Glass-Block windows are used in area where they are not usually opened. A popular choice is Glass-Block basement windows or false windows between rooms. These windows add an element of design style while functioning to block heat, cold and they obstruct the view of anyone looking in or out. Glass-Blocks for both windows and wall are available in a variety of colors and shapes and sizes. Installing a Glass-Block window is a fairly easy do it yourself home improvement project, it does not require any special masonry skills or much equipment. The only difficulty you may run into is Glass-Blocks are available in specific sizes and are not made to be cut therefore the existing window opening would need to be modified to made it larger or smaller. Even modifying the opening is not overly difficult and should not stop you from installing Glass-Block windows.

Remove the existing lens and window-frame.

Measure your rough opening from side to side and top to bottom, note the measurements. A rough opening is the area that has not been framed out.



Method 1


Buy a metal grid system. A metal grid system is a framework of squares that the Glass-Blocks fit into.

Simply install the frame of the grid into your rough window opening. Use masonry screws to screw the framework in.

Place the blocks into the ready made partitions. It is a snap and lock type system. Once the Glass-Blocks are snapped and locked in place, you are done. This is best used for small windows and decorative interior windows.

Method 2:


Screw a Glass-Block frame into the rough opening. This type of frame does not have partitions to snap and lock Glass-Blocks in place.

Place the first row of Glass-Block into the bottom of the frame, then the second row and so on.

Use spacers in between Glass-Blocks to maintain an equal and uniform distance between the blocks.

After all blocks are in place, caulk the joints. Use a silicone caulk and a caulking gun.

Method 3:


Build the Glass-Block wall on the ground using mortar between the blocks.

Begin with your first course, use a trowel and put about 1/2 an inch of mortar on the side of the first Glass-Block, butt the second block up against the first block. Use a level to make sure the blocks are even and level. Continue for the entire first row. On the second row add mortar to the sides and bottom of the Glass-Block. Continue until the window is built.

Allow the mortar to dry completely.

Have someone help you from the inside.

Apply a thick layer of mortar on all edges of the rough opening.

Wedge the window into the opening, make any adjustments for leveling while the mortar is wet. If you need to lift one side, use wood shims under the side that needs to be lifted.

Allow the mortar to dry completely.

Mix more mortar and use a trowel to mortar around the outside of the window, slope the mortar away from the window. Repeat on the inside of the house.