Parking garage inspection basics

A parking garage inspection is a structured look at the concrete, waterproofing, drainage and building systems of a parkade to find deterioration before it becomes a safety problem or an expensive repair. In Canada the main enemy is chloride from road salt, carried in on vehicles and driven into the concrete by water and freeze-thaw cycles. Regular inspections let owners plan repairs on their own schedule instead of reacting to falling concrete.

Why parking structures deteriorate

Parkades are exposed to harsher conditions than almost any other part of a building. Every winter, vehicles drip salty slush onto the slabs. That water soaks into cracks and pores in the concrete and carries chlorides down to the reinforcing steel. Once enough chloride reaches the steel, it starts to corrode. Rust takes up more volume than the steel it came from, so it pushes the surrounding concrete apart. The result is cracking, delamination (a hidden layer separating inside the slab) and eventually spalling, where pieces of concrete break off.

Other contributors include:

• Freeze-thaw cycling, which breaks down concrete that is saturated with water. See freeze-thaw damage to concrete and masonry for how this works.
• Poor drainage, which leaves standing water on slabs for long periods.
• Worn or missing traffic membranes and failed joint sealants.
• Thin concrete cover over the reinforcing steel, often a construction issue.
• Structural movement, especially at expansion joints and where slabs meet walls and columns.

What an inspection covers

A useful parking garage inspection looks at the structure as a system, not just the obvious cracks. Typical items include:

• Slab surfaces: cracking, scaling, spalling, exposed or rusting reinforcement, and rust staining.
• Slab soffits (undersides): spalls, efflorescence, leaks and rust stains, which often show what is happening above.
• Columns, beams and walls, with attention to the bases of columns where salty water collects.
• Traffic membranes and sealers: wear, debonding, cracking and areas worn through at drive aisles and turns.
• Expansion joints and control joints: leaking, torn seals, debris and damaged nosings.
• Drainage: blocked or broken drains, ponding, and drain pipes that leak into the level below.
• Ramps, stairs, guards and vehicle barriers.
• Building services in the garage: lighting, ventilation and carbon monoxide detection, sprinklers or standpipes, and signage.

Finding what you cannot see

Delamination is often invisible from the surface. Inspectors commonly use sounding, which means dragging a chain or tapping with a hammer and listening for a hollow sound. Hollow areas are mapped and marked. Other tools may include cover meters to check the depth of concrete over the steel, half-cell potential testing to estimate where corrosion is active, chloride testing of drilled samples, and core samples for lab testing. Our guide to concrete testing methods explains these in more detail. Before any coring or cutting, the slab should be scanned so that post-tensioning tendons, reinforcing and embedded conduit are not hit.

How a condition survey runs, step by step

A detailed condition assessment of a parkade follows a fairly standard sequence. Knowing what happens at each step helps owners plan access and read the final report.

1. Document review. The inspector gathers drawings, previous reports, repair records and any known leak locations. Record which slabs are post-tensioned, conventionally reinforced or slab-on-grade, because each behaves differently.
2. Visual survey, level by level. Every slab, soffit, column, wall and joint is walked and photographed. Record the location of each spall, crack, leak, rust stain and worn membrane on a floor plan, not just in a list, so patterns become obvious.
3. Sounding. Slabs and accessible soffits are sounded with a chain drag or hammer. Hollow areas are outlined on the floor and transferred to the plan with an approximate area.
4. Testing. Selected locations get cover meter readings, half-cell potential readings or chloride sampling. Record exactly where each test was taken so it can be repeated in future years for comparison.
5. Drainage and joints. Drains are checked for flow, and expansion joints for leaks and torn seals. Water tracks are followed to the level below.
6. Analysis and report. Findings are tied to likely causes, and repairs are grouped by urgency with rough quantities.

Areas may need to be closed off in sections while the survey runs, so plan for parking disruption and give users notice.

Typical findings and what they usually mean

How often to inspect

There is no single interval that fits every structure, and requirements can differ by province and municipality. As general practice:

• Owners or property managers should do a walk-through every spring after the salt season, looking for new spalls, leaks, blocked drains and damaged membranes.
• A more detailed condition assessment by a qualified professional is commonly done every few years, more often for older or visibly deteriorating structures.
• Any falling concrete, large new cracks, sagging or exposed corroded steel should trigger a prompt review, and the affected area should be closed off until it is assessed.

CSA S413 covers the design and repair of parking structures. Check the current edition and any provincial or municipal rules that apply to your building, and ask your structural engineer how they apply.

Maintenance that slows deterioration

Most of the damage in a parkade comes from water and salt, so most of the useful maintenance is about getting them out:

1. Wash down the slabs in spring to remove accumulated salt and grit.
2. Keep drains, trench drains and catch basins clear, and repair leaking drain lines.
3. Repair or recoat traffic membranes before they wear through, especially at turns and entrances.
4. Replace failed joint and crack sealants.
5. Repair small spalls and delaminations before they grow.

Cracks on their own are not always a concern. Our guide on when to worry about concrete cracks helps separate cosmetic cracking from cracks that need attention.

Planning repairs

A good inspection report should map the deterioration, describe its likely cause, and group repairs by urgency: items that affect safety now, repairs needed in the next year or two, and longer-term work such as membrane replacement. That lets owners and condominium boards budget and phase work level by level so parking stays partly available. For condominiums, the findings should also feed into the reserve fund study.

How ehZee can help

ehZee carries out independent inspections of parking structures, along with scanning and testing to locate reinforcement and tendons before cutting or coring. Our concrete inspections and X-ray service covers condition reviews and pre-drilling scans, and we can help you plan and coordinate the repairs that follow.

Common questions