Business Advice5 min

The Importance Of Vapor Permeability In Building Envelopes

Since 1898, the American Society for Testing and Materials (now called ASTM International) has developed technical standards for a wide variety of building materials. They test for things like burn resistance. For weather-resistant barriers (WRBs), ASTM has developed rigorous tests for water resistance and water penetration, plus an air barrier assembly test. But an equally important test is ASTM E96, which measures water vapor permeability over a 24-hour period.

Even after exterior cladding goes up, walls can get wet. Small amounts of moisture in the wall turn to gas (water vapor) that needs to escape. If walls can’t dry out thoroughly, the home is susceptible to mold and rot. 

The term vapor permeability (sometimes called “breathability”) refers to a material’s ability to let water vapor pass through it. ASTM E96 measures this in units called “perms” – and today’s building codes require WRBs to provide 5 perms or higher.

The Difference Between House Wrap and WRB

Since the 1960s, many builders have relied on plastic house wraps to achieve superior vapor permeability. But house wraps are applied after traditional sheathing is installed and approved by code officials. Then a crew has to return to wrap and tape the whole house.

In contrast, a product like new LP WeatherLogic™ Air & Water Barrier requires fewer steps. The sheathing and weather-protective layer are combined in a single panel that can be installed just like regular sheathing. The panel seams are then securely taped with an advanced acrylic tape that features one of today’s highest quality adhesives. And because the vapor-permeable overlay is permanently integrated into the panel, it won’t tear or blow away.

One of the best ways to get a tight building envelope is to use a structural panel like LP WeatherLogic barrier where the sheathing and vapor-permeable layer are tightly bonded during the manufacturing process. It’s a breakthrough that involves fewer steps and less waiting than using house wrap.

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Industry Trends5 min

Strong Demand for “Zero Energy Ready” Homes

Homebuyers are quickly realizing that there’s a new symbol of excellence in energy-efficient homebuilding: the Zero Energy Ready Home (ZERH) certification from the U.S. Department of Energy DOE. Currently only select builders meet the levels of excellence and quality required for ZERH certification – but their numbers are growing as homebuyers learn more about the program.

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Industry Trends5 min
Attracting More Millennial Homebuyers

About half of America’s would-be homebuyers are Millennials, but many have postponed their first home purchase because of sizeable student loan balances and lifestyle choices. However, there are clear signals that more Millennials are now ready and willing to take on a home mortgage. That’s especially true in metro areas that rank high on WalletHub’s “Fun Index,” U.S. News & World Report’s “Quality of Life” index, and Meyers Research’s “Housing Availability” metric. According to the real estate market analysis, there were seven metro areas where building permits grew by 15 percent or more last year, including Orlando, Houston and Minneapolis.

Industry Trends4 min
Some Common Misconceptions About Building Enclosures

It’s easy for small amounts of water to enter a home’s wall cavity, both during and after construction. When water evaporates it becomes a gas (water vapor) that needs to escape. If the walls can’t completely dry, a home is more likely to experience mold and rot.

Industry Trends5 min
What Architects Need to Know About Off-Site Construction

Why the “Field Verify” Approach Can’t Last Forever Last year LP invested $45 million in Entekra, one of the nation’s leading off-site homebuilders. As this type of construction gains popularity in the U.S., a number of architectural firms have asked Entekra to do presentations about how to successfully design for off-site homebuilding.