|• Cavity Wall Moisture Management|
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|• Stone Veneer|
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The Official Publication
of the Mason Contractors
Association of America
Managing Moisture in Masonry
Several new systems that keep moisture out of wall cavities have hit the market during the last couple of years, and they may have arrived at just the right time. More states are considering adding moisture-management requirements to their building codes.
"There's speculation that moisture management will become code in 28 states by the end of 2009," says Jeremy Douglas, VP of sales and marketing for Sandell Manufacturing Co. Inc. in Schenectady, N.Y.
Eliminating moisture in walls
"Our Driwall Rainscreen merely provides an air space between the veneer and the wall of the structure, so moisture can drain. What we provide is an air space for ventilation and drainage," O'Neill says. "We provide that cavity in a very cost-effective way."
The TotalFlash cavity wall drainage system from Mortar Net USA Ltd. offers complete moisture management in a single panel, says Earl Bickett, general manager for the Gary, Ind.-based company.
Each panel features a no-clog drainage matte that allows water to pass to the weep taps. A stainless-steel drip edge releases moisture away from the building, while weep taps channel moisture to the outside of a building. Mason contractors don't have to worry about clogging the weep holes.
"The mesh will not clog with mortar," says Bickett. "The mortar goes over the weep tabs, and then leaves a dent in the mortar. The mortar leaves a void, and the mesh is a continuous drainage plane, then water exits through the weep holes. You work over the weep hole like it's not even there."
Bickett says TotalFlash can be being used for any type of commercial building, such as offices, condos, hospitals and schools.
Sandell's Air-Tight Liquid is a spray-on or fluid-applied waterproofing membrane that's applied to the exterior side of masonry foundation walls. It lets moisture pass through, but retains heat.
"What makes the product unique is that some products require a two-week wait period," Douglas says. "Our product is completely cured in 24 hours."
A new approach
"Rubber asphalt has a low melting point. If you extend it to the end of the wall, that wall can get warm enough to melt the asphalt," Bupp says. "Asphalt will melt out between the brick joints and run down the face of the building."
Although a drip plate can solve the bleed-out problem, not everyone likes to use them, he says. "Some builders and architects don't want to use a drip plate because of the stainless-steel line running through the face of the building."
The company's clear adhesives can withstand higher temperatures than asphalt without melting. "The clear adhesives have a much, much higher melting point," Bupp says. "They have a melting point of 350 degrees. That pretty much eliminates that melting problem."
Hohmann & Barnard also took a new approach to drip edge. Flex-Flash is a three-inch wide membrane that's tough enough to resist tears, yet stays flexible, even in extreme hot or cold temperatures. Available in five colors to match mortar or brick colors, the drip edge is not susceptible to degradation from the sun's ultraviolet rays.
"The product can be brought tight to the edge, because it isn't affected by UV rays," Bupp says. "We can make it in different colors to match the building so it disappears."
Keene designed its Driwall mat to be used in a wide range of applications, including brick, stone and masonry, which means installers don't have to switch products for different areas of the building, O'Neill says.
"This makes it easy for the spec writer. They only need to specify one system," he says.
Driwall works for a variety of traditional veneers on hotels, restoration projects, and light commercial buildings.
Faster installation, less labor
Since the flashing panels are pre-cut into five-foot long lengths, mason contractors don't have to waste time cutting rolls of flashing, Bickett says. A single worker screws the fully assembled panels, which have pre-drilled holes, to the back of the wall cavity, which can be done in seconds. Since all of the moisture management components are built into each panel, contractors don't have to waste time ordering and then waiting for separate items to arrive on the jobsite.
"It's a big time and money saver," he says. "Contractors like it because there are no callbacks. Callbacks are horribly expensive. It is a total flashing system. We've taken components of traditional flashing and put them all together in a single panel."
Besides cutting installation time, TotalFlash is almost fool-proof to attach to walls, Bickett says.
"The idea is to reduce the opportunity for errors and omissions. The panel design takes the guess work out of installation. This is easier to put together right than to do it wrong," he says. "The opportunity for error is reduced."
Sandell's Douglas says the Air-Tight air barrier also offers fast installation. It can be brushed, rolled or sprayed into buildings quickly.
"I've seen the product go up on a dorm building in one day," Douglas says. "It's quick to apply."
Joining the Green Movement
"The Green Movement is here. Either you are going to be part of it or you're not," Douglas says. "We're demanding that a certain percent [of materials] is recycled content. We're trying to do our part."
This year, the company plans to continue working toward green products that are also affordable.
"We're looking at a couple of types of membranes and ways to make copper components green. That's something no one has been able to achieve," he says. "The materials are out there, but it takes work to go and find them and make them cost effective."
Other companies also are using recycled content. Hohmann & Barnard's Textro Flash Green is a 40-mil.-thick air and vapor barrier that contains 45 percent recycled material. The clear, self-adhering composite membrane self-seals around fastener and veneer anchor penetrations.
"The product becomes a green product because of the recycled component," Bupp says.
Hohmann & Barnard is making a conscious effort to produce products that are environmentally friendly, says Ron Hohmann Jr., company president.
"We're making a decision to go more green with our products, and some of our products were green to begin with," Hohmann says. "We find it is a win-win situation. It is an interesting challenge to continue to develop modes of incorporating green elements into our product line, and it is nice to know the demand is there and growing. Knowing that all of these changes throughout our industry are having a greater favorable impact on the environment is particularly rewarding."
The company plans to continue finding new ways to incorporate recycled materials into its products, he says. "Fortunately, green is here to stay."
|Last Updated on Monday, 16 February 2009 14:15|