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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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News & Stories6 min

How to Install Flashing Under Siding

Flashing is a key part of the LP® SmartSide® Trim & Siding installation process, helping to protect homes from the elements by preventing moisture intrusion. When you are installing lap siding, incorrectly installed flashing may lead to moisture issues that can affect other aspects of the home, in addition to the siding.

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Inspiration5 min
What Is the Difference Between Trim vs. Fascia?

When it comes to exterior cladding, homes require more than siding to protect them from the elements. Fascia and trim are two key elements that work together to create a protective barrier around the home, serving as a first line of defense along with siding.

Inspiration6 min
Top LP® SmartSide® Trim & Siding Virtual Resources to Help You Build Better

In today’s landscape of high competition and new ways of interacting with clients, easy-to-access virtual resources have become even more important. That’s why LP® SmartSide® Trim & Siding is committed to providing you the tools you need to keep up with the changing landscape.

News & Stories6 min
How LP® SmartSide® Trim & Siding Compares to Three Common Siding Options

If you are wondering how to choose siding material for your next project, we have outlined some key comparisons between LP® SmartSide® engineered wood siding and three other types of siding materials—fiber cement, vinyl and traditional wood.