How to Install a Glass Block Window

Learning how to install a glass block window is an important step to changing out your tired old bathroom window and capitalizing on the sleek and ultra modern look of glass blocks. Best of all, because of their construction, they afford the privacy needed for a bathroom without the need for a curtain or other window treatments.

Crowbar and chisel
Measuring tape
Pad and pen
Glass blocks
2-by-4 inch wood planks
Shims (if needed)
Wood screws
Drill
Screwdriver
Level
Wood primer
Clear polyurethane
Paint brush
Glass block mortar
Trowel
Spacers
Glass block sealant

Instructions

- 1
  Remove the old bathroom window with the crowbar and chisel. Clean out any bits and pieces of wood and mortar that may be found in the window cavity. If you notice any termite damage, this is a great opportunity to replace some wood beams as needed.
- 2
  Measure the window opening carefully. Do not forget to calculate in the wood for the frame and also the layers of mortar. Glass blocks come in different sizes; most measure 4 by 8 inches, and others are as big as 12 by 12 inches. Calculate how many blocks you need to fill the window opening. If you need to cut some of the blocks, ask the customer service representative at your home improvement store if they will precut these blocks for you.
- 3
  Frame the future glass block window with the 2-by-4s, pre-drill holes for the wood screws with the drill, and then screw in the screws with your screwdriver. Make sure the frame is completely level. If needed, use some wood shims to slightly lift any of the wood planks in different spots to ensure that any unevenness or settling of the house that might have occurred is compensated for.
- 4
  Paint the completed frame with a stain or primer of your choice and then apply the clear coat of polyurethane. Do not skip this step or you may notice the wood beginning to bend and buckle because of moisture. Let the opening dry completely.
- 5
  Do a test run by placing the glass blocks in the window opening. If you are working with different-sized blocks, make sure you work out the pattern now.
- 6
  Prepare the glass block mortar for use, and spread a layer onto the bottom portion of the primed and sealed wood frame.
- 7
  Push the spacers into the mortar, and add the glass blocks. Place mortar in between the glass blocks as well.
- 8
  Repeat this process row after row, until your glass block window is in place. Scrape off excess mortar as you go and do not forget to do the same from the outside as well. Let the glass blocks settle and the mortar dry.
- 9
  Caulk the edges around the window with glass block sealant. Scrape off any overage.

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