Identify Wide Gaps and Problem with Direct Caulking

What happens here

Begin by identifying wide gaps around your window frame that require caulking. The speaker explains that if these large gaps are filled entirely with caulk, especially in areas subject to significant temperature fluctuations (like Idaho conditions mentioned in the video), the caulk will expand and contract, eventually pushing out and forming a large, unsightly bulge. The solution to prevent this is to use a backer rod.

Goal: Understand the necessity of using backer rod for wide caulk joints.