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

Why does the U.S. lag behind in off-site construction?

What will the tipping point be for homebuilders to enthusiastically embrace off-site construction? When the labor force constricts even tighter and wages rise even more? Will it take more weather woes or neighborhood noise ordinances that further reduce the number of workable daylight hours? The number of progressive homebuilders using off-site construction methods are rising, but the industry in the U.S. as a whole continues to trail behind other countries.

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Exploring Building Envelope Innovations that Improve Indoor Air Quality

Achieving a tight building envelope is the new objective for many homebuilders and homeowners. A systems-wide approach combining thermal insulation techniques, various construction types, and high-performance water and vapor barriers can change a home’s energy efficiency.

Inspiration4 min
Dos and Don’ts of Installing Alternative-Use Sheds

Traditional sheds offer practical storage for items like tools, garden equipment and out-of-season toys. Today, sheds are becoming an extension of the homes’ living areas, offering versatile and multi-functional space. You’ve probably heard of them by several names, like She Sheds, Man Caves, Hobby Sheds, Backyard Bars and more.

News & Stories5 min
LP’s Commitment to Sustainability

The last Wednesday in October has been designated Sustainability Day throughout the world. Since the mid-1990s, LP has made great strides in sustainable forest management and manufacturing – and both Donna Kopecky, LP’s Public Policy & Sustainability Manager, and Kevin Warkentin, LP’s Business Environmental Health and Safety Manager for OSB and EWP, have been there every step of the way.