December 2016: Trowel Tech

Jeremy Douglas

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.