When installing glass blocks for light, be sure to reinforce them properly to prevent cracking and shifting. Mortar and caulk them snugly to prevent leaks.. Follow these steps to install a reinforced glass block wall.
Step 1 - Reinforce the Floor Below the Glass Block Wall
Glass block is very heavy, so a wall section may break through the floor. Reinforce the floor below the glass block wall with 2 layers of 2x6-inch plank. Use 2x8-inch planks if your glass blocks are wider than 6-inches.
Step 2 - Construct a Supportive Frame
Measure and purchase a polystyrene foam base for the glass block wall. This base is more costly than others, but it will reinforce the glass block wall most effectively. It will also resist moisture. Install the glass block wall panel between the wall studs to reinforce the structure.
Step 3 - Lay the First Row of Glass Blocks
Lay the first row of glass blocks, inserting plastic spacers to allow room for the mortar. Remove the spacers as you fill the spaces between the glass blocks with mortar. When the mortar oozes from the space, you have applied enough. Wipe excess mortar immediately with a damp sponge.
Step 4 - Insert Vertical Support Rods
Once you have laid the first row of glass blocks, insert 1/8-inch vertical steel wire support rods. Add a vertical support after every 2 horizontal blocks that do not abut wall studs. Cover the support rods completely with mortar. Continue laying blocks horizontally till you finish 3 rows.
Step 5 - Add Horizontal Steel Wire Rods
After each 3 rows of glass block, drill a hole into each side wall stud at the top of the blocks. Lay a steel wire reinforcing rod into the mortar on the top row of blocks, so that it touches the vertical support rods. Press the rod firmly into the mortar. Insert the ends into the drilled wall holes.
Step 6 - Allow the Mortar to Set
Once the glass blocks have been laid and mortared, allow the mortar around the blocks to set for 36 hours. Scrape away any dried mortar crumbs from the glass block faces carefully with a plastic scraper or putty knife.
Step 7 - Caulk Around the Perimeter
Use the caulking gun to apply a thin bead of clear waterproof silicone around the perimeter of the glass block wall. Press the caulking into any gaps between the wall and the glass blocks. Remove excess caulking immediately. Allow the caulking to set for 24 hours.