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 Mobile ViewEXTERIORS of buildings ALGAE, FUNGUS, LICHENS, MOSS ARCHITECTURE & BUILDING COMPONENT ID ATTIC CONDENSATION CAUSE & CURE BASEMENT WATERPROOFING BEST CONSTRUCTION PRACTICES GUIDE BRICK VENEER WALL Loose, Bulged BRICK WALL DRAINAGE WEEP HOLES BOOKSTORE - EXTERIORS CHIMNEY INSPECTION DIAGNOSIS REPAIR DECK & PORCH CONSTRUCTION DECK COLLAPSE Case Study DECK FINISHES COATINGS PRESERVATIVES DECK FLASHING LEAKS, ROT Case Study DEFINITIONS of ENGINEERED WOOD OSB LVL etc EARTHQUAKE DAMAGED FOUNDATIONS ENERGY SAVINGS in buildings ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY EXTERIOR WALL SIDING TRIM & FINISHES FIBERGLASS INSULATION FIBERGLASS HAZARDS FIBERGLASS INSULATION MOLD FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FRAMING DETAILS for BETTER INSULATION FRAMING DETAILS for DOUBLE WALL HOUSES FRAMING METAL STUD PERFORMANCE FOUNDATION WATERPROOFING FRENCH DRAINS HEAT TAPES & CABLES on Roofs for Ice Dams HOUSEWRAP AIR & VAPOR BARRIERS KIT HOMES, Aladdin, Sears, Wards, Others LEAD POISONING HAZARDS GUIDE LEAD PAINT REMOVAL ALTERNATIVES LEAD PAINT REMOVAL TROUBLES LEAD PIPES in BUILDINGS LEAD in ROOFING, EFFECTS LEAD TEST KIT for HOME USE LEED GREEN BUILDING CERTIFICATION LOG HOME GUIDE LIGHTNING PROTECTION MOISTURE CONTROL in buildings MOLD DETECTION & INSPECTION GUIDE MVOCs & MOLDY MUSTY ODORS ODORS & SMELLS DIAGNOSIS & CURE PAINT ANALYSIS, DIAGNOSTIC USES PAINT & STAIN GUIDE, EXTERIOR PAINT FALURE, DIAGNOSIS, CURE, PREVENTION PAINT FAILURE CHECKLIST PORCHES & Sunrooms PORCH CONSTRUCTION & SCREENING SHEATHING, Gypsum board SHEATHING Homasote & Other Board SHEATHING, OSB SHEATHING, Plywood SHEATHING, FOIL FACED - VENTS SIDING, Sheathing Identification - Photo Guide SIDING, ALUMINUM SIDING, ASBESTOS CEMENT SHINGLES SIDING ASPHALT ROOF SHINGLES on WALLS SIDING ASPHALT SHINGLE or SHEET SIDING DAMAGE by SPLASHBACK SIDING EIFS & STUCCO SIDING, FIBER CEMENT SIDING HARDBOARD SIDING STEEL SIDING VINYL SIDING, WOOD PRODUCT CHOICES SIDING, WOOD INSTALLATION SIDING WOOD, FAILURES OVER FOAM BOARD SIDING WOOD, FLASHING DETAILS SIDING WOOD SHINGLE INSTALLATION STAIN & BIODETERIORATION AGENT CATALOG STAINS on buildings - QUICK GUIDE STAIN DIAGNOSIS on BUILDING EXTERIORS STAIN DIAGNOSIS on BUILDING INTERIORS STAIRS, RAILINGS, LANDINGS, RAMPS STONE CLEANING METHODS STUCCO WAll FAILURES DUE TO WEATHER STUCCO WALL METHODS & INSTALLATION STUCCO OVER FOAM INSULATION STUCCO PAINT FAILURES SURFACE GRADING, SITE DRAINAGE TERMITES, ROT THERMAL EXPANSION of MATERIALS THERMAL MASS in buildings VAPOR BARRIERS & CONDENSATION in buildings ATTIC CONDENSATION CAUSE & CURE BASEMENT CEILING VAPOR BARRIER CONDENSATION or SWEATING PIPES, TANKS CRAWL SPACE VAPOR BARRIER DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE FELT 15# ROOFING, as HOUSEWRAP/VAPOR BARRIER HOUSEWRAP AIR & VAPOR BARRIERS HOUSEWRAP INSTALLATION DETAILS HOUSEWRAP PRODUCT CHOICES HOUSEWRAP at SILLS, SOLES, TOP PLATES HUMIDITY LEVEL TARGET MOISTURE CONTROL in buildings RAIN SPLASH-UP SIDING DAMAGE VAPOR BARRIERS & AIR SEALING at BAND JOISTS VAPOR BARRIERS & CONDENSATION in buildings VAPOR BARRIERS & HOUSEWRAP VAPOR CONDENSATION & BUILDING SHEATHING WATER BARRIERS, EXTERIOR WOOD SIDING FLASHING DETAILS VENTILATION in buildings WALL FINISHES INTERIOR WATER BARRIERS, EXTERIOR BUILDING WATER ENTRY in buildings WIND ENERGY SYSTEMS WIND TURBINES & LIGHTNING WIND WASHING INSULATION At EAVES WINDOWS & DOORS ALUMINUM WINDOWS Best Practices Guide for Windows & Doors: CLIMATE, WINDOW CHOICES FOR CONDENSATION on WINDOWS & SKYLIGHTS Doors, Exterior, Energy Efficiency Guide Doors, Exterior Flashing Details Doors, Exterior, Frames DOORS, EXTERIOR, Selecting & Installing DOORS, INTERIOR FIBERGLASS WINDOWS GLASS vs HEAT MIRROR SOLAR GAIN/Loss HURRICANE, WIND, & STORM-Resistant WINDOWS LOW-E WINDOW GLAZING LOW-E VS QUAD-GLAZING LOW-E RETROFIT ADD-ON FILMS POLYCARBONATE GLAZING SITE BUILT DOUBLE GLAZED WINDOWS SKYLIGHTS, Guide to Choosing & Installing Skylight Condensation Problems Skylight Window Design Issues Skylight Energy Efficiency Skylight Installation Procedures SKYLIGHT LEAK DIAGNOSIS & REPAIR SKYLIGHT VENTILATION DETAILS SLIDING GLIDING WINDOW DEFECTS SLOPED GLAZING DETAILS STORM WINDOW INTERIOR STORM WINDOW PLASTIC CHOICES STORM WINDOW WEEP HOLES SUNGAIN, FILMS, LOW-E GLASS SUNSPACE GLAZING for SUNTANNING VERTICAL GLAZING DETAILS VINYL WINDOWS VINYL / PVC WINDOW WARPING WINDOW / DOOR ENERGY EFFICIENT, DOE WINDOW / DOOR AIR LEAK SEALING HOW TO Window Certification WINDOW EFFICIENCY Features & Ratings Window Flashing & Sealing Guide WINDOW HARDWARE PHOTOS Window Installation, Flange-Type Window Installation, w/ Integral Brickmold WINDOW LEAKS INTO BASEMENT Window Materials & Construction Window Types, Guide WINDOW TYPES - Photo Guide Window & Door Sources WINTERIZE A BUILDING WOOD Burning Heaters Fireplaces Stoves WINTERIZE A BUILDING WOOD Burning Heaters Fireplaces Stoves More Information |
