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Air Barriers Rising
One hundred fifty shares of Microsoft stock, bought at $21 each during the company’s initial public offering March 13, 1986, today is worth about $1,080,000.
Today, air barriers for cavity wall construction offer a similar opportunity for masonry professionals.
Even as you read this, the fledgling air barrier industry is lifting off, just as Microsoft did 20 years ago. You already know how growing public awareness of the value of computers and software made Microsoft a huge success story and Bill Gates the world’s richest man.
The construction industry, including organizations like the Brick Institute of America, and the International Masonry Institute, has already begun to grasp the importance of air barriers. As the market learns that air barriers can prevent mold in walls, and take huge chunks out of a building’s heating and cooling costs, demand will grow.
Just like Microsoft, 1986.
But there’s one big difference.
No state code ever mandated the use of Microsoft products. Air barriers are already required by codes in Massachusetts, Michigan and Wisconsin. They’re being considered by authorities in 21 other states, according to the Air Barrier Association of America. ABAA predicts a national air barrier code in the next five years.
When you add requirement to demand, the potential is unlimited for masonry professionals whose expertise expands to include air barriers.
Why do we need air barriers?
We need air barriers because warm, moist air has a bad habit of leaking into cool wall assemblies and condensing. The resulting liquid water causes conditions for mold, and mold litigation. It also causes rust and other kinds of wall-component deterioration.
To find out how much water actually gets in walls that way, Disney Development Company hired engineering consultants CH2MHill, Englewood, Colo., to study the issue.
They found that a crack 1 inch long and 1/16th of an inch wide, in a 500 square foot wall, let in the water vapor equivalent of 80 ounces of liquid water per day via air leakage. That adds up to 228 gallons of water yearly—liquid, not vapor. That’s plenty for rust and mold.
We need air barriers because, as a 2005 study by the National Institute of Standards and Technology showed, air barriers can slice a building’s natural gas costs by over 40 percent and electrical costs by over 25 percent.
Those are savings that can’t be ignored as the days of cheap energy retreat ever further into the past.
How do air barriers work?
Air barriers cover all openings in structural walls. They are simply barriers to air. In hot weather, warm moist air tries to get in walls through weepholes, failed mortar joints and other openings in the masonry veneer.
But if the structural sheathing or CMU backup is covered with an air barrier—continuously and seamlessly—that air just can’t go any further. It can’t get in through seams, joints and connections of the structural wall to condense in the cooler recesses of the wall assembly.
In cold weather, warm moist air from living spaces leaks into the wall assembly via electrical or plumbing penetrations, or any other openings. If there is a pathway to the great outdoors via those seams, joints and connections in the structural wall, you’ve got an air stream of energy dollars blowing out of the building.
But again, if that structural wall is covered with a seamless, continuous air barrier, the escaping air is stopped. No stream; no loss. Big savings.
Knowing the difference between the products that do this effectively and the products that don’t is going to be like the difference between buying early stock in Microsoft and early stock in InfoCom. (Remember InfoCom?)
4 checkpoints for effective air barriers
There are lots of products sold for this purpose. They come in liquids and solids, sheets and rolls. They are water-based, solvent-based and asphaltic. They spray on, staple on, or stick on like adhesive-backed wall paper.
But no matter what they look or smell like, or how they install, air barriers MUST meet four basic checkpoints to be effective.
These “Big 4” checkpoints are:
• Continuous and seamless
• Structural
• Durable
• Vapor permeable
A brief look at each checkpoint shows they really are just common sense.
Continuous and seamless
To stop air from going through the structural wall, the air barrier must cover everything. All the nooks, crannies, cracks and transitions of the wall assembly must be covered, 100 percent, with no gaps, holes or seams.
That’s common sense, because if there’s a hole, air will get through.
Structural
The air barrier must stick so tight to the structural wall that it takes on the strength of the wall itself. That means the wall must fail before the air barrier will detach. That’s common sense. For example, if during construction the wind tears part of the air barrier free, and it isn’t repaired before the veneer goes up, air will get through.
Durable
The air barrier must resist weathering for up to six months unprotected in case of construction delays. That’s common sense, because if weathering makes the air barrier brittle and cracked, air will get through.
Vapor permeable
The air barrier must be vapor-permeable or “breathable.” If water or water vapor does get into the wall assembly—from a leaky pipe, for instance—it has to be able to evaporate out through the air barrier. If it’s trapped by a vapor-impermeable barrier, the water will stay in the wall to help breed mold.
That’s common sense because anything that can’t dry out gets moldy.
Always insist on seeing technical data that verifies the products under consideration meet these “Big 4” checkpoints. You take a huge risk if you settle for less.
Other considerations
There are other common sense considerations in choosing air barriers. For instance, is the product water-based or solvent-based? A water-based product may be less likely to run afoul of state environmental regulations. And it may be easier and safer to apply.
Ease of application is also common-sense. A cheap product that’s hard and time-consuming to apply does no one any favors. The more complex the installation, the greater the chance it will be incorrectly installed.
As you know, labor is the most expensive part of any construction project. So easier means more margin.
Knowledge is power
If you followed software companies in the early 1980s, you might have noted a small private firm called Microsoft was doubling and tripling its earnings every year. That knowledge would have helped you single Microsoft out from many other software companies now forgotten.
In construction, air barriers are on the rise. But just like with computer products in the 80s, you have to look closely and use common sense to identify the right air barrier products.
If you know and act on what works and what doesn’t, in 20 years that could mean the difference between sailing your own yacht or working for someone who is sailing his or hers.
Just ask the people who bought Microsoft in 1986.
Visit the training page at www.prosoco.com for in-depth information about air barriers, including PROSOCO’s own PROSOCO R-GUARD™, fluid-applied air and water-resistive barrier for masonry cavity wall construction.
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