Project Guide

How to Install Glass Block

men measuring glass block installation area

Whether you are installing a glass block window or a wall, The Home Depot has different glass block sizes to complete the project.

  • Use a tape measure to measure the area where you are installing glass block and determine the glass block sizes that will fit.
  • Use a level to even out the installation space.

Tip: Draw a diagram of the intended installation to set a foundation for installing glass blocks in your windows, bathroom or kitchen.

Installing the Right Glass Block
two different types of glass block styles

The Home Depot offers different types and sizes of glass block to accommodate your glass block design including diamond, ice or ribbed styles. Be sure to choose the matching corner glass block to complete your project.

  • Size: Most common sizes are 7.75- x 7.75-inch and 5.75- x 5.75-inch.
  • Decor: Choose a clear glass block with a pattern for decorative accents. 
  • Privacy: Choose a glass block with a stronger pattern and opaque glass for enhanced security.
Mix the Glass Block Mortar
a bucket of glass mortar mix for glass block installation
  • If your product does not provide instructions on how to mix the glass block mortar for this project, it is recommended to mix white masonry cement, mortar cement and sand with water. 
Apply Bed of Mortar to Level the Surface
man applying mortar to wall surface
  • Using a trowel, apply a bed of mortar to the surface.

Tip: For uneven project areas when installing glass block windows with mortar, you can adjust fit with the mortar mix or add glass block spacers that will give you up to an inch between each glass block.

Add Glass Block to Surface
glass block wall with spacers partially installed
  • Create your first row of glass blocks by adding each block one by one.

Tip: Be sure to level as you work.

Reinforce When Installing Glass Blocks
glass block spacers
  • Fix anchors and reinforcing rods every two feet to provide strength and stability when installing glass blocks.
Clean Mortar Residue
person cleaning glass block
  • Repeat the above steps until you’ve completed the wall.
  • When installing glass block windows with mortar, use a damp cloth to clean any stray mortar or residue off the faces of the block.
  • Allow the mortar to cure and settle into the glass block for 24 to 48 hours.

Tip: If temperatures are exceptionally hot, the mortar will need to be kept moistened and allowed to naturally dry during the curing period. If necessary, use a spray bottle with water on the glass block and cover or surround the glass block area with plastic or a large trashbag.

Seal the Glass Blocks
sealed glass block window in bathroom
  • When the mortar has completely set, seal the perimeter and joints with a glass block sealant.