: 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.
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 reliabilt-window-mull-kit-instructions
: 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 : Run a continuous bead of 100% silicone
: For a visual walkthrough, check out this guide on How to Mull Two Vinyl Windows Together . Window mullion installation #Lowes If you are using a , the process
: 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.
: 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.