With the popularity of shower/bathtub combinations on the rise, more homeowners are requesting glass-block-enclosed showers. Tips to help avoid callbacks include:
Use only whole glass block units. Because of the partial vacuum in the block, drilling or sawing could cause the block to implode. Also, an installed cut-glass block will eventually form condensation, mold or mildew on the inside.
Know the proper mortar joint size. Typically in straight, flat walls, both horizontal and vertical joints vary in width from 1/4 inch to 1/2 inch. Reinforced joints should not be less than 1/4 inch or the cross wires of the reinforcing could point-load the glass block and cause breakage. In curved walls, the inside vertical mortar joints should not be less than 1/8 inch wide, and the outside vertical mortar joint should not be more than 5/8 inch wide.
Calculate the rough opening required. Assuming the use of spacers or a 1/4-inch-wide mortar joint, multiply the number of glass blocks by the nominal size and then add an extra 1/2 inch. Apply this formula to determine the width and height of the opening.
Attach the doorframe, but don’t let glass blocks support the door’s weight. Sling-type shower doors usually come with a perimeter frame that is anchored to the floor and supports the weight of the door. The glass block mortar joints may be used to attach the doorframe only, without providing the main support. Ideally the mortar joints should be 3/8 inch to 1/2 inch thick. Drill the mortar joints a little off center to be sure the drill bit does not nick the perimeter seal or any part of the glass block. Insert plastic plugs into the hole. Apply beads of sealant to the back of the frame before screwing the frame against the end of the glass block wall.