Glass Block Window

Bathrooms in many older homes have a window in the tub area - a problem when outfitting the bath with a shower. To ensure privacy, consider replacing it with a panel of glass block (see photo). You can buy preformed panels in limited sizes or build one yourself, allowing the mortar to cure as recommended by the manufacturer.

 

Glass block windows bring
in the sun -- with privacy.

• Glass block panels
• Wood shims
• Temporary stop blocks
• Expanding-foam insulation
• Utility knife
• Mortar
• 6d finishing nails
• Caulk
• Primer and paint, if desired

1. Remove parting stops from window jambs to free sash. Interior casing (the trim surrounding the window frame) can remain in some cases. Remove sash and any cords, weights, pulleys, etc.

2. Place tapered wood shims on windowsill, and set the glass-block panel in place from the inside. If exterior trim or stops on the old window frame won't prevent the glass-block assembly from falling through the opening, fasten a couple of temporary stop blocks in place. Adjust the wood-sill shims to level the block assembly, then place shims at the top and sides to secure it. Make sure the face of the glass block panel is flush with the inside edge of the window frame, for fitting wood or tile trim later.

3. Spray expanding-foam insulation to seal the space between the panel and the window frame; let dry. Trim the excess foam with a utility knife.

4. Working from the outside of the window, fill the bottom gap (between windowsill and glass block) with mortar; let set for 15-30 minutes, then remove wood shims and plug those gaps with mortar. Cut and fit cedar 1x stock as trim around the sides and top of the window exterior. Secure with 6d galvanized finishing nails. Caulk all edges where cedar trim meets glass and window frame.

5. Prime and paint all exposed wood surfaces, including mortar joints between blocks, if desired.