This article discusses the proper installation details for vertical glazing: fixed vertical window glass on buildings. Sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. The problems inherent in vertical glazing (discussed here ) are multiplied in sloped glazing - readers should also see SLOPED GLAZING DETAILS. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. How to Install Fixed Vertical Window Glass"Fixed Vertical Glazing: less demanding than sloped glass, it still takes careful detailing" - links to the original article in PDF form immediately below are followed by an expanded/updated online version of this article.
Mr. Bliss points out that many carpenters are accustomed to installing pre-hung windows and doors, but are not experienced or trained in the details of successful installation of fixed double glass windows. The text below paraphrases, quotes-from, updates, and comments an original article original article (see links just above)"Fixed Vertical Glazing" by Steven Bliss. Our photograph (left) shows two triangular double-glazed vertical fixed glass windows installed by Daniel Friedman in the gable-end wall of this workshop. These vertical fixed glass windows were made by a local window glazing company to dimensions chosen to fit in the framed window opening leaving the clearances discussed below. What are Insulated Glass Units & How do They Work to Save Energy?An insulated glass window unit is made from two or more panes of glass bonded to an aluminum spacer. The spacer itself is filled with a desiccant - a material that absorbs moisture from the air to dry out the space between the panes. The glass panes are sealed to the dessicant-filled spacer using polysulfide, polyisobutylene, silicone, urethane or other sealants. Premium sealed glass units may use two sealants: an inner seal of butyl as that material provides both a strong mountant and an effective moisture seal, and an outer seal of silicone. How Condensation and "Fogging" Occurs in Sealed Glass Windows
If improper assembly or improper window installation causes the window glass seal to leak, allowing new moist air to enter the glass space, the desiccant will eventually be overwhelmed and foggy condensation can appear on the interior of the glass. Our photograph (left) shows a vertical fixed glass bay window that whose seals failed, leading to condensation and fogging between the window panes. As the sealed glass window is exposed to varying temperatures and to air of varying moisture levels, warm moist air can be drawn into the space between the glass panes, followed by moisture condensation on the interior glass surfaces. As the window is exposed to cycles of temperature changes, the amount of moisture between the panes accumulates until ultimately the leaky previously-sealed glass widow becomes fogged and even opaque. Common sealed glass failure modes are
And see SLOPED GLAZING DETAILS for a discussion of how thermal expansion and contraction can lead to damage and leaks in various window glazing systems. How to Handle Insulated Glass During Window InstallationA double-glazed window unit built using 3/16" thick glass weighs over five pounds per square foot. Such window units should be handled with extra care and plenty of hands - at least two workers for vertical glass. Any nicks or scratches in the glass will weaken it significantly by compromising the tensile strength of the glass surface. Tempered glass is a little easier to handle as it is less fragile and because its edges are sanded smooth. If you are installing lots of glass, buy the suction cups that professional glaziers use to handle glass units and to place them accurately into their final position in the window frame. How to Construct the Frame for Vertical Fixed Glass InstallationsTake the time to frame accurately, particularly if the framing is also the finish, as is often the case in a sunspace. Check the opening for squareness by comparing diagonal corner-to-corner measurements or use a full-size template. Check that the window opening is in plane by sighting, or design a system with stops that can be adjusted after the glass is set. Forcing the glass into an out-of-plane opening guarantees a short life - glass failure mode No. 2 that we described above. There are many ways to set