Underground garages face the same dirty issues as surface lots and then some.
Below-grade parkades often have poor ventilation, resulting in stale and stagnant air. This intensifies odours from trash, urine, cigarette butts, vehicle fluid leaks and rainwater, which is regularly tracked in and takes longer to evaporate than on surface lots. Dirty water also sits in floor drains and catch basins, contributing to undesirable underground garage smells. Because these parkades aren’t exposed to the elements, rain doesn’t wash away salt residue. Salt is corrosive to steel rebar — the backbone of all parking garages — and the membrane system installed to protect against water ingress.
Pressure washing removes the tough stuff — excess salt, compacted dirt buildup and vehicle fluid stains — leaving the garage in pristine condition. It’s employed after sweeping and any oil stains or heavily soiled areas have been pre-treated with specially formulated products. Parking facilities should be pressure washed at least once per year, typically post-winter, to keep the garage clean and to maintain the integrity of the structure.