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installer placing foam expansion joint between panels

6 Reasons to Use Foam Expansion Joints for Panelization and Prefab Walls

Prefabrication of exterior wall panels is ideal for quality assurance and consistent application, saving time and labor on the jobsite, and maintaining design flexibility for a beautiful, long-lasting façade. But what about where those panels come together on the outside of the building?
PF100 SE 430 Diagram Expansion Joints-2Next generation precompressed foam expansion joints can handle the weight and multi-dimensional movement of these panel-to-panel connections for an air and watertight seal with enhanced quality, labor-savings, and installation safety advantages over traditional joint sealing methods. This blog will dive further into 6 of the benefits of using foam expansion joints in panelization applications.

What are precompressed foam expansion joints?

Precompressed foam expansion joints are a weathertight primary seal that self-expand to fill the joint and are capable of up to +/- 50% movement from the mean joint size. Depending on the system selected, water resistance, fire resistance, and an integral sealant lamination can be incorporated into a single element, making it a popular option for prefabricated construction applications like modular, panelization, tilt up and other off-site construction methods.

The foam pieces are offered at varying widths, can be cut to any length, and are compatible with most commercial construction substrates, including metal, concrete, mortar, stone, and wood. You can also purchase the precompressed foam expansion joints with an additional pre-cured aesthetic sealant facer in a wide range of color options. Alternatively, you could install the standard foam joint and later apply your preferred wet sealant overtop. 

Sealing Panel-to-Panel Joints

Panelization of exterior walls differ project to project. Some jobs have elements of the wall or the full wall panels themselves assembled on-site and then installed. Others have the entire wall assembly, including the framing, drainage, sheathing, insulation, and cladding material, fabricated in a controlled, factory setting before being shipped to the jobsite and hung into place. 

Willseal_Panel_Project_2022_02_croppedWhile mechanical fastening and/or adhesives keeps the mounted panels secure, movement is inevitable, especially at the point where the panels meet, whether they are adjacent side to side or on top of one another. These expansion joints, as the name suggests, face significant expansion and contraction and are therefore critical to maintaining the air and watertightness of the structure. Any leaks could allow moisture into the wall cavity or the building itself, damaging the interior components and even leading to dangerous mold.

Sealant and backer rod was the traditional path for creating a primary and secondary seal at this connection. While still frequently used, in many cases, this option is tedious, subject to application irregularity, and vulnerable to cracking and pre-mature failure of the joint.

Precompressed foam expansion joints., on the other hand, solve these challenges and offer added consistency in panelization scenarios. Some expansion joint products, such as Willseal® PF200, can be ordered in custom depths to match the thickness of the panels while maintaining the plane of the air barrier. 

6 reasons to use foam expansion joints for panelization

Precompressed foam expansion joints solve these challenges with 5 key benefits:

  1. Enhanced safety
  2. Movement capabilities
  3. Durability
  4. Tested performance
  5. Labor savings with minimal learning curve
  6. Aesthetics

Enhanced safety with foam expansion joints

Building materials themselves can help foster safer construction practices whether on the jobsite or in-plant. The precompressed foam sticks can be installed to the exterior wall panel in a controlled factory-setting at waist level. Then when the wall arrives to the jobsite, it is ready to attach to the building using a crane, reducing the need for dangerous scaffolding, swing stages or lifts during the sealing process.

Movement capabilities of foam expansion joints

Panel-to-panel connections face movement in all directions and can be susceptible to damage, so precompressed foam expansion joints have emerged as the predominant technique for primary and secondary seals. 

As panels come together horizontally and vertically, these foam joints can withstand the weight of the panels and all types of building movement, including seismic conditions, while creating an air and watertight seal immediately after installation. In the sealant and backer rod method, during the hours that the wet sealant takes to cure, which varies by product, if there is any panel movement, the seal is broken and must be repaired or reapplied.

Durability of precompressed foam expansion joints

While precompressed foam expansion joints are flexible, they are also durable to resist the elements and incidental damage. Due to this resilience, foam expansion joints generally require much less maintenance than traditional sealants. 

Tested performance PF 100 Panel wall-cropped

The ultimate goal of the precompressed foam expansion joint is to prevent the passage of air and water into the wall cavity. With an air barrier integrated into the technology itself, the solution ensures a continuous air barrier across the building envelope. 

To test this condition for air- and water-tightness, the Tremco CPG Building Science Laboratory constructed a wall assembly using sheathing panels with a pre-applied air barrier membrane, Securock® ExoAir® 430, and Willseal® PF100 as the foam joint seal. The system successfully passed International Building Codes (IBC) and ASTM E283 for air leakage and ASTM E331 for water penetration up to 1200 Pa (25 psf), equivalent to a wind speed of 100 mph.

Labor savings with minimal learning curve

Labor savings is a huge driver for panelization. Precompressed foam expansion joints take this to the next level for a safer and less intensive application. They are easy to apply with minimal learning curve so no specialized training is necessary for installation. Plus, there is little prep work needed as the foam sticks have primerless adhesion to nearly any substrate. 

With wet sealant only required at the splice joints, there is less mess and reduced jobsite waste. In addition, precompressed foam joints are less restricted by weather, while traditional sealants have cold-weather limitations and curing concerns with precipitation. 

With standardized sizes of the precompressed foam joints, there is greater quality control and fewer applicator-related variables, such as fluctuations in sealant thickness or backer rod depth.

Aesthetics of foam expansion joints

For the architect and building owner, the final look of the building is critical. With precompressed foam expansion joints, while the main foam color is black, a pre-cured sealant facer can be incorporated in virtually any color for a uniform look as soon as the foam is installed. Alternatively, wet sealant can be applied after the foam is in place. 

Why You Should Use Precompressed Foam Expansion Joints in Panelization 

Enhancing the quality, time- and labor- savings, and beauty of a building with exterior wall panels, precompressed foam expansion joints are ideal for panel-to-panel connections because they can accommodate substantial movement, are durable, protect against air and water leakage, are safer and less labor-intensive, and deliver a consistent look across the building.

Learn more about off-site construction connections and installations in this blog post.