For the first 78 years of life Glass Blocks were put together with mortar as if they were bricks. They aren't. In fact, mortar bonds poorly to glass.

The some people began using silicones that were not designed for structural glazing. They gapped, peeled, yellowed and sometimes totally failed.

Finally, someone invented a joint compound designed just for glass block. PowerSeal, the most powerful, flexible and long-lasting bonding compound ever used between glass blocks.

The high-modulus adhesive is perfect for structural glazing. It provides the security, translucent beauty and lasting bond that no other joint material can supply.

There's never been anything like it.

• Stronger, longer lasting joints that any prefab glass block window available.
• Easier to handle and install. Lighter. Virtually indestructible.
• Better Installation. No mortar to transfer cold.
• Gap-free barrier keeps rain outside.

PowerSeal Windows are stronger - virtually indestructible. They also provide better insulation since cold mortar joints are eliminated. All because PowerSeal was designed for use with glass block. You can see it in the superior bond and extra durability enjoyed by PowerSeal window owners.

Why should you use PowerSeal Glass Block Windows? The PowerSeal Glass Blocks are made with PowerSeal High Modulus Adhesive, specially formulated for the assembly of Glass Block Windows. Other sealants and adhesives just don't provide the strength and longevity. PowerSeal Windows have a designed-in "give" that virtually eliminates breakage and provides a bonding to Glass Block.

Below are some examples of the available shapes and colors: