The air barrier pre-installation meeting

Devil in the details

It is critical to review and verify contract documents and building envelope notes to the job-specific details provided by the air barrier subcontractor. Reviewing these details with adjacent contractors will confirm installation and sequencing; keeping a guide sheet of typical details to review and how connections of the air barrier are made will be an excellent resource for the meeting.

Typical job-specific details that should be reviewed are:

• base of wall(s);
• parapet or top of wall(s);
• openings (head, sill, and jamb) for each of the opening systems;
• penetrations, both before air barrier installation and after air barrier installation;
• soffits and overhangs;
• building and wall movement joints, including horizontal floor movement joints; and
• transitions to other building components.

Once shop drawings and other applicable submittals have been reviewed, the project complexities and building component clearances should be discussed along with the initial sequencing of the building components. Discussions on what will happen before and after air barrier installation and what, if any, additional instructions are needed for those installations are critical. For example, the cladding system might require additional flashing or detailing due to the installation procedures of that trade into or adjacent to the air barrier. Certain cladding components might need to be modified to accommodate the air barrier’s limitations, such as joints in the sheathing or even the type of anchor being used or its procedure of installation.

Knowing how the building is going to be detailed is essential for the next contractor in line in the installation process. For instance, the window contractor should know how the openings are being detailed and to expect an opening reduction due to material build-up, and how to correct the air barrier product if it gets damaged during window installation. There is a sizable thickness difference between flashing the opening with liquid or a peel and stick material. The build-up in the corners are vastly different, and contractors must be able to either accommodate these build-ups in the rough opening or have an opportunity to change the material to suit the overall installation of the building systems.

Penetration requirements

Penetrations are important to discuss; mechanical, electrical, plumbing, fire protection (MEP/FP) contractors should be aware of the requirements for their penetrations. Should a sleeve be installed and how is that sleeve detailed? What if there is not enough room on the exterior to install a sleeve that meets the air barrier manufacturer requirements for distance off the wall, such as detailing on to the sleeve a few inches? Is it possible to reverse the detailing of the sleeve, installing the membrane into the sleeve a few inches rather than on the exterior of the sleeve material?

Making sure the team understands compatible material to use as the sleeve is important to discuss early. The MEP-FP trades needs to know the penetrating material must be restrained from moving once detailed with the air barrier. How the penetrating object is installed on the interior is critical to the overall success of the installation. Additionally, the location of multiple penetrations must be discussed. The clear distance the penetrating object needs to be from other penetrating objects will depend on the type of air barrier and is different with each product and even installer.

Damaged substrate, what is considered damaged and the following procedure to correct the condition, should be defined. The air barrier might not be applicable under certain damaged conditions, such as damage to the facer or gypsum core material. The concrete might have too much honeycombing to be able to apply the air barrier, and the use of certain patch materials might not be ideal.

Building movement joints should be reviewed and understood. There should be an understanding about the air barrier plane versus the expansion joint material location. Typically, if there is a building movement joint, the joint will go through several different building components and involve many different trades and materials. Understanding where the air barrier plane is in relation to the materials being installed will take the entire team. For example, the air barrier will likely have a movement joint behind the veneer that will need to connect to the roofing movement joint. In this scenario, there must be a compatible transition membrane or compatible roofing component with the air barrier to the roofing membrane, and ample room for the installation of the cladding movement joint material in front of the air barrier joint. This detail will determine if the air barrier movement joint could be a compressible joint or must go into the movement joint to accommodate the cladding movement joint material.

Identify and review typical installation processes for the air barrier, such as span-ability of the material being installed, or how the peel and stick need to be applied. Most manufacturers have common installation practices for the air barrier type being installed. Having a list of updated procedures for the meeting will ensure the process or requirement does not get missed during this review. Typical overhead peel and stick type air barrier installation requirements, for example, are critical and might not have been detailed per manufacturer requirements.