Should you use a unitized curtain wall or a stick-built curtain wall?

Curtain walls are a defining feature of many of today’s most iconic buildings, but it comes as a surprise to many that curtain walls have been around since well before the 1900s. Originally constructed as a light and airy alternative to typical masonry walls, many things --including how these walls are built-- have changed drastically since then. Once made with structural steel beams and only constructed on very rare occasions, it was not until the introduction of faster techniques and higher quality materials produced over the last century that these sturdy yet light, non-structural exterior wall designs became readily available to the public. Curtain walls are now accents to a multitude of structures all over the world from skyscrapers to personal residences, be it large or small.

If you are looking to start a curtain wall project but have not yet committed to the idea of using a unitized or stick-built method, worry not. When armed with the right information, narrowing down the options that will fit your individual and business can be relatively simple. Keep reading below to find out if a unitized curtain wall or stick built system is right for your project.

What is a curtain wall and why are they so popular in architecture today?

Curtain Walls - Curtain walls are a self-supporting and structurally independent system that usually span over a distance of multiple stories. They are described as lightweight non-structural outer walls, are often aluminum-framed and contain in-fills of glass, metal panels, or thin stone. These particular walls are not made to be structurally bearing except under their own weight.

It is because of their lack of structural integrity that they can be crafted out of aesthetically pleasing lightweight materials, such as glass, that coincidentally also happen to be well suited to resist elemental forces such as wind, water and even seismic activity. They are specifically designed to withstand with the supporting structure and can be customized to suit nearly any project. The pliability and durability of curtain walls under the array of such stressors makes them a highly regarded construction choice, especially for tall and otherwise cumbersome structures where flexibility is must have. Glass curtain walls are particularly popular in today’s structures, largely in part to the natural light penetration aspect.

There are two common types of curtain walls, both of which are rather similar in many aspects including their flexibility, hardiness and customizability, but it is the way in which they are fabricated and installed that ultimately classifies them as either “stick-built” or “unitized” (also known as “modular”) curtain wall systems.

Stick-Built Systems - As the name suggests, “sticks” (extended pieces of aluminum) are inserted vertically and horizontally between floors, building the frame (mullions) that will later be used to support the enclosing panels. Stick built systems are typically found in vertical and polygon facades, and while they may work well for many of these projects, one of the greatest downfalls to this method is that a number of processes are required to erect the walls.

In order to install a stick-built curtain wall, each panel unit must be connected and sealed piece-by-piece, which means more time --estimated up to 70% of the project-- is spent doing so on the construction site. This method, more often than not, requires a team of skilled installers to remain on site, which can be not only time consuming, but expensive. Furthermore, the quality of stick-built systems can be heavily affected by things like the local environment and on site handling.

Unitized Curtain Systems (aka Modular Systems) - Alternatively, unitized curtain systems, frequently referred to as “modular systems,” are large glass units, typically about one story tall. Unitized systems are repeatedly commended for their quick installation rates, which can be up to one-third of the time it takes for stick-built systems, and their exceptional quality. The panels are pre-fabricated and assembled prior to arrival; this allows for fast assembly on site as the panels will only require hoisting into their specified location. Subsequently, the quality of these panels are much easier to control as most of the assembly and handling occurs where they were manufactured, in a controlled environment.

This method takes advantage of the speed and quality of prefabrication techniques, reducing installation time and requiring fewer skilled laborers on the job site, overall, this can dramatically lower job site costs. Modular systems are often utilized on large volume projects, including those with higher field labor costs and where higher performance material is a necessity.

But the question still remains, should you use a unitized curtain wall or a stick-built curtain wall?

While there is no “one size fits all” answer to this question, for larger, taller and higher-quality projects, the answer will likely be a unitized curtain wall. If you are a contractor or architect that prefers a quick, seamless and competitively-rated job the first time around, the unitized curtain wall system cannot be matched.

But, no matter what you choose, there is no debate that curtain walls not only look good, they are very effective at what they do. Crafted for style and endurance, it is no wonder how curtain walls have become such a popular design feature seen on high end buildings and structures found throughout the globe.

Crawford-Tracey Corporation

Founded in 1956, Crawford-Tracey Corporation has become the largest contract glazier & window manufacturer based in the state of Florida, the company offers a complete line of impact and non-impact-resistant window and door products. Crawford-Tracey designs, manufactures and installs all of its products. Crawford-Tracey developed, tested and installed the first impact-resistant, four-sided, structurally glazed system in the United States and continues to offer high-performance products to meet specific project needs. Crawford-Tracey’s corporate headquarters is located in Deerfield Beach, Fla., with a second facility in Jacksonville, Fla. For additional information on Crawford-Tracey products and services, visit www.crawfordtracey.com, or call 954-698-6888