A guide to condo parking garage maintenance
Corporations can maximize their return on investment by preserving
By Michael Pond
03 March 2015
Data suggests that a condominium corporation should expect to spend
between $100 and $500 per parking stall per year in order to keep its
parking garage in good working order and build up savings for long-term
renewal of the garage’s moisture protection systems. That’s the
equivalent of $15,000 to $75,000 per year — or $8 to $42 per month per
stall — for a building with 150 parking stalls. So, where should that
money be spent and how does a corporation maximize its return on
What follows are ways in which a condominium board and property manager
can best spend the operating budget and reserve fund on parking garage
maintenance and repair and on that of the associated
But first, here’s a very basic chemistry and physics lesson:
The reinforced concrete parking structure is the most common type of
parking facility in use today. Its durability is influenced greatly by
the effectiveness of the waterproofing system(s) used to protect it
from moisture and chlorides. There are several ways in which these two
elements attack and damage reinforced concrete.
Reinforced concrete deteriorates when hydrogen dioxide (water) and
calcium chloride (salt) come into contact with a ferrous metal
(iron-based alloy) such as carbon steel and forms iron oxide (rust).
The iron oxide occupies a greater volume of space than the original
metal alloy, thereby exerting an expansive pressure on the concrete
surrounding the steel.
In reinforced parking structures, carbon steel is generally found in the
embedded reinforcing steel or rebar. Concrete has excellent compressive
strength characteristics but very poor tensile strength
characteristics. So the expansion of the rust results in the concrete
delaminating from the embedded reinforcing steel, thus reducing the
effective depth of the slab at the delamination location and thus the
structural or load-carrying capacity of the suspended parking deck. If
left unchecked, ongoing corrosion-related deterioration could
eventually lead to significant structural integrity concerns, including
eventual partial or total collapse of the parking structure.
As may be apparent, the goal of parking structure maintenance and
protection is to limit the extent to which the parking structure
deteriorates and is exposed to moisture and chloride attack. Limit the
deterioration and exposure in order to limit the cost of repairing the
The waterproofing industry has a wide spectrum of moisture mitigation
and protection systems that can assist in limiting or slowing the rate
of deterioration caused by moisture and chlorides. Traffic deck
coatings, expansion joint glands, joint and crack sealants, cathodic
protection, penetrating sealers, and corrosion inhibitors are only a
few of the systems available.
Engineers and architects can play their part as well, by designing
durable parking structures. They balance construction cost premiums
with material thicknesses, depth of concrete cover over rebar, drainage
slopes, and high-quality concrete-mix designs.
So while the design of parking structures is essentially a fixed and
unchangeable constraint, waterproofing systems can be effectively
managed. A comprehensive approach involves annual maintenance and
operating programs as well as periodic capital renewal projects,
including the repair and replacement of the moisture protection systems.
Consider the following measures and strategies to maintain the
performance of a waterproofing system and mitigate the deterioration of
a parking garage structure:
Flush and clean the floor drains and drain pipes in a parking garage at
least twice a year. This allows salt-laden water brought in by vehicles
to be quickly discharged from the surface of the parking deck to the
storm or sanitary drainage system. Cleanouts should also be installed
on the underside of the slab, and drain bodies should include operable
grates and removable sediment buckets for easy cleaning. Also power
wash the entire parking deck. Removing crystalized salts from the deck
mitigates chloride contamination of the concrete.
Perform annual inspections of the moisture protection systems. Make
note of leaks on the underside of the slab, excessive wear in the
traffic deck coating, tears or adhesive failures of the joint sealants,
or signs of standing water around drains. Hire a contractor to
periodically repair any observed defects.
Limit the use of sodium chloride, calcium chloride and magnesium
chloride as a de-icing salt for snow melting. These types of salts have
particularly deleterious properties that accelerate deterioration of
reinforced concrete structures. Consider using calcium magnesium
acetate, potassium acetate, urea, or sand instead.
Hire qualified companies to undertake a detailed condition assessment
of a parking garage’s structure and moisture-protection systems.
Experienced and qualified firms have the resources and the tools to
assess and identify non-visual structural deficiencies as well as
establish the current condition of the waterproofing system and its
anticipated remaining service life. Invite them to review a garage on a
three-year cycle. Do not rely solely on the reserve fund study to
establish replacement timelines for a garage’s moisture-protection
systems. Detailed assessments are required to gather the pertinent
Plan to implement a targeted or localized rehabilitation program of the
moisture protection systems at least once prior to full system
replacement. Allocate money from the reserve fund to overcoat drive
lanes, locally repair the traffic deck coating, replace damaged or
clogged drains, and refresh the garage in order to realize the full
service life of its waterproofing system.
Replace the moisture-protection systems before the salts and moisture
can erode the integrity of the underlying structure. It’s a fallacy
that if the levels of concrete deterioration are low, then the moisture
protection system doesn’t need to be replaced. Waterproofing systems
can appear to be in good shape, but they may have lost their ability to
resist the penetration of salt-laden water. Once chlorides
penetrate the thin layer of concrete that protects the embedded
reinforcing steel, they are very difficult to remove and will only
increase in concentration, and therefore destructive capabilities, as
the structure ages.
In the end, a corporation’s reserve fund makes the financial
contingencies required to maintain the value of its capital assets and
allows owners to live their lives in a comfortable and secure
environment. It can be an unnerving experience to wonder whether a
corporation’s reserve fund is adequately funded for inevitable future
repairs and renewals, and how its asset will be viewed by prospective
buyers when owners are ready to sell their units. Do not spend it on
large structural repair programs in the parking garage; rather,
maintain the moisture protection systems and take heed from those with
the experience and resources to help a corporation plan for the future.
Michael is a principal at Read Jones Christoffersen Ltd., a national
consulting engineering firm located in all major markets across the
country. He is a licensed professional engineer specializing in the
rehabilitation of existing buildings. He can be contacted by phone
(647-792-0781) or email (firstname.lastname@example.org).
top contents appendices