Masonry Magazine June 2011 Page. 20
FLASHING AND DRAINAGE
KRANDO
METAL PRODUCTS
Est. 1987
ROFLAS
Stone Anchors
Flashing
On-Site Equipment
Drip Edge
Termination Bar
Dowel Caps
End Dams
Krando Metal Products, Inc. manufacturers all types of stone anchors, flashing and on-site machinery in our 61,000 Sq. Ft. state-of-the-art facility. All orders can be placed directly with Krando Metal Products, eliminating the need for a third party. All products are manufactured in house based on your job specification and requirements. Call Us Today To See How We Can Lower Your Cost & Lead Times!!! 610.543.4311 www.krando.com
READER SERVICE #227
18 MASONRY
Base flashing detail with a drip edge patented shapes to catch and break up mortar droppings at two distinct heights. This ensures a clear path for water to migrate around the droppings and out of the wall.
The concept of ventilating the cavity air space is another major development in our industry related to moisture management. The use of vents at the top of a cavity wall section combined with the weeps at the bottom of the section allow for the circular movement of air in and out of the cavity, allowing materials within the wall to dry out and provide the added benefit of more effective movement of moisture out of the cavity. Ventilation can be accomplished through the use of similar, full-height, weep-type materials or open-head joints. This ventilation concept also lowers the air pressure differential between the outside air and the air with the wall assembly, thus slowing down the moisture drive into the wall.
In southern climates, ventilation systems help to release excessive heat buildup within the cavity. The masonry industry now recommends a two-inch air space behind the brick to provide a clean, open area for any moisture to more easily work its way to the bottom of the cavity, onto the flashing material and out through the weeps. Some veneer products, especially stone, can have varying thicknesses, making it virtually impossible to maintain a consistent two-inch air space over the entire wall. Options like woven mesh material or drainage panels installed over the entire wall can provide a clear pathway for moisture to escape cavities that are considerably less than the recommended two-inch air space.
Obviously, masonry wall design has become increasingly complex, with so many components coming together in the wall assembly. Designers and specifiers must look at all of these materials and how they interact with each other to provide a complete system approach that can accomplish all the requirements of a current structure. Component manufacturers must be keenly aware of how all of these products must effectively function together, understanding products in addition to their own. Contractors have the ultimate responsibility of constructing these complicated wall systems to manage moisture and give the owner a building that meets today's high-performance standards. IMAS
Christopher Bupp is head of the Educational and Architectural Services Division for Hohmann and Barnard. He also serves on the Flashings and Terminations Committee of the Air Barrier Association of America.
June 2011 www.masoncontractors.org
The Voice of the Masonry Industry