What are the Signs of Foundation Heave?

Foundation heave is a problem that occurs when the soil underneath a building expands upward after being saturated with water. It’s crucial to identify the signs of foundation heave early on to prevent further damage to the structure.

Understanding Foundation Heave

Foundation heave happens when the soil beneath a building expands upwards due to excessive moisture. This upward movement can cause serious damage to the foundation and the building itself if left unchecked.

Signs of Foundation Heave

Recognizing the signs of foundation heave is essential for addressing the issue before it worsens. Here are some common indicators:

• Cracks in Slabs: Look out for cracks resembling spider webs or chicken feet, especially where at least two cracks intersect. These cracks may form a triangle shape, indicating areas of significant heave pressure.
• Concrete Damage: Pay attention to any concrete damage occurring during or shortly after construction, which may worsen over time.
• Tree Distress: Trees near the building may start to fall or die within a year or two of noticing the first signs of distress in the structure.
• Upward Movement of Flatwork: Notice if driveways, patios, or garage slabs adjacent to the foundation appear to be lifting upward relative to the foundation.
• Water Leakage: Keep an eye out for water leakage from under slab plumbing or nearby pools or ponds, as this could indicate soil expansion beneath the foundation.
• Increased Soil Moisture: Check for an increase in moisture content in the soil beneath the foundation, especially if the soil’s plasticity index is greater than 25.
• Soil Probe: The soil beneath the perimeter beam may feel soft and easy to probe, suggesting potential heave.
• Out-of-Level Pool: If there’s an in-ground pool near the structure that appears to be out of level, it could be a sign of foundation heave.
• Poor Drainage: Ensure that the site’s drainage slopes away from the foundation to prevent water accumulation around the structure.
• Muddy Soil: Excavating around the foundation may reveal wet, muddy soil in the upper few meters below the perimeter grade beam.
• Loose Gaps: Loose gaps between grade beams, piers, or foundation repair shims could indicate movement caused by heave.
• No Space at Grade: If there’s no space between the perimeter grade beam and the adjacent soil at grade, it suggests potential soil expansion.
• Disproportionate Damage: A large amount of damage to the foundation and superstructure compared to the level distortion in the foundation is a clear indicator of heave.
• Flooring Damage: Damage to ground-level flooring materials, such as tiles or hardwood, may occur as a result of heave.
• Bowed Slabs: Slabs may appear bowed between grade beams, with the beams connected to piers constructed below the active zone.
• Cracks in Walls and Frames: Look for cracks in drywall and brickwork, often in zigzag patterns, as well as misaligned door and window frames due to upward pressure on the foundation.

Conclusion

Identifying the signs of foundation heave early on is crucial for preventing further damage to the building. By paying attention to these indicators and taking appropriate measures, property owners can mitigate the effects of foundation heave and ensure the stability of their structures.