up the openings. Unless maximum glass area is required, I like to have a separate frame that can be shimmed or adjusted. The finish opening should be 1/2-inch larger than the glass unit in each dimension, thus leaving 1/4" around all sides of the glass. The rabbet (or stops) should be 3/4" thick to allow a 1/2" bite against the glass plus the 1/4" clearance. The goal is to have the glass floating in the opening with a space on all sides and edges. This float space is what prevents damage to the glass by forces exerted by building weight or flexing. The frame can be built out of rabbeted 2-by stock or 1-by stock with separate stops. A 2-by frame can be its own finish (interior and exterior) if left projecting past the drywall on the interior and siding on the exterior. In either case the bottom of the jamb should be level where the glass bears and should be beveled to shed water on the exterior. In a humid space such as a greenhouse, the interior sill should also be sloped to shed condensing water. The Glazing System - Installation Details for Fixed Vertical Window Glazing
The glass should sit on two 4-inch long hard neoprene glass-setting blocks obtained from the glass distributor. Set these window glass blocks a quarter of the way in from either end. If necessary, one block can be shimmed (from below) with a non-compressible material such as metal flashing. The glass setting blocks should be a little wider than the thickness of the glass to ensure continuous support of both lights (panes) of glass. The neoprene setting blocks are shown in the center of the illustration at left. Once the glass has been fit and centered and its position marked, remove it carefully and peel back the paper facing by holding one finger on the paper as you go. Then set the glass in position. The glass unit must not touch the framing - that could transmit structural loads to the glass (insulated glass failure type #2 above). Compressible foam or rubber spacers can be used to help center the glass in the opening. Next place the glazing tape on the glass and install the finish stops or battens. The stops should be set to compress the window glazing tapes by 35 to 50 percent. For example, if the glass is 1-inch thick, and the glazing tapes are 1/4-inch thick each, the overall rabbet should be 1 1/4 inches deep - compressing the glazing tape by 50 percent. I (DJF) like to also cut the exterior stops with a slight bevel cut to assure that wind-blown rain running down the glass drains readily off of the stop, prolonging its life. Install the finish stops with the greatest of care, protecting the glass from tools, nails, and screws with ample pieces of fiberboard, hardboard, or any non-abrasive material. Point nails away from the glass and watch out for knots or grain in the stop wood that might deflect a nail towards the glass. It's a heart breaker to see a large triple-glazed tempered window shatter into thousands of tiny fragments due to a wayward nail. I speak here from experience. A secondary seal of silicone caulking should be installed on the exterior, sealing from glass to stop. If neatness is a consideration, use masking tape and tool the bead to the tape. Remove the tape after the caulk has skinned over. Remove excess silicone from the glass with a razor. Paint the wood first or use a pigmented or paintable caulk. Glazing is best done when the temperature is above 40 deg. F. outside. Below that condensation may form on the glass, preventing a good seal to the butyl. If you must, dry the glass with a solvent-dampened rag just before installing the butyl tape. The glass should be cleaned with solvent (such as alcohol) anyway where it seals to tape or caulks. One final consideration for a high-quality glazing job is the need for weep openings. The purpose of weeping a glazing system is to allow any water that penetrates the system to escape. If it remains trapped it will tend to undermine the sealants and could diffuse into the sealed glass unit causing fogging (failure type #4 above). You can allow for weeping by drilling small holes (1/4" diameter) at a downward angle from beneath the glass to the outside through the bottom of the stop. Be very careful to drill low enough to completely miss the edge of the glass or you'll break the window. The weep opening should drain across the sloped sill and away from the building. Readers should also see SLOPED GLAZING DETAILS where we describe the use of window glazing tapes, dry gaskets, caulk, and neoprene setting blocks in more detail. Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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