Installing Speedset Glass Block Windows

Speedset glass block windows come already assembled. They often have a vent in the center so they're very useful for bathrooms or areas that you'd like to either let out the moisture or let in fresh air. They are really panels of blocks pre-connected and then banded together rather than complete windows with frames. The bands prevent knocking a block off during installation.

Measure

Measure the area carefully. When you use Speedset glass block windows, remember, they don't have a regular frame holding them together but a band around the outside. It doesn't show once you install the window and makes it look as though you installed the blocks one by one. Allow enough room for the mortar. Make sure you have the appropriate size window for the opening. You'll need to add 1/2 inch to the size of the glass block panel on all sides for the mortar.

Tear Out

Tear out the old window, remove the frame and clean the area thoroughly before you continue. Any debris left compromises the strength of the installation. If you have masonry walls, slightly dampen them.

Shim

Place shims in the corner and about every 2 1/2 to 3 inches on the base of the window frame. Start at the corners. You'll need to shims to be about 1/2 inch to allow for the mortar.

Prepare

Put a layer mortar on the bottom of the window opening. The manufacturer often recommends specific mortar. Portland cement and sand work very well for this type of installation.

Install

Snug the Speedset glass block window panel into place. Shim the upper portion between the window and the opening. You should have about a 1/2-inch gap there also. Adjust the gap on the top and the bottom so they're even. Center the window so it's also even on the sides.

Mortar

Fill in the sides and bottom with mortar. Check for any gaps in the cement, particularly at the bottom of the window. Use gloves when you do this to protect your hands. Smooth out the surface and allow it to set up for about two hours, then remove the shims and pack the gaps left by the shims with more cement. Blend in the new cement to match the first.

Completion

Wait at least a full day before you caulk the top. If necessary, fill in the gap first with a foam caulking backer rod. Leave only about a 1/2-inch gap to caulk. Use only 100 percent silicone to caulk the area. If you dribble or smear the caulk, use denatured alcohol to clean up the silicone on your newly installed Speedset glass block windows.