Retaining Wall Issue at Vistana Heights (Part 2)

                                 A ledge behind one of the houses which has been re-cemented 

                             at least 3 times in the last year. The crack above is a serious matter.

This is a continuation of my post found here. 

Cementing the ledge of a cliff over 20 feet high to prevent collapse is a superficial and inadequate solution for several reasons:

Structural Insufficiency: Cementing the surface of the ledge of a cliff does not address the underlying geological instability. Cliffs are subject to natural forces like soil erosion, water seepage, and gravity, which can cause landslides or collapse. A thin cement layer lacks the structural integrity to stabilize a 20-foot cliff, as it doesn’t reinforce the deeper soil or rock layers. Proper retaining walls, engineered with deep foundations, drainage systems, and geotechnical analysis, are typically required.

Water Movement and Pressure: Water from the ground in the house compound, including rainwater or groundwater, will continue to seep into the soil behind the cement. Since cement is impermeable, it traps water beneath, increasing hydrostatic pressure. This can weaken the soil structure, leading to cracks in the cement (as observed) and eventual failure of the cliff face. Without proper drainage systems, such as weep holes, French drains, or perforated pipes, water will accumulate and exacerbate erosion or slippage.

Crack Formation: The recurring cracks in the cemented ledge indicate ongoing soil movement or settlement. These cracks allow water to infiltrate, further destabilizing the soil and creating a cycle of erosion and collapse. The cementing approach ignores the root cause—lack of structural support.

 

Water Drainage Concerns: If the house compound lacks proper drainage, water will either pool on the surface, causing flooding, or seep into the ground, flowing toward the cliff. Without a designed drainage system, this water will likely move downward and laterally through the soil, pooling behind the cemented surface and increasing pressure on the cliff. Over time, this can lead to catastrophic failure, especially during heavy rain.

Recommendation: A geotechnical engineer should assess the site to design a proper retaining wall with adequate drainage (e.g., weep holes, gravel backfill, or drainage pipes) to redirect water away from the cliff. Regular monitoring and maintenance are critical. Cementing alone is a stopgap measure that risks long-term safety and property damage, as evidenced by the ongoing land slippage and cracks at Vistana Heights. The houses may remain unsafe until these issues are addressed comprehensively.