Masonry Magazine April 2007 Page. 40
FLASHING AND DRAINAGE
FLUSHING OUT
FLASHING
BASICS
BY JOSHUA J. SUMMERS, SE, PE AND KAMI FARAHMANDPOUR, PE, RRC, CCS, CCCA BUILDING TECHNOLOGY CONSULTANTS, PC
FLASHING IS A CRUCIAL COMPONENT IN MODERN MASONRY WALLS. Whereas solid, multi-wythe masonry walls - mostly constructed before the 1900s - manage water infiltration through absorption and evaporation, modern masonry walls must accommodate moisture penetration by providing a collection and drainage system. This system consists of flashing and weeps. Flashing also serves to prevent water penetration at interfaces with other building systems, such as windows and other penetrations.
Cavity wall design recognizes that water penetration through masonry is inevitable, and it provides the necessary means to manage moisture. Flashing location, material selection, detailing and proper installation are all significantly important to ensure that water does not penetrate to the interior areas of buildings.
Images Top to Bottom: Flashing seams or laps that are not property sealed can lead to water leakage.
Failure to properly install flashing at wall corners and intersections can lead to water leakage, and possibly mold.
End dams are often formed using a combination of flexible flashing with a sheet metal backup to ensure proper grometry of the flashing is maintained during construction.
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Masonry
April 2007
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