MOISTURE EXPOSURE IN BUILDINGS
{"Image DocumentName": "MOISTURE EXPOSURE IN BUILDINGS", "Image ImageDescription": "Construction. First year. Remaining life. Key drivers. Weather. Wet construction processes. Site preparation & drainage. Job scheduling & logistics. Materials transport & storage. Dry out period for wet building materials. Poor construction. Occupancy & lifestyle factors. Poor design (e.g., condensation, leaks) Catastrophic events. Occupancy & lifestyle factors. Intrinsic moisture sources. Wet construction processes. Concrete & masonry. Poured flooring. Interior finishing. Wet construction processes. Concrete & Masonry. Structural framing lumber. Wet areas. Wet areas. Bathrooms. Kitchens. Indoor pools & locker rooms. To adequately understand & develop moisture control strategies, a building\u2019s life needs to be viewed in three critical stages: 1. Initial construction period. 2. Transition drying period during the first year of operation. 3. Operation & maintenance period over the remaining lifetime of the building The key drivers for moisture exposure during construction include Inclement weather, moisture introduced by wet construction processes, site preparation & drainage, job scheduling & logistics, and materials transport & storage. Intrinsic moisture sources involve materials that are installed wet & are inherent to the construction process. Concrete masonry, poured flooring, and interior finishing processes such as joint treatment, painting & hanging wallpaper are good examples. These introduce large amounts of moisture into the building that must be safely dried out & removed but occur only in the early stages of the building\u2019s life. Weather and episodic exposures such as a broken water pipe or other accident can soak materials and cause significant water accumulation at unpredictable times. Moisture accumulation can be alleviated or exacerbated by factors such as site drainage & flashing details. Certain materials, such as exterior sheathing & area separation walls, are unavoidably exposed to the weather during construction and require an added degree of robustness when rainy weather is possible. Likewise, wood framing can get soaked by rain, as can materials improperly stored or brought onto the site before the building is closed in, which adds to the intrinsic moisture loads and can lead to mold growth if the materials are not dried quickly. The first year after construction begins a transition period that must be considered in the moisture management strategy. Concrete basements and foundations will continue to release significant amounts of moisture for months to come and a safe path must be provided for this moisture to escape without accumulating where it can cause long term damage. Likewise, if the wood framing has gotten wet during construction, provisions to dry this out must be made to safely & quickly remove this moisture from the building. Poorly insulated or sealed elements of the exterior envelope will create cold spots that can result in condensation problems. The HVAC system (heating & air conditioning) can introduce myriad problems if the fans and ducts do not balance air pressures throughout the building or if improper drainage of cooling coils and drip pans lead to mold growth in the ductwork itself. Of course, leaky roofs, poor window flashings, and plumbing leaks can lead to serious problems when these details are not executed correctly. Finally, after the building has been fully dried out it still must handle moisture from the occupant activities, weather cycles and basic design & maintenance issues. Weather & other episodic exposures. Exposure to weather. Exterior sheathing. Shaft wall & Area separation walls. Structural framing. Building envelope leakage. Plumbing leaks. Building envelope leakage. Plumbing leaks. Avoidable. Poor design & construction. Poor mat\u2019ls staging & storage. Poor design & construction. Poor HVAC design. Improper HVAC operation. Poor maintenance & repair.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}