December 2016: Trowel Tech Words: Dan KamysJeremy Douglas Mason contractors across the country face similar challenges when out in the field. With the help of Hohmann and Barnard’s director of technical services, Jeremy Douglas, Masonry delivers answers to some of your most technical, complicated questions. Q. I see a lot of masonry contractors installing fluid-applied air barrier systems. I have a couple of projects coming up where we were going to subcontract the barrier installation, but I think I’d like to see us move toward keeping that in-house. Do you have any advice to help us be successful? A. Do I ever. You’re right, more contractors are performing the air barrier work themselves, and I think this is a really good thing. The air barrier systems will usually interface with the flashing materials and veneer anchors, so I firmly believe the mason contractor should have as much control over that interface as he/she is comfortable with. Also, on CMU backup projects, you have the ultimate control over surface preparation for the barrier system, which is so critical to the successful application of a fluid-applied system. My advice is as follows: Understand what you are trying to achieve. A fluid-applied system is meant to be completely continuous across the entirety of the building at a specified thickness. This means the integrity of the backup wall must be solid, any holes or gaps must be filled or covered prior to application, and there must be no gaps or voids in your coverage of the substrate or where you wind up connecting to the roofing or below-grade waterproofing system. Rent the sprayer. Buy the sprayer if you like, but until you find one that works best for your company relative to size, output and cost, you can test drive spray equipment from your local supply yard or rental house. But whatever you do, use the spray equipment. Rolling the fluid-applied systems will usually lead to applications of less than the required dry-thickness, and ultimately a loss of continuity — not to mention the fact that you will be on site three or four times longer than if you were spraying Most manufacturers have certification classes for application of their fluid-applied systems. Be sure to take at least one. In some cases, it will be required on certain projects; but more importantly, the information you will gain will reinforce your ability to deliver a solid product. If you have the option, use fluid-applied transitional materials. Some air barrier systems have both traditional self-adhering tapes and fluid-applied transitions that you will apply with a caulking gun and a trowel. Provided it is self-supporting, a fluid-applied transition will be much faster to apply, adhere better to the substrate, and achieve continuity better than the self-adhered tapes. Be sure of what will be required of you at the terminations/transitions of the fluid-applied system. If the system is to terminate inside of a window opening, establish ahead of time how far into that opening you are required to go so you connect to the window unit as intended. It is unlikely you will connect the fluid-applied material directly to the roofing system or the below-grade waterproofing system, so plan out those transitions ahead of time and ensure that the transitions are without compatibility issues. Check penetrations for air leakage. Some barriers seal better than others, depending on their elasticity and dry-thickness. Any penetrations that are made to the barrier will need to be airtight, whether the air barrier acts as the sealing agent or you use a secondary tape, washer or other sealant to accomplish the same thing or to act as a redundancy. There will often be a third-party consultant who will advise on the air barrier installation throughout the process. It may sometimes seem as if they are being difficult or picky, but in the end they are trying to help you deliver the best installation possible. Try to work with them without taking their comments personally. Partner with your manufacturer. They are your best resource for technical information, troubleshooting, and problem solving and will be a necessary part of your process on every project. While not every issue you may come across is addressed here, this is a short list of the issues some air barrier installers struggle through when learning what these systems are all about. I absolutely support you and other contractors who want to better control the quality of the installed components of your wall systems. Best of luck to you. Jeremy Douglas, CSI, CCPR, has nearly 20 years of experience in the masonry industry working with veneer systems. He is director of architectural services for Hohmann & Barnard and can be reached at JeremyD@h-b.com.