So now that you've treated your rough opening with FastFlash and then installed your window, you are ready to install AirDam which is your interior air seal.
AirDam is a product based on STP chemistry, so it has a tenacious bond to FastFlash, which is also STP chemistry. When one of these products cures into the other, they become one monolithic membrane. Here you could see the interior joint of the Fas Flash rough opening against the vinyl window is all sealed with the AirDam.
Before installing the AirDam, if you have any shims for your window you want to make sure you turn them sideways to keep enough space for the backer rod and the AirDam sealant. Overall the installation is pretty simple you just want to gun it out and tool it around the entire perimeter of the window.
Featured in this video
Install Backer Rod
First, install backer rod in the annular space between the window and the rough opening.
Gun a bead of AirDam
Then you run a bead of AirDam across the entire space over the backer rod.
Tool the AirDam
Tool the AirDam around the entire area of the window, ensuring that you have a good bond to your window and a good bond to the FastFlash-covered rough opening. You want to make sure you have that hourglass shape to keep your sealant geometry in place.
With AirDam now in place, you have a full air barrier system and you are protected around the entire rough opening. Therefore, even in the case of a window-leak, you're protected from any water or air intrusion.
