Gaining Control of Masonry Wall Systems
Expand your bid package by looking for opportunities beyond brick and mortar
By Jeremy Douglas
Are you missing out on providing a critical component of masonry wall systems? The specific application of a building’s air barrier system seems often to remain a mystery to many mason contractors. Understanding wall systems’ purposes and their critical interfaces to adjacent materials reveals how simple they actually are. This article shines some light on masonry wall systems and helps eliminate any apprehension that may be keeping you from more work and, ultimately, more revenue.
First of all, let’s define what an air barrier is. Installed on the exterior face of the backup wall, an air barrier is a water resistive barrier that stops the movement of air. If designed to do so, it may also act as your vapor barrier. An air barrier is not waterproofing. This misnomer is used nearly everywhere. While an air barrier system may have similar physical properties or application methods of a waterproofing system, their duties are completely independent of one another. Think, instead, of your air barrier as air-proofing your wall system.
Why should you care? It is easy enough to simply focus on the areas of your expertise and experience and allow this portion of the work to be subbed out to another contractor. We tend to shy away from accepting added responsibilities in fear of additional liabilities, but in the case of air barrier systems, better understanding them may actually protect you. Forget this notion of repelling any legal responsibilities. As the mason contractor, you will undoubtedly be the first call made should a failure ever present itself anywhere within or adjacent to the wall structure – even when your work is sound. Retain control over as much of these wall systems as possible.
In most cases, interfacing some other product with the air barrier system is necessary – flashing materials, anchoring systems, z-girts, etc. A better knowledge of the barrier system can only be helpful toward a successful installation and a resulting wall system that will provide a longevity of service to match the design intent.
As an example, understanding air barrier systems will help to ensure there are limited, or no, compatibility issues between the barrier and a flashing material or sealant that will adhere to it. If a contractor’s focus is solely on laying brick into bed joints and ignoring the air barrier system, the system’s integrity will be compromised.
The field area of the air barrier is either a fluid applied or a self-adhering sheet material that runs continuously around the entirety of the building – all sides, connecting the barrier to the below-grade waterproofing and the roofing system – and isolating the openings. Either type of system will incorporate transition detailing for standard conditions like window or door openings and mechanical penetrations, or transitioning to other adjacent systems. The end result should be as close to a monolithic barrier as possible, with no breaches, to completely prevent the leakage of air into or out of the wall assembly.
Most mason contractors lacking experience in air barrier systems would be more comfortable covering a building in 36-inch-wide, self-adhering membrane than with a fluid applied coating. While self-adhering membranes can be effective as air barriers, they probably aren’t the most efficient for successful installation. Fluid applied systems tend to install quickly and make the verification of its continuity fairly simple. Ensuring there are no voids, gaps or fish-mouth gaps in the seams of the self-adhering sheet systems is a little more daunting – not impossible, but very difficult. In the project design phases, the use of fluid applied systems everywhere is typically best, except in the cases for which it doesn’t make sense to drag the fluid-applied system equipment to the site, or on block backup walls where only fluid-applied systems should be used.
The equipment for applying fluid-applied barrier systems can be the greatest obstacle to overcome. Many first-time fluid applied air barrier applicators look to utilizing paint rollers or brushes or submit self-adhering membranes as substitutions for the specified fluid products. From a labor perspective, this is a mistake. Roller application of a fluid applied membrane is incredibly time consuming as it will require multiple passes. And, it is almost impossible to accurately gauge the thickness of the coating during the application. Using a spray rig instead allows for a much faster application with better continuity of the field applied area. These spray set-ups come in many different sizes, can be either gasoline or electric powered configurations, and may have the option to run multiple hoses for quick coverage across the wall surface. Maintenance of these machines is usually minimal, provided that they are cleaned immediately after using and a deeper cleaning occasionally.
Small rigs, only a little larger than a pressure wash machine, are available and can easily be lifted into a truck bed. An initial investment for this equipment can be as little as a few thousand dollars, or rigs are available to rent.
Still apprehensive? Multiple opportunities exist for good training on masonry wall systems and their general applications. The Air Barrier Association of America (ABAA) offers installer certification programs and quality control certifications. ABAA certification is also available through the International Masonry Institute, which goes above and beyond ABAA requirements by demonstrating practical application and common field conditions. The air barrier product manufacturers will also often provide trainings that should show not only how their products are to be applied, but also how they want their product to be detailed in the field in various conditions. This training is invaluable, as that manufacturer will, undoubtedly, be a resource for you in the field for many projects in the future.
So, to recap a bit: Air barrier systems are critical components of wall systems. Their successful installation is inevitably tied to your portion of the work, whether you choose to install them or not. Many resources are available to installers to help ensure successful application, so don’t go it alone. The equipment to install these systems is a lot simpler than it seems. And don’t be afraid to broaden your scope of work. Become a contractor who specializes in the entirety of the building envelope. It leads to more work and, ultimately, more revenue.