. physical changes caused by Moisture accumulating in the variations in both temperature sash may affect the bond of some and humidity. When glazing at sealants. This is particularly temperature below 40 °F (4 °C), true during freeze-thaw cycles the sash and infill may be damp or in areas of high humidity or or frost-laden, preventing a frequent precipitation. Drainage sealant from attaining a systems are normally employed satisfactory bond. Normal curing to effectively address this of sealants is slowed when problem and will be discussed subjected to low temperatures. later in this publication. As Tack-free time is extended, energy efficiency becomes a possibly subjecting the sealant greater factor in the design to additional dirt pick-up. and performance of windows and curtain walls, material used as thermal breaks become more prominent in these systems. Glass to sash contact may result in glass beakage. PRODUCT APPLICATION Sash joinery must be properly sealed. Spectrem® 1 High moving joints in curtain walls, precast concrete panels, window perimeters, cap beads, and bonding silicone gaskets. Spectrem® 2 Versatile caulking/glazing sealant for 2-sided structural glazing, cap/heel/toe