How to Install Glass Block Windows in Siding

Determine the width and height for the glass block wall such as 24 inches by 18 inches. Multiply 24 by 18 to determine the square footage of the window opening, which is 432 square inches.

Measure the width and height of a glass block with the tape measure. Make a note of the measurement such as 6 inches by 6 inches. Multiply 6 by 6 to get 36, which is the square footage of the glass block.

Divide 432 by 36 to get 12, which is the number of blocks that you will need for the glass block window.

Cut out a 28-by-19-inch section of siding with a reciprocating saw. Cut the sheathing of the wall to make the opening.

Cut the studs at the top and bottom of the window opening.

Place a 24-inch 2-by-4 at the top of the opening. Attach the board to the studs with nails by using a nail gun. Secure a second 24-inch 2-by-4 at the bottom of the opening.

Secure the perimeter channel to the bottom and sides of the window opening with screws with a power drill.

Set one of the glass blocks in place on the perimeter channel. Slide this block to the left. Place a second block on the perimeter channel. Slide this block to the right.

Apply mortar to the side of the next glass block with a trowel. Push the block into place on the right or left. You need a 1/4-inch mortar joint in between the blocks. Repeat this step to finish the first row.

Apply a bed or mortar 3/8 inch along the top of the first row. Place the next two blocks on the left and right of the first row. Apply mortar to the remaining blocks and set them in place.

Insert the expansion strip in between the top row and the 2-by-4 frame. Apply the sealant along the top of the top section of the perimeter channel. Set the channel in place in between the expansion strip and the 2-by-4 frame.

Attach siding trim around the glass block window on the outside wall. Attach the siding trim with nails using the nail gun.