Product Trends: Weather-Resistant Barriers

When it comes to trends in building-envelope products, no category has experienced quite as much innovation and improvement as WRBs. Many factors will affect selection of the correct WRB for your next job.

by Kyle Clapham

Widespread adoption of new building products takes a long time. Remodelers, home builders and home improvement pros tend to stick with tried-and-true methods and materials. Another factor slowing things down: Switching to new products also often requires code-writers to revise building codes. This process can take many years. And even after the code-writers get onboard, local inspectors often need time to get up to speed.

When it comes to residential building envelopes, the pace of new-product development, code updates and local knowledge have thankfully sped up significantly in recent years. This is particularly true in one of the most impactful building-envelope product categories—weather-resistant barriers or WRBs.

Benjamin Obdyke

Until the late 1960s, most remodelers and residential construction pros stuck with 15- or 30-pound asphalt felt paper to cover their exterior sheathing. To this day, some still use it. But plastic, paper and woven and non-woven housewrap materials have taken over. DuPont’s Tyvek brand is perhaps the most well-known of these. Typar is another. But there are literally dozens of brands out there on the market—some that can be private labeled by the remodeler or builder.

These housewrap solutions represent a huge swath of the market. They are installed as standard operating procedure at thousands of residential construction firms around the country. When fastened correctly (not with staples but with capped fasteners) and properly taped, these products are the new tried-and-true. They work well. But like most building products, housewraps are only as good as the person installing them. Training is required, especially around windows and doors, if isolated failures are to be completely avoided.

Remodeler Michael Anschel of OA Design-Build Architecture in Minneapolis, in his presentations on the topic of selecting WRBs, likes to make the point that exterior cladding has never been meant to keep out water completely. Cladding does much of the job of shedding water and moisture, but WRBs finish the job where cladding leaves off.

Tyvek is a leading brand in flat housewraps. It also offers advanced versions that drain quickly and keep substrates dry.

“The issue isn’t the ability for cladding to shed water. This is really where I think we’ve missed the boat when it comes to teaching and understanding how the building envelope is supposed to work,” Anschel explains in a recent interview with Qualified Remodeler. “Your siding or stucco or cladding—its job is to shed water quickly and to protect the building from sticks, rocks and sun. That’s it. The layer behind it, the WRB, our weather-resistant barrier, is a more sensitive system. It keeps the building dry. But, again, the cladding is not supposed to be weatherproof, and many of us make the mistake of trying to make siding weatherproof with extra caulking and trying to keep water from getting behind it.”

Typar is a leading brand in flat housewraps. It also offers advanced versions that drain quickly and keep substrates dry.

The sensitivity of weather-resistant barriers as part of a system is the reason why this category has seen a lot of new product innovation in recent years. As a result, WRBs have become more sophisticated in their ability to keep walls dry and sturdy. Today, there are entirely new WRB product types to consider when selecting building envelope products for your next job.

First, there are all-in-one OSB and WRB products. Perhaps the best known of this type is made by Huber Engineered Woods with its popular ZIP System. With this product, the weather barrier is integrated into the oriented strand board or OSB. Special acrylic tape is then tightly rolled out along the seam by the framing crew. Other companies have followed suit by launching similar all-in-one products, including Louisiana Pacific or LP. It makes a WRB sheathing product called WeatherLogic. Another entrant in this category is Georgia-Pacific, with its ForceField Air and Water Barrier System.

Within the all-in-one OSB-WRB category, a number of specialized supporting solutions have emerged. Huber makes a flexible stretch tape that can be pulled and manipulated to seal up tricky joints around windows and doors. In addition, ZIP System has proven to be a great solution in residential roofing applications.

Those are among areas for future growth, says Kristin Michael, growth marketing manager for Huber. In addition, the implementation of more stringent energy codes, namely California’s Title 24 regulation and its requirements for continuous insulation, as well as new standards for higher wind loads in coastal areas, will drive further growth in the years ahead.

Huber ZIP System is the leader in OSB-WRB combination sheathing products, which are used for walls and roof decks. Stretchable flashing tape has been a popular addition.

“The most recent California Title 24 Building Energy Efficiency Standards, the 2015 IECC and IRC all have prescriptive requirements calling for exterior continuous insulation that contractors are responding to,” Michael says. “Our ZIP System R-sheathing panels help achieve new energy requirements by streamlining water barrier, rigid air-barrier and continuous insulation into an easy-to-install panel and tape system.

“In the Southeast and Gulf Coast area of the country, states such as Alabama and Mississippi are requiring seam-sealed roofs, largely to meet new FORTIFIED Home certifications set by the Insurance Institute for Business & Home Safety (IBHS). Florida made significant changes to its statewide building code for 2021, which, among other steps, require sealing of the roof deck in a manner that is consistent with the IBHS FORTIFIED Roof designation. The state also made changes to the minimum required thickness of roof sheathing panels to address higher wind speeds.”

Advanced Housewraps

In recent years thicker, more technologically advanced housewrap products have emerged. Many now come engineered with a pattern of raised bumps or ridges. The bumps and ridges enable the product to better fulfill its longstanding job of evacuating any moisture that would otherwise get trapped behind a wall with less space for drainage. At the same time, the raised bumps also allow better airflow behind cladding. With better airflow, any moisture that might get through brick, stucco, vinyl, fiber cement or any other siding material will dry faster and not make its way through the barrier over time.

Huber ZIP System

Stopping moisture from lingering on the substrate, where it can begin to create rot, is the No. 1 job of a WRB. Many building products companies today offer these enhanced, thicker wraps as a very good but incremental step up from flat woven and non-woven wraps, without much requirement to retrain installers. A good example of this WRB product type is HydroGap from Benjamin Obdyke. DuPont’s Tyvek DrainWrap is another example, and there are many others from Henry by Carlisle, Cosella Dorken’s DELTA, TamlynWrap and Dow Weathermate Plus.

