How To Install A Glass Block Basement Window

Posted on: 30 November 2016

Glass block is a great window material choice, as it allows plenty of light into your basement, while preventing anyone from seeing in. It's also durable and easy to maintain. You can install this type of window yourself if you're a little handy using glass block panels. See below for instructions on how to install a glass block window for your basement.

Tools For The Job:

  • Glass block panel (in the size of your window)
  • Hammer
  • Pry bar
  • Caulk and caulk gun
  • Level
  • Ladder
  • Tape Measure
  • Mortar
  • Trowel
  • Shims
  • Protective eye wear and gloves


  1. Begin by taking out the old window itself including the casing, jamb and sill Use your pry bar to get the jamb all the way out, including the bottom, sides and top jamb. If need be, you can use a circular saw or reciprocating saw to cut through it to help get it out, but be sure not to cut too far, or you can ruin your blade by hitting the concrete. If your window has a curb holding the sill in, remove both of these as well. In this case, you may need to use a chisel. Be sure to wear protective eye wear before chiseling.
  2. Once you have a clear area to work with, you can begin installing the glass block panel. To do this, you'll first need to screw in a small piece of wood between the joists at the top of the window opening to help prevent the glass block panel from falling through the opening.
  3. After the piece of wood is in place, set the glass block inside the opening. At this point, you may want to have a helper hold the window in place while you shim and level the block panel. 
  4. Now that the window is in proper placement, it's time to mortar around it to hold it in place. Keeping your shims in place, cut them flush against the window. Then, prepare your mortar according to the manufacturer's directions. Use your trowel to carefully apply it to create a sloping curb from the window base down (just like your old window had before - this helps with drainage). Allow the curb to dry, then apply the mortar to the sides and top of the window. Smooth them when they are beginning to dry using the trowel or a smooth tool.
  5. Allow the mortar to dry completely, then use your caulk gun to caulk around the window (between the glass and the mortar, and between the mortar and the concrete foundation). Smooth out the caulk using your finger. Then caulk the inside of your window as well in the same manner.

Installing a glass block window is fairly simple to do. The only downside is that this type of window cannot be opened. If you are looking for a window that can be opened/closed such as an egress window, it's best to contact a replacement window company to have it installed. You can also visit this page, or others like it, for more information.