Preparing to Install a Glass Block Window

When you go to install a glass block window you will want to ensure that several of the standard bases are covered before actually mortaring them into place. Positioning, size, length and height needs to be taken into account, and also the direction the blocks are installed to prevent water and moisture buildup in the central cavity. Most of these blocks have a molding hole, where the outer end of the glass is open to allow moisture to escape from inside the chamber. These are all things to take into account before taking on this project to escape potential repairs in the long term.

Measuring and Widening the Opening

Before installing your glass block window or windows, you'll want to take exact measurements of the opening you are going to install them into. Be sure you have enough room for the block, or if you are going to need more than one to do the job. You can not cut these blocks and then install them, as it will break their efficiency in the long term. You will want to make your opening bigger to fit a second block if one will not do the trick, or perhaps plan on shoring up the opening so your glass block will create a tight seal.

Check for Cracks, Breaks or Hairline Fractures

Before buying your glass block window pieces, be sure to check them for breaks or imperfections. Blocks that are being installed that are going to be exposed to the outside temperatures of your home should have a breather hole in them. Solid glass block is for indoor applications as they are not effected by dual temperature changes from the inside and outside of your home or office. Condensation will not build in those types of blocks inside your home, unless they separate two different rooms that are at two separate temperatures, this is also something to keep in mind.

Insert the Blocks Blow Hole Downwards

Most standard basement windows will take 2 glass block windows to fill the windows opening or gap. Two glass blocks are pretty standard on most traditional as well as modern homes for filling basement window openings. Be sure that when you are installing these blocks that the hole is facing down toward the ground, this allows moisture to drain out the bottom and not get caught in the glass chamber, you can also add a thin plastic sheet under them to help prevent water from draining onto your foundation wall.

Rubber Sealants

There are a number of rubber sealants and insulators that can be incorporated into your glass block window project to help keep a tight seal between your home and the outdoors. These types of temperature sealing products are not needed for indoor glass block construction, and suggested for glass blocks that are exposed to outdoor temperatures. This material is inserted in the center of your blocks around the center of your joints as they are being installed. You then grout the inside and outside joints where they come together, giving an air tight seal to your finished project.