It is crucial to exercise caution while choosing and setting up window wall systems for your home. Inadequate product selection or faulty installation can lead to issues such as water and air leakage, mold growth, condensation, and even structural harm. These are complications that everyone would prefer to avoid.
Now, let’s explore effective measures to prevent these issues from arising.

1. How Are Window Walls Built?

Typically, window walls are constructed using one of two methods: factory-built or on-site construction.

Factory-built windows are manufactured away from the construction site in a controlled environment. Once completed, they are transported to the job site and installed by setting them into the designated wall openings. These pre-fabricated units are typically secured in place using anchors, clips, or nailing flanges.

On-site construction of windows involves assembling the window systems directly at the job site using components delivered from the factory. This method often applies to more intricate window systems.
While site-built window installations tend to be costlier and carry a higher risk of errors if not handled properly, they have the potential to create exceptionally well-crafted window systems. Optimal results can be achieved by ensuring the use of high-quality products and hiring reputable installers. It is essential to conduct thorough research on the reputation of installers before proceeding with site-built window walls for your home.

Typically, the majority of windows are constructed in a factory setting. However, with the increasing popularity of larger window wall designs, manufacturers are adapting by fabricating individual windows that can be securely connected or joined together. This process, known as mulling, can help save time and costs when performed in the factory. However, if the size of the window wall layout is too large to be built and transported safely, manufacturers may opt to mull some units together in the factory and leave the remaining units to be securely connected on-site during installation.

2. How Are Window Walls Installed?

Window wall systems are installed using one of two methods: concealed anchors, clips, and fasteners, or nailing flanges.
In window walls utilizing anchors and clips, the system is typically secured to the sides, top, and bottom of the wall framing. This ensures a stable connection to wall studs, blocking, and headers.

Windows equipped with nailing flanges are affixed to the wall by securing them through the exterior sheathing.

The primary distinction between these two installation methods lies in how the flashing and water-resistive barrier are implemented. In installations featuring anchors and clips, the flashing and water-resistive barrier extend into the window opening. The small gap around the windows is then sealed using sealant and backer rods. On the other hand, with a nailing flange, the flashing is installed over the nailing fin in an overlapping manner, ensuring water is directed away from the window opening. While there is a slight variation between the two installation types, it is crucial to note that both methods can result in significant problems if not executed correctly.

3. What Type of Window Wall Installation is Best?

Several factors influence the choice of window wall installation for your project:

• Complexity of the window wall design.
• Selection of a reliable window wall company.
• Experience level of your general contractor.
• Personal comfort, preferences, and budget.

Neither installation method is inherently superior or inferior, as long as they are executed correctly. Some experts favor nailing flanges because they cover the gap between the wall and window frame. However, for larger window walls, nailing flanges may not be feasible. When installed properly, both methods can achieve a fully waterproof system.

To ensure a proper installation, it is advisable to engage qualified installers and professionals with experience in window wall installation. Depending on the specific window wall product, some companies may provide their own trained installers, while others may recommend reputable installers. Alternatively, you may be responsible for finding your own installer.

By engaging skilled professionals and adhering to manufacturer recommendations, you can enhance the likelihood of a successful window wall installation that meets your requirements.

4. The Importance of Proper Window Wall Installation

Emphasizing the significance of proper window wall installation cannot be overstated. Correct installation is crucial for preventing leaks and ensuring that conditioned air (heated or cooled) remains inside.

Integral to the success of the entire wall assembly is the seamless integration of the water resistive barrier and window/door flashing. Flashing plays a vital role in diverting water away from the window opening, directing it onto the water resistive barrier, which then safely channels the water out of the wall.
Improper flashing and sealing of window walls can result in water and air infiltration, mold growth, and damage to interior finishes. These are complications nobody desires.

A solid window wall installation commences even before the windows are installed. Depending on the specific window wall system, whether it employs anchors and clips or nailing fins, careful consideration must be given to the sequence of window, flashing, and water and air barrier installation. There exists a precise order for installing each component, and any deviation from this sequence increases the risk of wall failure.

This construction sequence ranks among the most critical aspects to execute accurately. We have witnessed instances where contractors neglected to install flashing correctly or failed to overlap the water-resistive barrier in a shingled manner (to ensure proper water drainage). Had these errors gone unnoticed, construction would have proceeded, concealing the faulty work, and likely leading to future leaks.