Engineered Wall Void Forms for Structural Concrete
Wall void forms are used beneath structural walls and grade beams, between piers, to create the engineered void space required in expansive soil conditions. That void allows soil movement to occur without transferring pressure to the wall, helping protect the structure from cracking, uplift, and long-term damage.
At Carton Forms LLC, our wall void forms are hand-assembled in Denver, Colorado, built with an understanding of engineering requirements and the height of liquid concrete pours.
When walls are designed to be partially suspended, the void below them must perform exactly as intended.
Why Use Wall Void Forms
Structural walls and grade beams are designed to carry loads, not absorb soil movement. In expansive soils, wall void forms provide the separation engineers rely on to keep vertical soil pressure from stressing the concrete.
Wall void forms are used to:
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Create consistent void space between piers, beneath structural walls
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Reduce upward pressure from expanding soils
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Maintain proper load transfer through the wall system
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Protect long-term wall performance
Used correctly, wall void forms help eliminate movement-related damage before it becomes a problem.
How Wall Void Forms Work
During placement, the corrugated carton structure supports reinforcing steel and wet concrete loads. After the concrete cures and becomes self-supporting, the form absorbs moisture and begins to weaken as designed.
As soil expands, it moves into the void space rather than pushing against the wall or grade beam. This controlled collapse is intentional and critical to long-term performance.
The objective is simple:
Allow soil movement without transferring force into the wall.
Construction & Materials
Carton Forms wall void forms are manufactured using proven construction methods designed for predictable performance:
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Wax-coated exterior cover to resist moisture during handling and placement
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Corrugated cellular interior designed to support wall and beam pours
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Water-based adhesive selected for controlled degradation
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Consistent geometry to maintain continuous void space beneath walls
Forms are hand-assembled for uniformity and inspected to ensure consistent strength and performance.
Applications
Wall void forms are commonly used in:
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Structural foundation walls
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Grade beams
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Stem walls
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Shear walls
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Residential and commercial foundation systems
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Any condition where walls are designed to be partially suspended above expansive soils
If a wall detail calls for a void space product, the performance of that void matters.
Installation Considerations
Proper installation plays a major role in wall void form performance. Best practices typically include:
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Store forms off the ground and keep dry prior to installation
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Place forms on smooth, even subgrade
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Install forms tightly, end-to-end, to maintain continuous void space
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Protect from puncture, crushing, or point loads
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Prevent concrete intrusion into void areas
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Use protection board on the entire form surface
If site conditions differ from standard details, we’re available to help review alternate products and approaches before placement.
Compatible With Protection Board and Soil Retainers
Wall void forms are often paired with:
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Protection Cover Board to shield forms during reinforcement and concrete placement
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Plastic Soil Retainers to prevent lateral soil movement into the void space
Together, these components help maintain clean, functional void conditions at structural footings.
Why Contractors and Dealers Use Carton Forms Wall Void Forms
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Build forms to meet engineering specifications
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Predictable, consistent performance
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Hand-assembled quality
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Designed with real jobsite conditions in mind
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Technical experience you can lean on
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Reliable delivery and clear communication
Nothing is assumed. Everything is earned.
Availability & Support
Carton Forms wall void forms are available through local concrete supply dealers. If questions come up around specifications, or take-offs, we work alongside our dealers to offer optional product and installation methods, that help ensure the right solution is quoted and supplied.