An even bigger step up in the advanced housewrap category is the emergence of a very thick WRB specifically designed to combat moisture issues associated with brick, masonry, thin stone, fiber cement and stucco cladding. These are 3D products that combine a wrap with a fabric filter, giving any trapped moisture extra space to wick away from the substrate. These are known as rainscreens. And they perform perfectly as advertised and work particularly well in areas with high amounts of wind, rain and wind-driven rain. Benjamin Obdyke is an innovator in this category with its Slicker MAX product. Others, like Henry by Carlisle with its WeatherSmart rainscreen, have also entered this category as well. Similar solutions are offered by DuPont, Dow and others.

Henry by Carlise offers a full line of WRBs. Pictured above is its rainscreen product WeatherSmart Drainable.

Also in the advanced wrap WRB product arena has been the emergence of what some believe is the most cost-effective and complete solution for the average residential contractor: self-adhering advanced housewraps. The perfect case-in-point is HydroGap SA from Benjamin Obdyke. It offers more space for drainage and airflow while also eliminating the need for fasteners and taping.

“Self-adhering will be the thing that everyone’s talking about for, I think, the next 20 years,” says remodeler Anschel, citing the introduction of an acrylic-based adhesive for Obdyke’s HydroGrap product specifically. Other self-adhered advanced housewraps have been introduced with much less forgiving, very sticky, butyl-based adhesives while acrylic adhesives can be repositioned before they are rolled and set.

Benjamin Obdyke pioneered the advanced housewrap category with its HydroGap product. The blue lines are raised ridges to facilitate draining and airflow behind cladding.

“I think the brilliance of their (Obdyke) move, by putting acrylic adhesive on the back of the HydroGap product, is that HydroGap is the first step up from flat wraps to wraps that have a 3D texture to it,” he adds. “With it we get fast-drying, fast drainage affixed with a solid acrylic, which means that it’s sticky, but not too sticky.”

A number of firms now offer an advanced, engineered thicker housewrap with premium drainage and drying capability that is self-adhering. Henry by Carlisle offers a product called Blueskin. And while this product is designed to be self-adhering, the adhesive is not continuous. There are gaps between the adhesive to allow for additional airflow.

Fluid or Liquid Applied

As is the case across the broader spectrum of building products, the biggest advancements are introduced in the commercial building market before similar products are adapted, branded and scaled for distribution in the residential construction market. This is the case with liquid-applied weather-resistant barriers.

They’ve been available for many years in hotels and office buildings. Only in the last 10 years have companies like Tremco and Prosoco brought them to homes. As a solution, they are very similar to the all-in-one OSB and WRB combination products but without the need for taping.

According to remodeler Anschel, liquid-applied WRBs as well as self-adhering advanced housewraps, might well be one of the best long-term WRB solutions. The only problem for fluid- and liquid-applied WRBs is the question of the installation. This is a big challenge because labor structure of the residential construction is not built for this type of task, which is akin to painting but is not exactly the same.

Georgia Pacific Dens Element and DensDefy are a WRB system of sheathing (ForceField) along with tapes and liquid-applied flashing.

“When you put a fluid-applied product in your carpenter’s hands, they do a bad job of it. They don’t think they should be doing that work,” Anschel explains. “They’re not painters. Or you can hire a painter, and they might say that they don’t do envelope-enclosure work. Lastly, you can go out and find an enclosure contractor, and then you’ve added a bunch of costs. Fluid-applied product is a great idea. In commercial building, it is routinely done. In residential, we’re just not sophisticated enough to make good use of it.”

In addition to Tremco’s Enviro-Dry liquid-applied WRB and Prosoco’s Cat 5 liquid-applied barrier, there are a number of liquid-applied flashing solutions. Included among these are Obdyke’s HydroFlash LA product, which has a distinctive blue color and comes in 20-inch tubes that can be used in caulk guns for convenient application. This product complements a line of HyrdoFlash tapes but is designed for difficult-to-seal geometries and spaces around windows doors and eaves. Huber’s ZIP System Liquid Flash is another example. And still more are available through DuPont, Henry Air-Block LF, Polyguard and Prosoco, as well as Carlise BarriBond.

Open-Joint Cladding

One of the biggest trends in residential design and construction has been the growth in cleaner, more modern forms and elevations. Open-joint cladding systems are commonplace on large commercial structures but are less often seen in residential settings. But that is changing with the growing trend toward modern design in homes. Open-joint cladding wall assemblies utilize a wide range of materials from wood to brick. In recent years even composite decking, with all its maintenance-free characteristics, has found a place in the residential cladding world.

In these systems, cladding still performs its essential tasks of blocking “sticks and rocks,” but it pushes more of the drainage load to the weather-resistant barrier beneath it. And because those WRBs are also visible, building product manufacturers have taken steps to introduce products that hold their color (mostly very dark) and resist negative impacts from ultraviolet radiation. UV protection is built into the products.

Benjamin Obdyke WRBs and batten products are equipped with UV protection for open-joint cladding.

There are several manufacturers in this space. Obdyke offers Invisiwrap and Batten UV products with ultraviolet light protection. In addition, there is Keene’s Driwall Rainscreen UV and Pro Clima’s Fronta Quattro all-black airtight WRB, which is designed specifically for open-joint applications.

One area not covered in this discussion about new and emerging WRBs is a class of reflective radiant barrier OSB sheathing products. Examples include LP’s Tech Shield and GPs Thermostat. These are primarily used in roof sheathing applications in warmer South and West climates. QR

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