How to Install Glass Block Basement Windows

glass block
  • 3-4 hours
  • Advanced
  • 200-500
What You'll Need
Glass block window kit
Measuring tape
Power saw
Glass block window kits
Step ladder

Basement windows are important for bringing light into an otherwise dark and drab area; however, they can also create privacy problems. Homeowners who want outdoor light in the basement, but not for outsiders to be able to look into the basement, have one option. It is to build glass block windows. The project is relatively easy and requires minimal materials and tools.

Step 1 - Prepare for Your Window Installation

Any kind of construction usually requires a building permit. If a permit is required, get one before you begin your project. Purchase a glass block window kit from your local home improvement store. Measure and mark your wall where you'll be making the opening for your window. Use a level when marking the window's horizontal and vertical lines. If your first cut is crooked, you'll have trouble leveling the edge. Remove all materials from your kit and separate the parts into piles.

Step 2 - Cut Your Wall Opening

If your basement is finished, you will likely need to cut through two walls: the interior framing wall and the exterior wall. You'll need two different kinds of saws for this, a skill saw for your interior wall, and a concrete saw to cut through the concrete or cinderblock of the outer wall. Make the first cut into the interior wall, then saw through the exterior wall.

When cutting through the interior wall, be sure you not to cut through electrical wiring. If while working in the basement you'll be working in a spot where the wall that is over your head, you'll find it to be safer and less physically challenging if you use a step ladder. Avoid standing on anything as unstable as a box, bucket, or household chair.

Step 3 - Smooth Your Cut Edges

Use a circular saw with a grinder blade to smooth the rough edges of the concrete or cinder block opening into which you will insert your glass block window. Be sure to wear protective goggles while sawing because you'll have sparks and concrete fragments flying everywhere.

Step 4 - Insert the Window into the Opening

Remove the components and hardware from the window kit. At the outside wall, set the window into the opening you've just made. If necessary, use shims to level the window.

Step 5 - Install Fastening Hardware

Use the mounting hardware from your kit to secure one corner of your window. Check again to be sure your window is level, then fasten the corner across the first fastened corner.

Step 6 - Install Flashing and Apply Caulking

Use finishing strips supplied by your kit to complete the installation. Use caulking to fill the openings between the window frame and wall edges. Smooth any caulking that may have oozed out of the cracks.