How to Install the Trim of a Victorian Era Block Window

Place a tape measure along the front edge of the jamb on the window frame and measure 1/8 inch from the inside of the window. Draw a mark using a pencil and then make additional marks around the perimeter of the window every 6 to 8 inches. Connect the lines using a straight edge and pencil.

Measure the inside width of the window opening from the left to the right jamb. Add ¼ inch to the measurement and then add the width of the two pieces of trim molding that will reside on either side of the window.

Lay a window stool, which is a long flat board, on a table and draw a mark designating the total measurement you calculated. Cut the stool using a hand saw.

Hold the stool up to the base of the window and center it. Draw lines on the board to indicate where the openings of the window end and then turn the lines at a 90-degree angle toward the end of boards. The result is that you will have two 90-degree-angle marks at either end of the board that create notches to cut out.

Don safety glasses and cut out each notch using a jig saw.

Apply a 1/4-inch-wide strip of wood glue to the entire back edge of the stool and press it into place on the window frame.

Measure the left and right sides of the window from the top of the stool to the pencil line on the top portion of the window jamb. Cut two strips of straight trim to the same size and attach them using wood glue and 4d finishing nails spaced at 6- to 8-inch intervals.

Turn the two corner blocks upside down and apply wood glue around the perimeter of each. Install each corner block at the top of the left and right trim, centering it over each.

Measure the distance between the two blocks and cut another straight piece of trim to the same size. Apply wood glue to the back of it and secure it in between the two blocks using finishing nails.

Wait until the wood glue dries completely and apply silicone caulk along the seams of the blocks and straight pieces to seal the gaps.