Optimizing Multifamily Weather Barrier Design


A new class of fluid applied WB technology reinvents installation ease

Building a multifamily property to simultaneously meet code, profit goals, peer-property requirements, and tenant needs requires business flair and discipline. Today’s emphasis on affordable, wood-based mid-rise construction is a great illustration of that. For example, the Type III building type offers multifamily architects, developers, consultants, and builders a way to profitably develop urban in-fill locations with density, market appeal, and construction affordability.

Code demands

At the same time, evolving building and energy code standards, including the application of NFPA 285-tested wall assemblies, have placed even greater demands on architects and general contractors to deliver tight exterior wall assemblies. The weather barrier has emerged as a key component of that strategy.

Today’s weather barrier goes far beyond the capabilities of black paper. It must not only control airflow through the walls and hold out bulk water, but also allow interior moisture vapor to escape, and serve as a component of a NFPA 285-rated wall assembly, such as DuPont™ Tyvek® CommericalWrap®Tyvek® CommercialWrap® D, and Tyvek® Fluid Applied WB+™.

Challenging design

Building scientists, chemists, and engineers at DuPont—manufacturers of DuPont™ Tyvek® Building Envelope Solutions—have worked hard to optimize weather barrier performance and economics. Today’s mid-rise multifamily structures often present challenging combination of products to properly form a continuous, code-compliant weather barrier. What could DuPont weather barrier experts do to make the Tyvek® fluid applied product even more installer-friendly without sacrificing the product’s well-established performance?

Enhanced performance

Specifically, what could be done to enhance an already successful single-component product with even higher performance characteristics, such as:

  • Fast, “one-and-done” single coat application at just 25 mils (versus high-build, 90-mils products) with standard, off-the-shelf spray equipment
  • Long product open times, up to 90 minutes, before product curing
  • Nine months of UV resistance
  • Rain or snow: will not wash off the wall prior to curing (not water soluble)

The new and improved DuPont™ Tyvek® Fluid Applied WB+™ (weather barrier) is the result of that focused research and development. It’s not a different fluid applied weather barrier. The same advanced silyl-terminated polyether polymer technology shields the wall assembly now as before. DuPont™ Tyvek® Fluid Applied WB+™ is an improved weather barrier in every way that’s important to profit and performance-minded multifamily owners, developers, consultants, and builders.

Single-source peace of mind

Multifamily construction typically doesn’t have the large budgets of a commercial office building,” notes Tim Wilson, DuPont™ commercial marketing manager. “There may be certain areas of a project where it makes sense to save money with a traditional wrap. But there are other parts that require fluid applied. It pays for a property owner to work with a one-stop shop that offers both systems and the connections between the two.