Commercial Retaining Walls and Sunken Areas

There were multiple retaining walls at the recreational facility shown in the video. Some were holding back soil to manage changes in grade due to the site’s topography, while others supported stairways providing access to below-grade areas. The inspection approach and common deficiencies remain consistent for both applications, with below-grade areas adding additional inspection points related to safe egress. For a comprehensive overview of commercial retaining wall inspections, take the Inspecting Commercial Building Exterior Systems and Features Online Course.

Retaining Wall Basics

A retaining wall is a structure designed to hold back soil, prevent erosion, and stabilize slopes. Beneath the wall, the footing or base provides a stable foundation. Behind the wall, backfill supports the structure and helps transfer pressure into the surrounding soil.

To limit damage from water, drainage features are incorporated to allow trapped moisture to escape. Depending on the design, some retaining walls also include structural reinforcement elements that extend and anchor into the surrounding soil. Altogether, retaining walls distribute pressure and loads across the structure to help prevent movement or failure while supporting grade transitions. Learn more about retaining wall constructions and common deficiencies in the Inspecting Retaining Walls at Commercial Properties article.

Sunken Area Inspection Points

Below-grade exterior areas are often referred to as sunken areas. They are portions of ground or walking surfaces that sit lower than the surrounding grade and may serve as egress or exit paths from lower levels of a building. Because these areas tend to collect rainwater, snow, or ice, proper drainage is critical. Inadequate drainage can create safety hazards and interfere with the accessibility and function of emergency exit. Retaining walls commonly protect or adjoin sunken areas.

Stairs

Sunken areas typically require stairs for access. Stairs are subject to the same safety principles whether they are interior or exterior. For every 12 feet of vertical rise, a landing is typically required. While inspectors are not code enforcement officers, they can note in their report when stairs appear to lack a landing that may be expected under modern construction principles. Note any trip hazards, uneven treads, or other conditions that could affect safe egress.

Handrails and Edge Protection

Handrails should be continuous, graspable, and extend beyond the bottom tread to provide adequate support. Terminations should be designed to prevent snag or hook hazards. Inspectors should note missing, damaged, or improperly configured handrails that could compromise safety. Edge protection is required wherever there is a drop greater than 30 inches. Guardrails or barriers should be secure, have no openings large enough to allow a 4-inch sphere to pass through, and be capable of withstanding lateral pressure.

Learn more about inspecting stairways in the Stairways, Railings, and Guards Inspection Checklist.

Retaining Wall Inspection Approaches

Two primary inspection approaches are used to assess the structural integrity of retaining walls and the severity of observed conditions.

First, inspectors typically begin by verifying that the wall adheres to basic construction principles, including:

• Plumb: Observed for vertical alignment along the full height of the wall.
• Level: Observed for horizontal consistency without noticeable slopes or irregularities.
• Square: Observed from a distance to identify walls that lean inward or outward.
• Straight: Observed by sighting along the wall to identify bowing, waviness, or unintended curvature.

Inspectors should also check the surface area behind the retaining wall. Dips, slumping, or uneven grades may indicate settling of the backfill. The wall and surrounding surface should appear intact and continuous.

The other approach involves viewing the structure through both a macro and micro lens. The micro lens focuses on localized wall conditions, such as cracking, deterioration, or joint separation. The macro lens provides contextual insight into the extent of cracking, overall movement, and the wall’s relationship to surrounding grades and site features.

Combining these approaches allows inspectors to connect the dots between individual defects and the wall’s overall condition.

Inspector Takeaway

Retaining walls, sunken areas, and exterior stairs are interconnected features that contribute to the overall functionality, safety, and structural integrity of a property as a whole. Observing one area often provides insight into related conditions. For example, a crack in a retaining wall may signal soil pressure issues that could affect the stability of nearby stairways or landings. Understanding how these components relate allows inspectors to connect the dots, identify maintenance and repairs, consider potential risks, and present a clearer picture of a property’s condition.