1. Planning & Assessment (Before Any Water Flows)

Industrial roof cleaning starts before equipment is turned on.

Identify roof type: Metal, membrane (TPO, EPDM, PVC), concrete, or coated systems all have different pressure limits.

Inspect condition: Look for loose fasteners, damaged seams, corrosion, brittle membranes, or existing leaks.

Check slope & drainage: Prevent standing water and interior leaks.

Environmental controls: Note nearby air intakes, skylights, solar panels, or sensitive equipment.

Local regulations: Wastewater runoff may need containment or filtration.

👉 This step determines pressure level, nozzle choice, and cleaning method.

2. Safety Setup (Critical for Industrial Jobs)

Roof pressure washing is high-risk work.

Fall protection (harnesses, anchor points, guardrails)

Non-slip footwear

Electrical hazard awareness (overhead lines, rooftop units)

Barricades/signage below the work area

PPE: eye protection, gloves, hearing protection

Many industrial jobs require a job safety analysis (JSA) before starting.

3. Equipment Selection

Typical setup includes:

Pressure washer:

Usually 1,500–3,000 PSI (often lower for membranes)

Hot water units may be used for grease or oil

Nozzles:

Wide-angle fan tips (25°–40°)

Never zero-degree tips on roofing

Surface cleaner or soft-wash attachment (common for membranes)

Low-pressure chemical sprayer for detergents or biocides

4. Pre-Treatment (Softening Contaminants)

Instead of blasting immediately:

Apply a roof-safe detergent or biocide at low pressure

Targets:

Dirt and soot

Mold, algae, lichen

Bird droppings or industrial fallout

Let solution dwell (usually 5–15 minutes, not allowed to dry)

This reduces the need for high pressure, which protects the roof.

5. Pressure Washing Technique

This is where technique matters more than raw power.

Start from the highest point and work downward

Keep the nozzle:

At a shallow angle

A consistent distance from the surface

Use overlapping passes for even cleaning

Avoid spraying:

Directly into seams, fasteners, or penetrations

Under flashing or membrane edges

For membrane roofs, pressure is often kept low enough that the process is closer to a controlled rinse than aggressive washing.

6. Rinsing & Runoff Control

After contaminants are removed:

Thoroughly rinse detergent residues

Ensure drains are clear and flowing

Capture or filter runoff if required (especially near storm drains)

This prevents chemical damage and regulatory issues.

7. Post-Cleaning Inspection

Once dry:

Inspect seams, coatings, and fasteners

Look for newly exposed damage

Document condition (often with photos)

Recommend repairs or recoating if needed

Many industrial facilities use this step to support preventive maintenance programs.

Key Takeaways

Industrial roof cleaning is controlled, methodical, and safety-driven

High pressure is rarely the goal—correct chemistry + technique is

Wrong pressure or nozzle choice can cause leaks or void warranties