Unitized curtainwall systems and methods

A method for installing a wall, comprising:

• installing adjacent wall units in a first row, thereby forming a joint between the adjacent wall units in the first row;
• placing a water barrier gasket on top of the first row such that the water barrier gasket spans the joint;
• and
• installing adjacent wall units in a second row on top of the first row, thereby forming a joint between the adjacent wall units in the second row that is aligned with the joint between the adjacent wall units in the first row,
• wherein each wall unit has a horizontal mullion that forms a gutter, the method further comprising installing a preformed, flexible gasket into the gutter across the joint to provide a flexible, waterproof seal on each side of the joint and maintain the flexible, waterproof seal under wind load and seismic activity and plugging a joint between four wall units with a preformed, flexible plug, wherein the joint between four wall units is plugged by compressing the preformed flexible plug between fingers to provide a compressed plug, inserting the compressed plug into the joint, wherein the compressed plug is configured to expand within the joint to form a seal at the joint between the four wall units.