What Builders Need to Know About WRBs

The Case for Choosing a Best-in-Class WRB

Water-Resistive Barriers (WRBs) play a critical role in keeping unwanted moisture out of the home and clean, conditioned air inside. They drain water away from the building envelope, protecting the insulation and sheathing. Many WRBs can also be installed as an air barrier to form a continuous airtight seal around the home. 

Without a good water-resistive barrier (WRB), wind-driven rain can push water through the cladding, damaging insulation, rotting sheathing, and causing mold to proliferate within the building envelope, potentially affecting resident health. Meanwhile, builders and homeowners may face costly remediation and potential litigation.

Continual rain, snow, and wind coupled with water’s ability to seep through the tiniest crevices make moisture intrusion the most common source of damage and litigation. An estimated 80-90% of construction defect lawsuits involve water intrusion with most cases originating in building envelope failures.

Building envelope products, particularly WRBs, can protect against moisture’s insidious threat, but they are not invincible. Product failures and installation errors expose homeowners to moisture and builders to legal and reputational risks. That’s why it’s important to select a proven WRB backed by a long-term warranty like Henry’s 1-2-3 Moisture Control System.  

Builders should avoid the temptation to lump all WRBs together. Instead, they should understand the different types of WRBs and the strengths and vulnerabilities of each. They should also prioritize installation support and expertise to avoid common pitfalls. 

This blog evaluates different WRBs options to help builders make informed decisions and get the support they need to protect themselves and homeowners.

Understand the Role of WRBs in the Building Envelope

As the second line of defense in a building envelope, WRBs prevent water which may seep through the cladding from damaging the sheathing and underlying structure. 

A WRB’s primary function is to resist bulk water intrusion, such as wind-driven rain, while draining residual moisture away from the wall assembly. The best WRBs also incorporate an air barrier while remaining vapor permeable, allowing wall assemblies to dry and in turn reduce the risk of mold growth. 

The industry considers the WRBs an essential part of the building envelope, so much so that the International Code Council (ICC) added a WRB requirement to the International Residential Code (IRC).

“The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior cladding as required by Section R703.2 and a means of draining to the exterior water that penetrates the exterior cladding.” [engineerfix.com], [2024 IRC Section R703.1.1]

Effectively keeping water out and away from wall assemblies requires a meticulous process of selecting and installing the building envelope products and includes:  

• A durable WRB that can resist damage that can occur during construction
• Installation expertise and monitoring
• Tight integration with window and door flashing
• Chemical and material compatibility between adjacent products
• Careful transitions between existing and new materials during remodels

Installing a WRB can be challenging, and the error margin is high. Each step introduces opportunities for mistakes that can compromise the entire system. For example, when builders use fasteners to attach a WRB, they create penetration points that can become pathways for water intrusion. 

Watch Blueskin® VP100 Stand Up to Water, Air, and Fasteners

In this Build Show demo, Matt Risinger compares a standard housewrap with the Henry® Blueskin® VP100 self‑adhering weather‑resistive barrier (WRB), exposing both to water, air, and fastener penetrations. See what happens when he pours an entire bottle of red Gatorade directly onto the nail holes.

WRB Pioneers: Asphalt Felt and Building Paper

Not All WRBs Are Created Equal

Builders have installed WRBs for decades with varying levels of success. Fortunately, WRBs have progressed significantly since the asphalt felt and building paper systems introduced more than 100 years ago. When properly layered and installed, the pioneering WRBs helped shed water away from wall assemblies but proved relatively fragile. They were easily damaged during installation and tended to wrinkle and absorb water over time. Asphalt-based WRBs do not have the UV resistance of their modern counterparts and need to be covered by the cladding quickly, which is not ideal when trade sequencing and other factors can sometimes extend the WRB exposure period many months. They also lacked an integrated air barrier, which can contribute to a buildup of condensation in the envelope.

Contemporary WRBs: Mechanically Attached and Fluid Applied Options

Mechanically attached and fluid-applied housewraps eventually replaced their more delicate predecessors, offering better durability and vapor permeability. 

Mechanically attached WRBs

Typically manufactured from woven or spunbonded polyolefins (plastics like polyethylene or polypropylene), mechanically attached wraps are installed over exterior sheathing and secured using staples, nails, or cap fasteners. To perform effectively, they require properly lapped courses, taped seams, window integration, flashing details, and consistent sequencing. Small installation inconsistencies or errors can create discontinuities that affect water and air barrier continuity and can lead to costly repairs or worse. The following common conditions can lead to potential points of leaks and failures.

• Improper fastener installation: Overdriven staples or nails, angled fasteners, torn material around attachment points, or missed framing members can compromise the WRB surface.
• Wind loading and billowing: Repeated movement from wind pressure may enlarge fastener holes, stress seams, or create wear points that reduce water and air control performance.
• Water migration around penetrations: Wind-driven rain, pressure differentials, and poor detailing make penetrations near seams, openings, or transitions particularly vulnerable.
• Installation damage during construction: Housewraps can be punctured, torn, or pulled loose by tools, handling, and weather exposure. 

