Roof Washing Services: Is Soft Washing or Pressure Washing Better?
Hiring a roof washing service can dramatically improve your home’s curb appeal, but choosing the wrong method can permanently damage your shingles. As a building envelope specialist, the single most important thing I can tell you is this: Not all roof cleaning services are the same. This guide will explain the critical difference between soft washing and pressure washing, and show you how to hire a professional who will protect, not harm, your roof.
Key Takeaways
- Soft Washing is the Standard: For most residential roofs, especially asphalt shingles, low-pressure soft washing is the only safe and recommended cleaning method.
- Pressure Washing is High-Risk: High-pressure washing can strip protective granules from shingles, voiding your warranty and shortening the roof’s lifespan.
- Cost is By Square Foot: Expect to pay between $0.20 and $0.60 per square foot for a professional roof soft washing service.
- Vetting is Crucial: Always verify a contractor’s insurance, cleaning method, and property protection plan before hiring.
The Key Battle: Soft Washing vs. Pressure Washing
Understanding the difference between these two methods is the most important step in protecting your investment. They are fundamentally different, and using the wrong one has serious consequences.
| Method | How It Works | Best For |
|---|---|---|
| **Soft Washing (Recommended)** | Uses low pressure—similar to a garden hose—to apply a specialized cleaning solution that kills algae, moss, and lichen at the root. | The *only* safe method for asphalt shingle roofs. Also ideal for tile, slate, and metal roofs. |
| **Pressure Washing (High Risk)** | Relies on high-pressure water jets to blast away surface growth. Does not kill the root of the organism. | Extremely limited use. Potentially for unpainted concrete or metal surfaces by a highly experienced pro, but **never** on asphalt shingles. |
Using a high-pressure washer on an asphalt shingle roof can strip away its protective granules. These granules are essential for protecting the shingle from UV rays and weather. Once they’re gone, the roof’s lifespan is drastically reduced, and your manufacturer’s warranty will be voided. The high pressure can also force water up underneath the shingles, leading to leaks and rot.
How Much Does Roof Washing Cost?
The cost of professional roof cleaning services is a worthwhile investment to protect your home’s value and prevent damage from organic growth.
Typical Roof Soft Washing Cost
This is the typical price range for a professional, insured company using the correct soft washing technique. The final cost depends on the factors below.
Cost factors:
- Roof Size (total square footage)
- Severity of Growth (heavy moss is more expensive)
- Roof Pitch (steeper roofs require more safety gear)
- Property Accessibility & Height (two-story homes cost more)
Example: Cost for a 2,000 sq. ft. Roof
To put this in perspective, for a typical 2,000 sq. ft. roof, you can expect a total professional soft washing cost of $400 to $1,200, with most homeowners paying around $800.
Hiring Checklist for a Roof Washing Pro
Asking the right questions upfront will help you filter out unqualified operators and find a true professional.
Vetting Your Roof Cleaning Service
“The runoff from a roof cleaning can be a real threat to a carefully curated garden. Even biodegradable cleaners can harm certain delicate plants if not properly managed. A professional service should always pre-rinse all vegetation, cover sensitive areas, and have a system for diverting or diluting the runoff. It’s a sign of a truly professional and considerate crew.”
