Glass block can be used in several ways in the bathroom. Glass block windows are available in a limited number of sizes, and can be installed in a bathroom’s exterior wall. It’s much easier to install them during new construction, as opposed to removing an existing window and replacing it with a glass block version. That’s why most homeowners choose to hire an experienced contractor for this kind of retrofit. But DIYers can handle installing a glass block window in a partition wall, or building an interior wall with glass block. In this article, I’ll lay out the tools and materials needed, and the techniques required to work with glass block.

Before You Build with Glass Block

Most glass block projects are constructed not unlike laying out a row of bricks and mortar. In fact, special glass block mortar mix is the industry standard for its ability to connect the blocks strongly and safely. If you prefer, for small spaces or just for the aesthetic appeal, you can choose to use glass block silicone between blocks. To determine how many blocks you will need, or if you can use a pre-made block unit or kit, measure your space carefully before you begin. You’ll want to measure the width and height of the wall or window in several spaces, in case the existing space is not 100% plumb and level. Take the shortest of each measurement as your height and width. Because you’ll be putting mortar or silicone between the blocks, you’ll want the opening to be about one-half to 2-inches larger than the total measurement of the glass blocks. To compute your materials, know that the average glass block measures either 7.75- x 7.75-inches or 5.75- x 5.75-inches. Compare your measurements to decide what size of block you’ll need, and also any additional inserts, like block vents, sometimes used in glass block windows. Check for pre-made glass block kits at your local hardware store that may come in the dimensions you require, or purchase glass blocks and materials individually. See “Tools and Materials Needed” located at the bottom of this article.

How to Install a Glass Block Wall

Tools and Materials Needed

Glass blocks Glass block vent or screen panel (if using) Glass block mortar mix Mortar and grout mixer Glass block silicone (for finishing, or as mortar, if desired) Disposable gloves Brick trowel Glass block vertical and horizontal spacers (optional: wooden shims for bottom row leveling) Tape measure Level Cleanup rags Mixing bucket