What Should You Ask a Roof Cleaning Company Before Booking?
Ask whether they soft-wash or pressure wash, whether their insurance specifically covers roof work, how they protect landscaping from chemical runoff, and what their lichen protocol includes. Soft-wash only is the correct answer for asphalt, and a legitimate soft-wash company describes its 12-volt pump system and downstream chemical injector rather than a pressure washer.
Do You Use Soft Washing or Pressure Washing?
The correct answer for asphalt shingles is soft washing. High-pressure washing damages asphalt shingles by removing the granule coating that protects the asphalt layer from UV degradation. If the company says they use pressure washing on shingles: do not proceed. Follow up by asking the PSI and application method a legitimate soft-wash company describes their 12-volt pump system and downstream chemical injector, not a pressure washer.
Are You Insured for Roof Work Specifically?
Ask for a certificate of insurance and confirm that the policy covers work on rooftops. Some general liability policies exclude work above a certain height or exclude roofing-related work. Ask specifically: does your liability policy cover work performed on rooftops? Does your workers’ compensation coverage apply while your crew is on my roof? Both must be confirmed, not assumed.
How Do You Handle Landscaping Protection?
Sodium hypochlorite runoff from roof cleaning can damage or kill plants. Ask for a specific description: do you pre-wet plants before applying solution? Do you use directed spray to avoid plantings? Do you rinse the landscape area after cleaning? A vague answer (‘it’s diluted’) is not an adequate protocol for protecting established landscape plantings.
What Is Your Protocol for Lichen?
If your roof has lichen, ask: is a follow-up visit needed after die-off, and is that included in the price? Lichen does not immediately release after chemical treatment the follow-up to physically remove dead lichen after the kill pass is sometimes needed. Understanding whether the quote includes this follow-up prevents surprise charges later.
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
Roof Cleaning Cost at a Glance
Roof size: Larger roofs cost more due to more area to clean.
Roof pitch: Steeper roofs cost more for special equipment and safety measures.
Growth severity: Heavy moss, algae, or lichen means more work and higher cost.
Overall range: $300 to $600, averaging $450.
Ranges here are national ballpark figures, not quotes. Actual pricing varies by region, home condition, materials, and contractor. How we source cost data.