DIY Window Slides Out of Track

Measure the height of the inside of the window along the interior side of the window sash using a tape measure. This is the length required for the trim molding.

Place a protractor on the sill of the window and measure the angle where the bottom of the sash adjoins the sill. This is the angle required for the bottom of each trim molding board.

Adjust the miter saw to the angle that you measured in Step 2. Lay each trim board on a work surface. Measure each trim board, and mark it to length using a tape measure and pencil.

Cut each trim board to length using the miter saw. Guide the saw through the wood in a steady motion, moving just fast enough to allow the blade to cut through the wood.

Fit the trim boards in place on each side of the window. Butt the back edge of each board against the window sash so it holds the board securely in place, yet allows it to move up and down. Hammer finish nails through the trim molding boards into the window frame every 4 to 6 inches so secure them in place.

Center a nail set over each nail head. Tap the nail set with a hammer to sink each nail head approximately 1/16 inch below the surface.

Fill each nail hole with wood putty using a putty knife. Allow the putty to dry for 24 hours. Sand the putty flush with the surface of the molding using a fine-grit sanding pad. Always sand with the grain of the wood.