How to Replace Window Muntins

Locate the tiny slots between the inner window frame and the ends of the muntins, or grids. Insert the tip of a pry bar into the gap to loosen the joint.

Grasp the muntin from the center with one hand and pull it outward until it bows. Pull the muntin down to release it from its upper window frame, and then pull it up to release it from its lower frame. If the muntin does not come out easily, remove the screws that attach it to the frame. Locate circular caps near the corners of the frame that cover the screws.

Use a utility knife to pry loose the cap to reveal the screws. Work carefully to avoid damaging the caps, since you will replace it later. Loosen and remove the screw from the muntin using a screwdriver. Set the muntin aside.

Grasp the center of the glass window with one hand and pull the inner window frame with the other. Carefully slide the glass out of the window and set it aside to keep it from cracking or breaking while you replace the muntin.

Assemble the new muntin if required according to the manufacturer’s directions. Secure the crossing bars with adhesive and allow it to cure for the time specified on its instructions.

Set the inner window frame next to the replacement muntin. Push the muntin away from the inner frame using your thumb. Do this at every point where the muntin connects to the frame. If required, secure the inner frame with screws after pushing it back into place. Replace the caps over the screw heads.