Case Study · Hot-Water Pressure Wash · Parking Structure
Rady Children's Hospital, parking garage restoration
A multi-level parking structure serving thousands of vehicles, patients, and visitors every week at one of San Diego's busiest pediatric medical campuses. Gum, oil, and accumulated grime lifted off the concrete with hot-water pressure washing — executed overnight and across a continuous weekend shift so the garage stayed available every clinical hour.
The work in motion
Watch the transformation
Equipment, technique, and the before-and-after across the structure. Hit play to load the video — until then it's just a poster image, no YouTube payload.
Why this job mattered
A high-traffic medical facility — appearance and sanitation count
A parking structure that serves thousands of vehicles, patients, staff, and visitors every week is not a standard pressure-washing job. In a healthcare environment the goal isn't only aesthetics — it's helping maintain a cleaner, safer environment for the families and visitors entering the hospital.
What a hospital parking garage accumulates over time:
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Embedded gum
Across walkways, curbs, and ramp aprons.
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Motor oil + transmission fluid
Drips and stains at every parking stall.
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Tire residue + roadway grime
Tracked in from the street on every vehicle.
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Food + beverage spills
Across pedestrian zones and approach paths.
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Dirt + dust
Tracked in from vehicles, settled across the deck.
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Organic buildup
Algae and mildew in corners, stairwells, and low-traffic edges.
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Odor accumulation
Around floor drains and pedestrian areas.
The scope
What the job actually included
Parking-structure work isn't one task — it's a stack of them running in sequence on the same surface. Each contaminant category wants its own combination of pressure, temperature, and dwell time to lift cleanly.
The work, per surface category:
- Hot-water pressure washing on the deck concrete. Heat is what makes the difference on petroleum-based staining — cold water lifts surface grime, hot water dissolves the binder underneath so the stain releases instead of smearing.
- Gum removal on sidewalks, curbs, and ramp aprons. Dedicated steam-based gum removal equipment, not a wand-and-prayer approach. Gum binders soften at specific temperatures; the right tool gets the residue up without etching the concrete around it.
- Oil and transmission-fluid stain treatment at parking stalls. Surface degreaser pre-treatment, dwell, then hot rinse with recovery.
- Commercial sanitization passes on pedestrian zones — walkways, elevator lobbies, stairwell landings, and high-touch areas inside the structure. EPA-registered disinfectants, dwell times documented.
- EPA-compliant wastewater recovery on every surface treated. Runoff captured at point-of-use rather than allowed to enter the storm drain. Storm-drain liability stays where it belongs.
Why hot water
Concrete is a pressure job. Hot-water is what actually lifts the petroleum.
Painted stucco and EIFS get soft-washed — chemistry, not pressure, because the substrate is delicate. Concrete is the opposite case. The substrate can absolutely take the pressure; the question is whether the pressure alone moves the stain. For oil, transmission fluid, gum, and tire rubber, cold pressure mostly redistributes the staining rather than lifting it.
Hot-water pressure washing solves that. Industrial hot-water units run at temperatures that soften the petroleum binder so the stain releases. Combined with the right pressure and a recovery system catching the runoff, the deck comes back to a clean concrete color rather than a wet version of the same staining pattern.
The investment in hot-water-capable equipment is one of the things that separates a contractor with a Home Depot rig from a commercial outfit. We made that investment specifically because parking-structure work and dumpster-pad work — the highest-volume, dirtiest concrete jobs we do — don't yield to cold water in any reasonable amount of time.
The hospital constraint
Continuous operations, overnight scheduling, EPA discipline
A hospital parking structure doesn't have downtime. Patient families arrive at all hours. Overnight admissions, shift changes, and emergency arrivals don't pause for facility work. Closing the deck for a daytime project wasn't on the table.
The project required coordination across several constraints:
- Multi-level structure access — production cleaning across multiple decks of the garage.
- Overnight scheduling — crews mobilizing after low-traffic hours, clearing out before the morning shift change.
- Continuous weekend operation — multi-day execution so the structure stayed available during clinical hours.
- Water access logistics — coordinating fill points and runoff capture across multiple levels.
- Wastewater recovery compliance — runoff captured at point-of-use rather than released to the storm drain.
- Pedestrian and vehicle traffic — work zones managed around continuous facility access.
- Tight turnaround — restored, available, and dry for the next clinical hour.
We treat hospital work as a separate practice from general commercial cleaning. Commercial Cleaning of San Diego, Inc. is a member of the California Society for Healthcare Engineering (opens in new tab) — the statewide trade association for healthcare facility engineers and approved vendors, affiliated with ASHE under the American Hospital Association. See the membership details on our About page for what that connection means operationally.
Client reference
From the Plant Operations & Maintenance manager
Roy Robinson's reference letter, written following our prior soft-wash exterior project at the hospital — the engagement that established the working relationship behind this parking-structure work.
Client quote
"This letter serves as a reference for Joseph Dufresne and his team at Commercial Cleaning of San Diego, Inc. They completed an exterior soft washing project at Rady Children's Hospital with professionalism, attention to detail, and a clear understanding of the needs of a healthcare facility."
"The work was completed safely, thoroughly, and with full regard for patient safety and hospital operations. We were pleased with the outcome and would not hesitate to work with them again or recommend their services."
Property managers — this scales beyond hospitals
Large parking structures need more than cosmetic cleaning. Regular maintenance preserves the appearance of the property, improves visitor perception, reduces slip hazards, and prevents long-term buildup that becomes increasingly difficult and expensive to remove.
Hot-water pressure washing, gum removal, oil-stain treatment, and EPA-compliant wastewater recovery — quoted around your operational windows, executed overnight when your tenants can't spare the daytime closure.