Seal the Deal: Proper Sealant Application is Critical to Project Success

By Craig Carson

The busier we are the faster time flies, and I can’t believe half the year is over.

Lately, I’ve seen an upswing in projects using prefabricated, cold-formed wall panels. The companies we work with are getting comfortable with preinstalling the windows and insulation before installing the panels.

Project Details

You may be familiar with the Populus project here in Denver. Designed by Studio Gang, the unique project incorporates glass fiber reinforced concrete (GFRC) fabricated panels hung on preinstalled metal stud wall panels. The GFRC product is a rainscreen for the building, meaning the prefabricated metal stud panel must incorporate the water and vapor barrier, and the windows are installed with their primary seal to the vapor barrier. Here is my soapbox moment. This work must be done correctly, because you only get one chance to get it right. Once hung, the GFRC is not coming off, and if you shortcut the design for the sealant joint, you may be living with a problem for a very long time.

Most of you will look at a project like this and agree that you need to be careful in the sealant application and execution, as well as the design. But do you see a correlation to more common rainscreen applications? Even though the GFRC gives this building a dramatic aesthetic, the core of the design is the same as a brick veneer, granite or metal panels. The primary seal is called “primary” because it’s the most important one. This is something we should pay better attention to in reviewing and thinking about perimeter details on the projects we bid, sell and manage.

In our trade, we need to be sure and understand where the primary seal is located (always to the water and air barrier). The architects detailing the windows may not recognize this. A decade ago or more it was common practice to install windows into the opening after the building veneers. That old way of thinking no longer works. You may assume that the exterior caulk bed is the primary bead. True, it is your first line of defense, but with rainscreen products, water will migrate and drain behind the first barrier and weep out. This casts greater importance on the seal at the vapor barrier and makes the exterior caulk joint a “beauty seal.”

Performance Testing

With many architects, building consultants and general contractors requiring performance testing on projects, we’re seeing these tests happen before the veneer is installed. This ensures the project is watertight before the veneer systems are applied or installed.

If you don’t understand why you would test at that point of construction, think of it like this: If you’ve fulfilled your responsibilities correctly, you will pass the test. All parties review it and everyone agrees the windows and installation works.

If a problem arises later you have the testing to back up your installation. It’s always cheaper to install the product correctly than come back and try to find the leaks and repair them.

Craig Carson is the vice president and general manager of 8G Solutions in Denver.

To view the laid-in version of this article in our digital edition, CLICK HERE.