Masonry Magazine March 2012 Page. 36
MOISTURE MANAGEMENT
off the side of the flashing. If the window or door is near the base of the wall, the flashing should form a continuous envelope and be connected to the adjacent wall flashing.
Masonry copings
COPINGS CONSTRUCTED WITH stone, precast concrete, or masonry should not be considered watertight. Water can penetrate through transverse joints in the copings or be adsorbed directly through the coping unit. Parapets are subject to increased vulnerability from freeze-thaw distress because they are exposed to the elements on three sides. A flashing should be provided directly under the coping to block water from flowing down through the wall. Dowels or other types of coping anchor penetrations through the flashings must be sealed (see Figure 7).
Workmanship
ALTHOUGH MASONRY FLASHINGS can prevent water infiltration into buildings at certain locations, the overall workmanship of the mason has a large impact. One of the most common workmanship problems is mortar that falls down the inside of the drainage cavity. The mortar can harden and block the flow of water out of the weeps. Mortar droppings can also collect on wall ties and provide locations where water can bridge across the drainage cavity. Drainage composite materials are available. These mesh-like materials are placed at the bot-cavity, it will cover the top of the drainage composite.
ScaffoldMart
DI 65 Scaffold
Plank
2"x10" lengths 4-16 ft
SPIB Graded/Stamped
Rod, Clip, Name
imprint avail
Large inventory
LAP LATER RESISTIVE
BARBIEL OVER TOP OF
BACK JAL
FILTRATIONS
FLASH W
DEPS
Figure 7.
Conclusion
FLASHINGS ARE a critical component to the overall water management performance of masonry wall systems. All parties, including the owner, designer, general contractor or construction manager, and sub-contractors, must be aware of the critical nature of these flashings. During the inevitable value-engineering process, modifications are often made that can either eliminate some of these flashing components or substitute materials that may not perform as well as originally intended. Designers must be knowledgeable enough to educate the owner as to the advantages and disadvantages of these proposed substitutions. There is also a coordination burden placed on the general contractor and/or construction manager and various subcontractors, as more and more portions of the exterior building envelope are constructed by different entities. IMAS
ScaffoldMart
Sales/Quick Quote:
Jerry 252-341-6790 M anytime
Gray 704-650-2505 M anytime
866-900-0983 toll free
READER SERVICE #232
Douglas R. Stieve, RRC, AIA, is a registered architect in the states of Connecticut, Massachusetts, New Jersey, New York, and Pennsylvania. He is a member of RCI, AIA, and ASTM and has served on the ASTM C15.02, Brick and Structural Clay Tile Committee; and ASTM C15.04, Research (Masonry) Committee.
Reprinted with permission from the August 2007 issue of RCI's Interface technical journal. RCI is an intemational association of building envelope consultants. Its members specialize in design, investigation, repair, and management of roofing, exterior wall, and waterproofing systems. The association's 2,600 members are found throughout the United States and Canada. Educational programs, professional registrations, and technical publications are primary products of RCI.
RCI members are recognized for their professional expertise and adherence to an ethics code that offers consumers assurance of unbiased, objective consulting service. The associations' professional registrations: Registered Roof Consultant (RRC), Registered Roof Observer (RROJ and Registered Waterproofing Consultant (RWC), Registered Exterior Wall Consultant (REWC), and Registered Building Envelope Consultant (RBEC) are preferred standards for those of the consulting profession. For more information, visit www.rol-online.org.
34 MASONRY March 2012 www.masoncontractors.org
The Voice of the Masonry Industry