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
: Apply additional silicone sealant to the top and bottom of the mull joint, filling any voids. If your kit includes a drip cap or mull bridge , install and seal these over the top and bottom exterior joints. Helpful Resources reliabilt-window-mull-kit-instructions
: 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. Mulling is the process of joining two or
: Open the window sashes to access the factory pre-drilled holes or specific reinforcement areas. Drive the provided screws through one frame into the other (staggering them if necessary) to pull the units tightly together. If your kit includes a drip cap or
: Run a continuous bead of 100% silicone sealant along the entire length of the channel where the windows will connect. This step is critical for preventing air and water leaks.
: You can find series-specific PDFs (e.g., Series 105 or 150) on the ReliaBilt Installation Support page .