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How to Install Glass Block Window in Wood Frame

Damon Koch

Installing glass block windows is a straightforward process. Most people install them in basements or in concrete openings, but installing them in wood frames or on other levels in the home involves the same process. With the correct materials and some preparation, you can do the job in a minimal amount of time.

Glass block combine security and beauty
  1. Remove the old window and window jamb using a wrecking bar and circular saw.

  2. Measure the rough opening making sure to subtract 1/2 inch from the length and the width. Purchase the glass block from a local home improvement store. If they don't have the correct size, you may have to fabricate a special window using a glass block fabricator, which you can find in the phone book or online.

  3. Screw the block of wood to the underneath of the top sill plate several inches from the outside edge of the hole. This is to prevent the window from falling inward during installation. You can determine how far in the block gets placed by seeing whether the glass block will set flush with the outside of the house or be inset somewhat into the frame.

  4. Set the glass block panel in place, resting it on the two wedges. It's a good idea to have a helper inside the house to prevent the bottom of the panel from sliding in.

  5. Center the panel in the opening using a tape measure to make sure there is an equal gap on each side. Gently pound the wedges in until the panel is setting up off the sill plate 1/8 to 1/4 inch.

  6. Place the level on the wedges and work the wedges until a level reading is achieved. Have the helper on the inside put the third wedge in the center of the panel.

  7. Mix the mortar in small batches and place on a piece of plywood for easier use. Build up the curb at the bottom first and let it dry. Make sure to stay away from the wedges. Pack mortar into the sides with the margin trowel and pointing trowel and after the mortar stiffens use the striking trowel to smooth it.

  8. Remove the wedges after the curb has dried for 2 hours and fill the gaps where the wedges were. Caulk the top of the sill plate on the inside and out. Wait two weeks before painting the mortar.