Blog PostApril 15, 2021 - Educational
Waterproofing: Protecting Parking Garages
Are you doing all you can to minimize your parking garage maintenance costs? Parking garages are continually exposed to corrosive environments leading to deterioration, resulting in the need for engineering evaluations, localized repairs, and/or wholesale rehabilitation. Stakeholders involved in the design, operation, maintenance, and restoration of parking garages need to understand the role and importance of waterproofing systems in protecting these structures. When waterproofing systems are not given adequate consideration, garage repair and maintenance costs increase and the anticipated service life decreases.
Concrete and its reinforcing steel do not like water and salt. The long-term performance and service life of parking garages is directly related to the effectiveness of the waterproofing systems utilized to prevent moisture and de-icing salt contamination. By effectively protecting the structure and maintaining the waterproofing system in a state of good repair, owners can slow down the rate of deterioration and allow for safe, uninterrupted use of the parking garage. The structure’s protection also increases the duration between large rehabilitation projects, reducing the burden on your reserve fund.
On the other hand, the failure of waterproofing systems often results in economic losses, including damage to property (i.e. vehicles, equipment, etc.), hazards like loose concrete, and expensive structural repair costs. A functional waterproofing system is, therefore, the front line of defence for any structure subjected to water and de-icing salts.
Designing the System
Selecting the right waterproofing system is a challenge that is unique to the structure, the condominium corporation’s needs, and site conditions. Waterproofing systems are broadly grouped into two categories—thin and thick systems. These groups have various subcategories within them comprising different materials, properties, and performances. A factor not to be overlooked is initial installation cost, as a waterproofing system must be cost effective. Proper selection requires a thorough understanding of available products and their performance characteristics.
Thin Waterproofing Systems
In general, thin systems are typically polyurethane based and are liquid applied with squeegees and rollers. They are comparatively thin (1.5 to 3 mm) and lightweight. Thin waterproofing systems are ideal candidates when installing a new waterproofing system on a previously unprotected concrete structure that was not originally designed to carry the loads associated with a thick waterproofing system.
Thick Waterproofing Systems
Asphaltic waterproofing is typically considered a “thick system” as the finished assemblies range from 20mm to over 150mm in thickness. These systems consist of a rubberized asphalt waterproofing membrane overlaid with a wearing surface (e.g. asphalt, concrete, interlocking pavers, etc.). The wearing surfaces associated with thick waterproofing systems are generally more durable and resistant to impact damage than thin systems. As such, thick waterproofing systems are ideal candidates for open parking and podium decks exposed to the elements where snow removal is required.
The long-term performance and service life of parking garages is directly related to the effectiveness of the waterproofing systems and their maintenance. Regular inspection and maintenance of your waterproofing systems will reduce the need for costly structural repairs to your parking garage structure and reduce the overall burden to your reserve fund. Speak to your engineer about your options and minimize your parking garage maintenance costs.
Ben Kraemer, P.Eng.
Project Engineer (Building Science and Restoration)