When a glass block window has a damaged glass block or two, it can really stand out and pose a safety hazard. Fortunately, it is possible to replace the damaged block(s) without having to redo the whole window.
Assessing the Damage
The first step in repairing a glass block window is to assess the extent of the damage. If the cracks or chips are small and localized, it may be possible to simply replace the affected block(s). However, if the damage is more widespread or the surrounding mortar is also compromised, it may be necessary to replace the entire glass block panel.
Identifying the Cause
It’s important to identify the underlying cause of the damage, as this will help determine the best course of action. Common causes of glass block damage include:
Extreme temperature changes causing the glass blocks or surrounding structure to expand and contract
Rusting of the steel reinforcement rods within the mortar, leading to concrete cancer and pressure buildup
Impact damage from projectiles or vandalism
Addressing the root cause is crucial to prevent further damage and ensure the longevity of the repaired window.
Replacing a Damaged Glass Block
If the damage is limited to one or two glass blocks, it is possible to replace them without having to redo the entire window. Here’s how to do it:
Removing the Damaged Block
Cover the damaged block(s) with strips of duct tape to contain any broken glass.
Use a rubber mallet to carefully break the glass block, taking care to avoid damaging the surrounding blocks.
Carefully remove the broken glass and vacuum the area to ensure no shards are left behind.
Use a hammer and chisel to carefully remove the mortar around the damaged block, taking care not to damage the adjacent blocks.
Installing the Replacement Block
Mix a batch of pre-mixed mortar to a bread-dough-like consistency.
Apply a layer of mortar to the bottom surface where the new block will be placed, ensuring the thickness matches the existing mortar joints.
Carefully insert the new glass block into the opening and center it.
Pack mortar into the spaces around the new block, both from the inside and outside of the window.
Allow the mortar to firm up for a few hours, then smooth and compress the mortar joints for a professional finish.
Clean the new block and surrounding blocks with a damp, soft cloth.
It’s important to choose a replacement block that matches the existing blocks as closely as possible in terms of color and size.
Replacing the Entire Glass Block Panel
If the damage is more extensive or the underlying cause cannot be easily addressed, it may be necessary to replace the entire glass block panel. This is a more involved process, but it can provide a long-term solution and an opportunity to upgrade the window.
The key steps in replacing the entire glass block panel include:
Carefully removing the existing panel, taking care to preserve the surrounding structure.
Preparing the opening by cleaning and repairing any damage to the wall.
Installing a new, properly waterproofed glass block panel, ensuring the use of galvanized reinforcement rods and appropriate expansion joints.
Sealing and finishing the new panel to prevent future water intrusion and damage.
This approach may be more costly, but it can address the root cause of the problem and provide a durable, long-lasting solution.