About Roof Cleaning Companies
Most people don’t think about cleaning their roof until they notice something strange. Maybe there are black streaks across the shingles, green patches near the chimney, or a lot of leaves sitting up there.
From the ground, it can be hard to tell whether it’s just dirt or something that needs attention.
That’s where a roof cleaning company will help.
These companies clean roofs and remove things such as algae, moss, leaves, dirt, and other buildup. Depending on the company, they may also clean gutters or remove debris.
One thing that often confuses homeowners is the difference between algae and moss. Those black or dark streaks you see on asphalt shingles are often caused by algae, including Gloeocapsa magma.
Owens Corning says this type of algae is especially common in warm, humid areas and on roofs that don’t get much direct sunlight.
Moss is a little different. You’ll usually see it as green, thicker growth rather than flat dark staining.
It can be more concerning because moss holds moisture against the roof and, when it becomes heavy, can lift the edges of shingles.
So, should every dirty-looking roof be cleaned?
Not necessarily.
If you’re seeing a few dark streaks, the problem may mainly be cosmetic. In fact, Owens Corning says it has not seen evidence that algae deposits themselves affect the performance of asphalt shingles.
Moss and heavy organic growth are a different matter because they can hold moisture and affect the shingles over time.
That’s why a good roof cleaning company is needed to resolve all these issues.
Services offered by roof cleaning companies are:
- Roof cleaning
- Algae stain treatment
- Moss removal
- Leaf and debris removal
- Gutter cleaning
- Downspout cleaning
- Roof maintenance
- Soft washing
- Commercial roof cleaning
- Roof treatments
The cleaning method is especially important.
For example, if you have asphalt shingles, you will not consider high pressure washing ever.
GAF warns that power washing can dislodge the granules on shingles, while Owens Corning’s current 2026 guidance recommends low-pressure cleaning methods and warns against pressure washing because it can damage shingles and potentially affect warranties.
There is also the safety issue.
A roof isn’t a driveway. It’s sloped, it can become slippery when wet, and one wrong step can result in a serious injury. OSHA’s roof-work guidance emphasizes training and fall protection for workers exposed to fall hazards.
The EPA estimates that the U.S. generated about 600 million tons of construction and demolition debris in 2018, including asphalt shingles, concrete, wood, and other materials. The agency also points to recycling and reuse as ways to reduce the amount of construction waste going to disposal sites.
Our Ranking Methodology
There are plenty of companies that advertise roof cleaning. The difficult part is finding out which ones actually know what they’re doing. For our rankings, we look at practical things that matter to a homeowner rather than simply choosing companies based on how good their website looks.
1. Experience
Roof cleaning isn’t exactly the same on every roof. Asphalt shingles, tile, metal, slate, and other materials can have different care requirements. We look for companies that have experience with the type of roof they are cleaning.
2. Cleaning Methods
This is one of the biggest things we consider. For asphalt shingles, we pay attention to whether the company uses an appropriate low-pressure method instead of treating the roof like a concrete driveway.
Manufacturer guidance specifically warns against aggressive pressure washing on asphalt shingles.
3. Safety
A company can do a great cleaning job and still not be a good choice if it puts workers or your property at unnecessary risk. We look at whether the company takes roof access, fall hazards, equipment, and worker training seriously.
4. Customer Reviews
We look for comments about whether workers arrived when promised, protected the property, cleaned up afterward, communicated properly, and charged what the customer expected.
5. Roof and Moss Knowledge
We also consider whether a company understands the difference between algae, moss, dirt, and normal roof aging. That’s important because not every dark roof needs the same treatment.
6. Care for the Property
A roof cleaner is working above your house, plants, windows, siding, vehicles, and outdoor areas. We look for companies that take reasonable precautions to protect those areas during cleaning and manage runoff properly.
7. Insurance and Professional Practices
Roof work has real risks. We consider whether companies provide appropriate insurance information and follow professional safety practices.
8. Pricing and Overall Value
A company that charges a little more but uses the right method, protects your property, cleans up properly, and stands behind its work may offer better value than a cheaper company that rushes through the job.
Questions to Ask Before Hiring a Roof Cleaning Company
You don’t need to become a roofing expert before hiring someone. A few straightforward questions can tell you a lot about the company.
1. What type of roof do I have, and how will you clean it?
This is a good first question. The company should be able to identify your roofing material and explain why its cleaning method is suitable for it.
2. Will you use a pressure washer?
If you have asphalt shingles, don’t just accept a “yes” without asking more questions. High-pressure washing can remove shingle granules and damage the roof.
3. Is the black staining algae or something else?
A knowledgeable company should be able to explain what you’re seeing instead of simply calling everything “dirt.”
4. Do you remove moss or only treat it?
These aren’t always the same service. Ask exactly what the company plans to do and whether follow-up treatment is included.
5. How will you protect my plants and property?
Cleaning products, water, and roof debris can reach areas around the house. Ask how the crew protects landscaping, windows, siding, and other nearby areas.
6. Are your workers trained for roof work?
Roof cleaning involves working at height. Ask what safety equipment and procedures the crew uses.
7. Are you insured?
Ask what type of insurance the company carries and request proof if necessary. Don’t assume every contractor has the same level of coverage.
8. What exactly is included in the price?
Find out whether the quote includes gutter cleaning, debris removal, cleanup, treatments, and any follow-up work.
FAQs
There isn’t a fixed schedule that works for every home. A roof surrounded by trees or exposed to a lot of moisture and shade may develop moss and algae faster than one in a dry, sunny location. It’s better to look at the roof’s actual condition.
On asphalt shingles, dark or black streaks are often caused by algae. They’re particularly common in warm, humid areas and on roofs with limited sunlight.
Algae is often more of an appearance problem. Owens Corning says it has not seen evidence that algae deposits themselves affect asphalt shingle performance. Moss is different because it can hold moisture against the roof.
Generally, you should be very cautious about it. GAF and Owens Corning both warn that high-pressure washing can remove shingle granules and potentially damage asphalt shingles.
Usually, no. Cleaning can remove existing growth, but moss can return if the roof continues to stay damp and shaded. Keeping nearby trees trimmed and dealing with moisture issues can help.
It can if the work isn’t handled properly. Water and cleaning runoff can affect vegetation, so companies should take precautions to protect nearby plants and rinse affected areas appropriately.
That depends on the roof’s condition. Cleaning can deal with surface buildup, but it won’t fix serious problems such as widespread shingle damage, leaks, or an aging roof that needs replacement.
Don’t make your decision based only on price. Check their experience, cleaning method, insurance, reviews, safety practices, and what they include in the quote.
