Mulling is the process of joining two or more windows together to fit into a single large opening. If you are using a , the process involves preparing the frames, applying sealant, and securing the units with structural connectors. ReliaBilt Window Mull Kit Installation Steps
: If your windows have nailing fins or J-channels on the sides being mulled, remove them using pliers or a utility knife to allow the frames to sit tightly together. reliabilt-window-mull-kit-instructions
: Lay the windows side-by-side on a flat surface. Use a utility knife to trim any excess vinyl "welds" or protruding edges from the corners where the windows will meet to ensure a flush fit. Mulling is the process of joining two or
: Align the windows and press the mullion strip (the H-shaped or snap-on piece from your kit) into the channel. You may need a rubber mallet to gently tap the strip into place until it snaps securely. : Lay the windows side-by-side on a flat surface
: You can find series-specific PDFs (e.g., Series 105 or 150) on the ReliaBilt Installation Support page .