Installation Guide

WOOD FRAME OPENING
INSTALLATION INSTRUCTIONS
Many frameless glass block windows are installed into masonry openings using mortar
to secure the window into place. But what if your project is going into a wood frame
opening? Mortar does not adhere to wood properly. Here are a couple of easy-to-
follow suggestions for installing new frameless glass block windows into a wood frame
opening.
SUGGESTION 1: USING LOW EXPANSION SPRAY FOAM OR FIBERGLASS
INSULATION
 Remove the Old Window
Remove the window sash and any hardware that will
interfere with the installation of the new glass block
window. Ideally remove everything down to the wood
framework.
 Install an Inside Stop
Assuming you are doing the installation from the exterior of the building, install an inside
stop on all four sides of the opening. The stops should overlap the face of the glass
block window on all 4 sides by at least 1/2 inch. If you are installing in a bathroom or
other wet environment, consider using a molding made of composite type material that
will not rust or rot for this purpose. Apply a heavy bead of high-quality silicone adhesive
such as REDI2BOND™ brand to all the edges of the stop that will come into contact
with the glass block.
 Install the Window into the Opening
Set the new window into place on top of 2 shims. Check that it is plumb and level; then
secure it with 2 shims at the top. You can use a pry bar to raise or lower the window,
adjusting the shims as needed, until it is square in the opening. Insert additional shims
to ensure the window is securely in place. Do not use shims directly above or below a
joint.
Note: If you are installing a vented window, the vent latch should be located on the
inside at the top.
Trim off the shims by removing the portion that extends beyond the glass block. You
may use a utility knife to cut the shims so that they are flush with the face of the glass
blocks. You do not want any part of the shim to protrude past the edges of the glass
block window.
 Fill with the Perimeter around the Window
Pack the perimeter joint full with either low expansion spray foam or fiberglass
insulation. Do NOT use high expansion foam.
When using spray foam, clean up any excess material immediately following the
directions on the can.