Traveling around the country, the most common reaction I get from a mason contractor when I bring up the subject of installing their own air barriers is “I don’t understand them well enough” or “Too much liability…I am just not interested”. I tend to challenge back by asking if they understood laying masonry when they first started?? I will normally follow that up with another question “Isn’t there plenty of liability in what you are already doing…laying masonry….installing reinforcement/anchors (potentially poking thousands of holes through the air barrier)…installing thru-wall flashing systems? As with anything else in life…fear of the unknown is a powerful factor in people’s decisions, and as always Knowledge is King and it is no different with air barriers. Today there are plenty of sources out there ready and willing to share their knowledge and experiences with regards to air barriers. In most wall systems the air barrier comes in contact with all the other products that you currently install and are responsible for! Most manufacturers have personnel that will “hold your hand” on a project as you get started in this business and I have also seen a movement by masonry industry organizations to encourage and train mason contractors how to properly install air barriers. Slowly more and more masons have jumped into the air barrier arena typically with very good success. I have even seen some architects including the air barrier in the Masonry division, especially on projects with a CMU back-up and brick or stone veneer.
There are many facets to the air barrier business and most masons that have taken the plunge tell me that they are surprised at the ease of installing air barriers….after training, certification, and going through the learning curve. It has been my experience that learning and getting comfortable with spraying fluid-applied barriers is the biggest challenge and typically some level of comfort can be achieved within the first day or two, and detailing relates right back to the flashing training and expertise that they have already acquired. In fact, a number of mason contractors that I know now have a separate division with specially trained installers to do the air barriers, and some others have even started quoting barrier installations to their competitors! I always encourage contractors venturing into a new area of business to be very selective with their first couple projects looking for smaller and/or simpler projects to start out, and when considering installing air barriers to think of the wall assembly as a roof, and if you could turn the wall horizontal and ask themselves “Is this wall watertight?” Typically if the wall was placed in the horizontal plane and remain watertight, most likely in the vertical plane that same wall would be airtight. The common themes I hear back after the first few projects are “This isn’t as difficult as I thought it would be” or “I love having total control of my project”.
Obviously, air barriers are a whole different world from laying masonry but let’s face it…the air barrier is here to stay and is an integral part of a masonry wall assembly. There are quite a few things to think about with regards to air barriers and masonry walls, and here are just a few:
- Understand compatibility and adhesion between barriers, flashings and anchor systems.
- Surface preparation for air barriers is critical, and proper surface prep can actually save time during application.
- Improper preparation of back-up walls by others such as large gaps in sheathing and over-driven screws is NOT your responsibility.
- Knowing detailing application and the pros and cons of sheet or liquid detailing materials and detailing before or after the barrier application.
- Make sure of the proper tie-ins to the roof and below grade waterproofing.
- Make sure of dissimilar material interface detailing methods. (differing movement characteristics of various materials)
- Basic understanding of sealants/mastics since they will come in contact with the barrier system.
- Think about the anchor system used with the barrier and will those two products function well together?
- Plan out your door, window and pipe penetration detailing…use basic flashing concepts.
- Control and expansion joints need to be addressed.
- General knowledge of the difference between breathable and non-breathable barrier products and where one might be more applicable. (Good to know)
- Spray using “Crosshatch” method with both vertical and horizontal spray paths to ensure complete encapsulation of pipe and other penetrations, plus coverage of masonry wire and veneer anchors with no shadowing.
- Learn how to monitor mil thickness of fluid-applied barrier materials.
- Will the specified thru-wall flashing system function with the barrier?
- Weather conditions such as temperature and humidity will impact air barrier installations, curing times, etc.
As the exterior building envelope continues to evolve into an extremely important aspect of any structure, general contractors are looking to work with fewer sub-contractors to minimize confusion between the exact scopes of work of various subs. And they would much prefer to work with an all encompassing envelope contractor that has the knowledge and understanding of all the complexities of multiple wall component products and how they are properly applied and interface with one another. On a number of masonry projects that I have been involved with, the GC or CM has pushed the air barrier into the masonry contractors scope of work. Penetrations through the exterior envelope after the air barrier contractor has completed his installation (and we all know they occur), become much easier to deal with since typically the mason contractor will still be on the job and can easily make the proper repairs.
It has become time to embrace this new world part of our industry that impacts your historical scope of work. Don’t just be a mason contractor, broaden your reach and become that building envelope specialist that many general contractors and construction managers are looking for. It starts with a commitment to making this part of your companies expertise, and that can be accomplished with knowledge and training. The Air Barrier Association of America (ABAA) continually provides training and certification courses with both classroom and hands-on segments. Most manufacturers will also provide training and certification classes geared more to their specific products and applications. With many manufacturers in the air barrier business, take advantage of those trusted resources for application techniques, detailing options, pricing and estimating support.
Words: Chris Bupp
Photos: Chris Bupp