To Leak, or Not to Leak?

By SHAWNA SMIGELSKI and ROB DAVIS
, November 2019

Your parking garage is leaking. Your dance to avoid the drips is well rehearsed and ready for the stage! Okay, the leaks aren’t that bad. But some areas on the ceiling are getting darker and the concrete is beginning to fall off…

How do we stop the water? Is that even the right question to ask?

What’s the right question to ask?

Before you can start thinking about possible solutions (even if it seems obvious!), you need to confirm the root cause of the issue – the answer to the question “What’s causing this to happen?”. It’s also good to ask, “could it lead to other issues?”, and “are we looking for a short-term solution or a long-term solution?”.

It’s not a straightforward process or decision, despite what some might have you think. We want to guide you to think critically and ask the right questions to help you select the best solution for your situation, and for your community.

So what is the root cause?

When talking about most building deterioration issues, water is a good place to start. Where is the water coming from? Water and salt will typically enter your parking garage on vehicles. Salty water and snow accumulate on cars, then it melts and drips onto your parking garage. Since concrete is a porous material, this salt-laden water can penetrate the concrete and actually alter its chemistry – leading to some bigger structural problems. Sometimes, water simply finds a crack in the concrete and will work its way through the concrete and appear as a leak on the underside of the slab.

Are the leaks just annoying, or is there something else going on?

Let’s get technical for a minute. Concrete deterioration primarily occurs due to corrosion of the embedded reinforcing steel bars (sometimes called rebar). Exposure to ‘chlorides’, typically as road salts, will catalyse the corrosion process. As steel corrodes it expands, resulting in concrete cracks and spalls we typically see in an aging parking garage. As steel continues to corrode it will lose some of its cross-sectional area, which also means it is losing its strength and may no longer perform its full structural function.

Okay, but what should we do?

This depends largely on the issue and your community. Ask yourself and your engineer:

  1. Can we afford a major repair expense, while maintaining our financial goals for the future?
  2. Is a major repair required now, or can we wait to group similar repairs together for a full rehabilitation?
  3. If we can’t afford a major long-term repair, does a temporary repair provide us with enough value? What kinds of temporary measures can we consider? What are the risks?

Sometimes a proposed solution only addresses the cosmetic portion of the issue and does not address the root cause. Imagine you remove the top of a dandelion while still leaving the root in the ground, it’s only a matter of time before it comes back! It is important to understand the purpose of the repair, how long it is expected to last, and how the root cause is being addressed before implementing the repair.

We have the option for a temporary repair, will that work?

In some cases, a temporary solution can be used to alleviate ongoing aggravations or allow you to defer major repairs by a few years while finances are arranged. A temporary solution is generally faster and less expensive than the long-term solution. It can provide short term relief for your neighbours – they don’t have to watch you dance around the drips anymore!

Temporary Repairs: This is typically used when a major restoration is not within the financial capacity of the Corporation. Deferring repairs may allow them to fall in line with other major work, saving money in the long-term. When the leak is not a major concern to the structure or presents low risk, temporary repairs should be considered. For example, drip trays (Figure 1) may be installed below cracks or expansion joints to catch water, allowing repairs to be deferred.

Okay, what about the long-term options?

Even if a temporary repair is implemented, a long-term solution will have to be planned. Remember – temporary repairs are only temporary! The main objective of any long-term repair to a parking garage is durability. You want the repair to last as long as possible to make your investment worthwhile and minimize the emotional unrest that comes with parking disruption. Some typical long-term options include:

Concrete Repairs: This option addresses the root cause of the concrete deterioration and structural concerns. Typically, localized deteriorated concrete is removed, corroded reinforcing steel is cleaned and repaired, and the concrete is replaced. This option can also allow for additional protection to be added to protect the reinforcing steel (Figure 2), including installation of an epoxy coating on the steel, or installation of galvanic anodes to act as a sacrificial component (Figure 3).

Waterproofing: A waterproofing system on the top surface of your parking garage will prevent the infiltration of water and salts. Thus, reducing the risk of leaks, reinforcing steel corrosion, and concrete cracking and spalling. The key to a properly performing system is a continuous system throughout the garage. Prevention is always better than remediation!

A waterproofing membrane will begin to wear out at the high traffic areas such as the garage ramp, garage corners, and in the upper, exposed level of a multi level garage. The high traffic areas can be repaired locally to prolong the life of the full waterproofing membrane.

Who should be involved in the repair process?

Now that you have identified a need for a repair solution to the parking garage, how can you ensure you have the right people involved in the repair process?

  1. The City: For any alterations to an existing building which affect the structural design of the building including mechanical, electrical and plumbing services a permit is required for the work to be completed. It is important that a contractor goes through the proper permitting process if a structural repair to your garage or the building in generally is to be complete.

  2. Your Engineer: Most building permits require a Professional Engineer to be involved. For large expenditures it is advisable that a Professional Engineer is involved to help with:

  • A condition assessment to correctly define the scope of work;
  • Preparing bid and specifications based on the scope of work;
  • Tendering to vetted qualified contractors; and
  • Contract management and construction review.
  1. The Contractor: Having a qualified and trustworthy contractor who has a history of completing similar work can be hard to find, but is critical to complete long-term repairs. A competitive tender process can help you get the best value for your dollar.

  2. You!: Ultimately, this is your building and your community. If something isn’t clear or doesn’t make sense, ask questions!

Remember, you can reach out to your engineer at any point during this process – they will be happy to further explain the problem, review options and ask questions alongside you, and help you make these decisions for your community. Perhaps the real question should be, are you ready to retire your dancing shoes?