What Makes a High-Performance Housewrap?

No matter how tightly a building is constructed or what type of exterior cladding is chosen, moisture will always find its way into the building enclosure. That’s why synthetic housewraps (aka, weather resistive barriers/WRBs) are an essential component of a wall system, working in conjunction with other materials and thoughtful installation practices to protect the home’s structural components from moisture intrusion. But not all housewraps are created equal; high-performance housewraps offer a number of advantages that deliver even greater protection. 

What Factors Distinguish High-Performance Housewraps? 

All polymeric housewraps are designed to resist air and liquid water, while allowing some passage of water vapor (vapor open). Their strength and integrity is provided by a woven or non-woven fabric, water and air resistance are achieved by fiber-spun technology, and vapor breathability is achieved through fiber pore size, micro-porous films, or mechanical micro-perforations. 

High-performance polymeric housewraps offer these attributes while also incorporating features that can increase durability, provide enhanced moisture or air protection, lengthen allowable exposure times, and more.  

Here are a few things to look for when upgrading your building envelope with a high-performance housewrap. 

Woven vs. Non-Woven Housewraps 

Woven WRBs, made by weaving strands of plastic, are the cheapest in the polymeric category. These are generally waterproof—no water or vapor can pass through. Therefore, to achieve a perm rating, they need to be perforated with tiny holes poked in the membrane; these perforations compromise the air and water resistance because they create pathways that make them more susceptible to water infiltration under hydrostatic pressures and wind penetration, reducing the effectiveness of insulation and thus decreasing energy efficiency.  

Nonwoven WRBs, a high-performance housewrap alternative, are made by heat-bonding strands of plastic to create a uniform material with good strength and great flexibility. Most non-perforated products allow for sufficient vapor migration while providing excellent resistance to bulk water. 

Self-Adhered Housewrap 

Self-adhered polymeric housewrap is coated with factory-applied adhesive on the back side, which allows the product to stick to the wall. Unlike mechanically installed housewraps, self-adhered products deliver higher performance by self-sealing around fasteners, allowing the WRB to serve as an air control layer as well as a moisture control layer.  

There are additional performance distinctions within the self-adhered housewrap category, as vapor permeance can be achieved through either vapor-permeable advanced acrylic technology or a discontinuous coating of butyl adhesive. 

Continuous adhesive achieves its permeability through the advanced technology of the acrylic adhesive that has a consistent thickness on the back of the self-adhered WRB. This results in higher performance. 

Discontinuous adhesive relies on the gaps in between the adhesive for its permeability because the adhesive is vapor closed. The application of adhesive for these products mimics “Silly String,” as it randomly applies the adhesive to the back of the product. Because its adhesive coverage is not consistent throughout, it may not adhere to the wall as long and may not self-seal around fasteners in all places. 

Durability 

A housewrap must be able to withstand the handling and application process without compromising its water-resistance performance. The tear resistance, or tensile strength, of the product is the best available indicator of whether or not a housewrap might be damaged.  

HydroGap and HydroGap SA drainable high-performance housewraps feature tri-laminate construction for added durability and a reinforcement scrim in the adhesive that provides greater tensile strength.  

Long-Term UV Exposure 

Prolonged UV exposure can degrade some housewraps, but there are a number of high-performance housewraps that allow for longer exposure times, increasing jobsite flexibility. InvisiWrap SA, for example, allows for up to 12 months of UV exposure, making it an ideal solution for long project lead-times and open-joint cladding.  

Drainage 

Drainage is widely accepted as one of the most effective measures for reducing moisture damage due to rain penetration. According to a study by John Straube and Jonathan Smegal of Building Science Corporation, a 1mm drainage gap “will drain water at a rate considerably greater than rainwater is expected to penetrate behind cladding even in extreme conditions.”  

High-performance housewraps may feature an integrated gap and drainage plane. For example, HydroGap and HydroGap SA have patented 1mm spacers that create a true drainage space with 96% drainage efficiency and will remove water 2x faster than flat housewraps.  

Surfactant Resistance 

Surfactants, or surface-active agents, lower a liquid’s surface tension, enabling it to seep more deeply into materials. In construction, they are naturally present in substances like cedar, stucco, and stone mixtures, as well as in cleaning solutions used for power washing. When water infiltrates a building system, it can carry these surfactants, allowing them to move further into wall assemblies. Over time, this process can diminish the effectiveness of housewraps,  allowing moisture to reach the underlying sheathing and other layers. High-performance housewraps are specifically designed with coatings that resist surfactants. All Benjamin Obdyke’s housewraps are surfactant resistant. Using a high-performance drainable housewrap can also provide a space to carry water away, mitigating surfactant-induced damage. 

High-Performance Housewraps Create High-Performance Homes 

Specifying a housewrap is an important component of a robust building envelope—but the housewrap you choose matters. Opting for a high-performance housewrap that provides non-woven construction, increased durability, self-adhered acrylic technology, drainability, longer UV exposure times, or a combination of these features can help further protect the wall system from moisture and air infiltration. 

Learn more about how to select the right housewrap by downloading our white paper.