How to Install Prefabbed Glass Block Windows

Glass block windows are an energy efficient way to beautify a home or commercial building. These windows have actually been in use since the Art Deco era of the 1920’s and 1930’s, but have seen a resurgence in their popularity over the last two decades. Prefabricated glass block is often made out of acrylic, making it lighter and easier to work with. Clear blocks are available, but textured and opaque blocks afford greater privacy while still bringing light to any space. Installation is simple and in most cases hiring a professional is not necessary. Read on for basic installation instructions.

Things You'll Need

• Prefabbed glass block windows, sized to fit your project area
• Utility knife
• Silicone sealant
• Plastic tracking
• Plastic spacers or cedar shims
• Plastic putty knife
• Latex caulking in a matching color
• Cordless drill
• Measuring tape (self-locking)
• Pencil
• Wood screws
• Laquer thinner and sponge

Instructions

1. 

   Measure the window opening on all four sides according to the directions provided. Ideally, this should be done from the outside. Measure and mark the plastic tracking with your pencil to fit each side. Cut the tracking according to the marked segments. A smaller plastic segment needs to be cut that is 1-inch wider than one glass block and only ½ the width of the tracking strip. Set this piece aside for the installation of the final block.

2. 

   Lay the measured tracking inside the window opening, with the open cut out at the top. Mark and drill pilot holes and attach the tracking with the woodscrews.

3. 

   Place the first glass block in a lower corner. Put a trimmed shim or spacer vertically next to it. Repeat with the next block until you have completed the first lower row. Keep the channel fitting tightly together. Top these blocks with a horizontal spacer and repeat until the window frame is filled almost completely. The final block will be placed where the segment was cut from the tracking strip. Apply a small bead of silicone to the portion that was set aside and press it into place to complete the block installation.

4. Use silicone sealant to seal all blocks horizontally. When applying vertically, avoid retracing the horizontal seams, and use the sealant sparingly. Repeat on both the left and right sides of the window and smooth it with a putty knife.

5. 

   Wipe away any silicone streaks with lacquer thinner and a sponge. Seal the interior and exterior of the window frame and the edges of the tracking with caulking to finish the project. Not only have you saved money by completing this project yourself, but you will also save up to 25% on your utility bills.

Tips & Warnings

• If your windows will be well over 6-feet wide, consider enlisting the help of a few friends or, for very large projects, hiring a professional.

• Prefabbed block windows also are available as a pre-assembled single unit, if your project is smaller and you would like an even more simplified installation.

• Heed all manufacturer recommendations. Do not attempt any procedural shortcuts in the installation of prefabricated glass block windows.

Resources

• Purchase glass block supplies here.
• Click here to view some of the types of glass block currently available.