Fluid-Applied WRBs

Fluid-applied WRBs are sprayed or rolled onto wall assemblies to create a monolithic, seamless membrane. These products conform well to irregular substrates and can simplify detailing around penetrations and transitions. However, they can still be vulnerable to installation errors, damage, and failure due to:

• Film Thickness Variability: Thin spots, overapplication, and uneven coverage can affect protection, durability, and installation efficiency.
• Weather & Environmental Sensitivity: Temperature, humidity, substrate moisture, and weather fluctuations can hinder curing and application efficiency.  
• Cure Time & Sequencing Challenges: Many fluid-applied systems require extended cure times that can cause project delays.  

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How Self-Adhered WRBs Reduce Risks

Self-adhered systems, such as Blueskin® VP100, address many of the vulnerabilities associated with mechanically attached and fluid-applied WRBs. Blueskin VP100 fully bonds to the substrate rather than relying on staples, cap fasteners, tapes, and perfect sequencing. In addition, the self-adhered WRB can provide tighter integration around transitions, openings, and penetrations where enclosure failures frequently originate.

Peel-and-stick water-resistive barriers … are growing in popularity thanks to some pretty exceptional benefits. They are rolled out like a housewrap, so the seams lap for drainage, and the adhesive creates a gasket around siding fasteners. Because they fully adhere to the sheathing, they share the air-sealing potential of a panel product.—Fine Homebuilding

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How Blueskin® VP100 Addresses Common WRB Challenges

 

The Blueskin VP100 Advantage

Blueskin VP100 helps builders overcome common limitations associated with both mechanically attached and fluid-applied WRBs by combining self-adhered installation, factory-controlled membrane consistency, immediate continuity, and predictable application.

Designed for wood-framed residential and multifamily construction, Blueskin VP100 helps protect wall assemblies from water intrusion, moisture migration, and uncontrolled airflow in a single integrated layer. Rather than depending on mechanical fastening patterns or field-applied coating consistency, Blueskin® VP100 combines an engineered membrane with patented permeable adhesive technology to create a fully adhered, vapor-permeable water-resistive air barrier. Since it fully adheres to sheathing, Blueskin VP100 creates a continuous weather protection layer without billowing.

Blueskin VP100’s sealing technology creates an air and water barrier that is designed to outperform traditional WRBs by helping reduce the movement of air and moisture through wall assemblies, which can contribute to lower heating, ventilation, and air conditioning (HVAC) energy costs. In a side-by-side blower door comparison conducted with a residential builder, Blueskin VP100 demonstrated measurable airtightness improvements compared with a leading asphalt felt wrap approach.

See how easy it is to install Blueskin® VP100 and how quickly it creates a continuous air and vapor barrier. Watch a contractor install Blueskin VP100

Proven 95% Drainage Efficiency

Blueskin VP100 provides continuous protection behind the cladding while still allowing walls to breathe. The next-generation WRB also delivers 95%+ drainage efficiency, helping move water away from the wall assembly while maintaining vapor permeability to allow walls to dry.  

Substantial Energy Savings

By helping reduce uncontrolled airflow, Blueskin VP100 can help improve energy efficiency, HVAC performance, and the air and water tightness of the building envelope. In even the most well insulated homes, as much as 40% of the energy used to condition the interior spaces can be lost to uncontrolled airflow. Unlike traditional building wraps that resist only water and moisture, Blueskin® VP100 also prevents energy-wasting air leakage, enabling significant energy savings.

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Blueskin VP100 Key Benefits

• Self-Sealing Around Nails and Fasteners: The membrane’s adhesive technology helps seal around fasteners and penetrations, mitigating a common failure point. Self-adhered installation also helps eliminate gaps and loose areas.
• Air Sealing: It reduces uncontrolled airflow, improves energy efficiency and HVAC performance, and can contribute up to 50% in energy savings.*
• High Drainage Efficiency with Breathable Performance Blueskin VP100 delivers 95%+ drainage efficiency to help move water away from the wall assembly while maintaining vapor permeability that allows walls to dry. Vapor permeability that supports drying.
• Improves air quality: By preventing moisture intrusion and condensation from developing, VP100 reduces the potential for mold proliferation.
• Easy installation: The peel-and-stick system simplifies the installation process and eliminates the need to manually install fasteners.
• Long-term protection: Backed by a 15-year warranty when installed as part of 1-2-3 Moisture Control System.

 * Based on Hot2000 Simulation, Denver, CO; for a two-story, 2,000 sq. ft. home. Based on energy modeling.

Ongoing Partnership and Warranty

Henry experts work closely with architects, owners, and contractors to identify building envelope solutions and select products for each project from among compliant, award-winning products proven to deliver on design intent. Support starts with the initial design and continues with ongoing technical guidance.

When builders implement Blueskin VP100 as part of Henry’s 1-2-3 Moisture Control System, they can qualify for a comprehensive 15-year warranty. The Moisture Control System also includes Henry flashing and sealants, which are tested and proven to work together seamlessly. In the unlikely event of a leak caused by product failure, repairs are covered for both materials and labor through a single point of contact.

Construction schedules are demanding. Builders value systems that install predictably and withstand field conditions. VP100’s peel-and-stick application can simplify installation compared with mechanically fastened systems while reducing many of the environmental and curing variables associated with fluid-applied products.