February 2023
That underground garage is more than a place to park your car. When repairs are required, they cannot be put off like a common area renovation without consequence.
The typical underground garage is constructed from the lowest level up to include:
- Concrete slab at the lowest level lightly reinforced with wire mesh or unreinforced.
- Suspended slab with reinforcing steel bars above the ground and typically covered by a waterproofing membrane to protect the structure from water and salt infiltration.
- Roof slab or deck which is often exposed to the outdoor elements. It is protected by a waterproof membrane and may be covered by grass, landscaping, concrete, asphalt and walkways.
- Throughout the structure are columns and beams to reinforce the structure; drains that should be located to remove potential ponding water; and expansion joints to support movement of the garage structure while remaining water-tight.
Deterioration in the parking structure is identified by visual observation and various testing methods to identify corrosion, water infiltration and damage to concrete or other elements of the structure. Damage can result from water, salt or other contaminants, and general use.
Brown & Beattie Building Science Engineering works with condominium corporations to repair and maintain their underground parking areas. Once damage is identified, they advise that “further damage and higher repair costs can be averted by repairing sooner rather than later. Localized repairs defer the need for major structural repair or replacement. In the case of a water leak, immediate resolution can avoid damage to the concrete slab or metal corrosion which are more costly to repair.”
For communities more than 20 years old, an underground garage should be assessed about every five years or as-needed once problems are identified. An assessment determines the overall state of your garage structure and can set out a timeline for major and minor repairs to maximize its lifespan.
