What are the main differences between unitized and stick curtain wall systems?

Unitized and stick curtain wall systems are the two principal approaches to metal-glass façade construction, each suited to different project needs. Unitized systems are factory-assembled modules (typically one floor high) that arrive at site pre-glazed and pre-sealed, enabling rapid installation and high quality control — an advantage on high-rise projects in Dubai, Abu Dhabi and Doha where logistics, site labor constraints, and weather windows are limiting factors. Unitized systems minimize on-site tolerances, reduce exposure to dust and sand during assembly, and generally deliver better airtightness and water-tight performance because fewer field joints are required. Conversely, stick systems consist of individual vertical mullions and horizontal transoms installed and glazed on-site. Stick systems offer flexibility for complex geometries, phased installation, and easier adjustments to building irregularities, making them suitable for bespoke low- to mid-rise buildings and projects with limited crane access. However, stick systems require more on-site labor, more field sealant joints, and careful site QA to achieve the same performance levels as unitized systems. For Gulf conditions where sand, humidity and temperature swings present durability challenges, we often recommend unitized metal-glass curtain walls for tall towers because they deliver consistent factory-controlled sealant application, thermal break assembly and glazing quality — translating into lower long-term maintenance and superior weather performance.