Masonry Magazine February 2010 Page. 28
MOISTURE MANAGEMENT
Thicker film build allows for the encapsulation of aggregate for aesthetics and masking surface imperfections.
Today's high build coatings formulated for use on masonry substrates can tolerate the naturally higher pH of masonry substrates better than most paints.
High build coatings provide equal or better aesthetic and color range compared to typical paints.
High build coatings are more durable and will physically last longer than thin film materials.
Protective wall coatings
Protective wall coatings are effective tools in the fight to protect buildings from moisture. When buildings leak, protective wall coatings can be part of a system solution to correct the problem and to provide long-term protection for the building.
Coating repairs that last
PROTECTIVE WALL COATINGS provide many benefits to buildings; however, they are not a substitute for proper detailing and good workmanship. Buildings leak for several reasons. A systems approach that provides redundancy in moisture protection is often the best solution. Long lasting repairs begin with assessment to determine the cause of the problem. Most masonry buildings, particularly older ones, require a combination of repairs.
Buddy™ by Stone
America's Fastest & Strongest Mortar Mixers
It's Not The Mixer, It's
The Quality Of The Mix
Four models of extreme-duty mixers for specialty mix applications:
Capacities to 13 cu. ft. / 5 bags
Extremely efficient patented drum geometry and paddle configuration improves the mix quality by increasing the entrained air.
Exclusive Symmetrical drum dramatically increases drum strength and improves mixing efficiency by eliminating the "Dead Zone".
Please Call
Dynamic Mixing 800-888-9926
or visit our website
www.stone-equip.com
Stone
STONE CONSTRUCTION EQUIPMENT, INC.
8662 MAIN STREET
HONEDYE, NY 14471-0150
E-MAIL: SCENYSTONE EQUIP.COM
PHONE:
FAX:
1-800-888-9926
+1-585-229-5141
+1-585-229-2363
26 MASONRY
READER SERVICE #217
A primary suspect in moisture infiltration is mortar - either because of cracking joints, settlement, or clip joints. Regardless of the cause, damaged mortar should be repaired before the application of a wall coating. Cracks larger than 1/32 inch, signs of rust bleed, or efflorescence are indicators of problems. Additionally, mortar should be struck concave and smooth. Raked or beaded joints should be avoided on exterior masonry. Damaged masonry units should be repaired or replaced using compatible materials.
With both cavity walls and single wythe walls, drainage is an important element of a properly functioning wall. Even with the best design and workmanship, moisture can find its way into the wall section. Flashing and weeps are a critical component of any wall system. Damaged and missing flashing should be replaced. Care should be taken to ensure that weeps are not coated over or obstructed.
Other areas that can contribute to moisture ingress are sealant joints, penetrations, window perimeters and parapet caps.
Selecting the right material
NOT ALL MATERIALS are appropriate for all substrates or applications. Masonry and concrete masonry are unique substrates with unique requirements. Efforts to save money often go unrewarded when projects need to be recoated because an inexpensive paint was used in place of a protective coating (and subsequently fails).
When selecting a material, it is important to choose one that is formulated for use on concrete, masonry and concrete masonry. Masonry substrates can be high in pH, which can cause certain types of materials to fail prematurely. Using a material that was not formulated for use on masonry can lead to premature color fade, chalking and delamination of the coating.
Vapor permeability also is an important attribute of a wall coating. While preventing moisture from getting into the substrate, a protective wall coating also must allow moisture within the substrate to escape. A coating functions much in the same way our skin functions, it is waterproof while still allowing our bodies to perspire. When selecting a material, it is important to evaluate the test data provided by manufacturers and verify that the mil thickness used to report permeability is the same mil thickness that is recommended for the application of the coating. Reporting a high permeability value is meaningless if the recommended coating application is significantly thicker.
Once a material has been selected, it is a good idea to have a mock-up installed on the building. Mock-ups provide validation of the compatibility of the coating with the substrate and provide an example of workmanship. It is important that the mock-up be installed in an area that is representative of the substrates to be coated and be allowed to remain until the end of the project. The February 2010 www.masoncontractors.org
The Voice of the Masonry Industry