Sherlock Roof Cleaning
Roof & Exterior Cleaning
(336) 346-8682
Greensboro, North Carolina, 27408 USA


Most frequently asked questions – answered.

Greensboro, NC 27408
(336) 346-8682
Mon-Fri: 8:00 - 5:00

Our Affiliations

Doug Ruckers Pressure Cleaning School










Frequently Asked questions About Our Services – Answered

What are those ugly black streaks on my roof?

Remember, what looks OLD might just be MOLD! Your roof is not’s infested with mold, algae, & bacteria! (read further if you are a nerd like me that need the scientific explanation)

Your roof’s unsightly black streaks are mostly made up of a form of bacteria, thriving and feasting on your roofing surfaces. The bacteria’s scientific name is “Gloeocapsa Magma”, GM for short.  The bacteria spores spread by air, the micro-organisms feed off of moisture, and the limestone fillers found in shingles. Typically found on the north and north east sides of roofs which receive less sun,  and the shady areas that tend to stay wet longer caused by overhanging tree branches.  Accumulation of the bacteria starts to show as the ugly black streaks on your roof. The bacteria turns black as their outer coating turns hard to protect itself against the suns UV rays. As the bacteria colony grows, it lengthens and streaks down the roof caused by gravity, and holds more moisture on the roof, accelerating the bacteria growth.  This provides an excellent environment for moss and lichen to soon follow! It is a vicious circle of roof destruction, decay and dramatic drop in your home, or business’s curb appeal.  The earlier your roof is cleaned and treated the better!  Wash Pros will stop the damage in its tracks! Do not wait until moss, lichen and algae also appear and take over your roof!

What Causes Roof Stains and Other Roof Issues?

For the last 30 years or so, asphalt shingles have been manufactured using limestone as the base filler for added weight and to cut the expense of manufacturing. The ugly black streaks are a form of bacteria (Gloeocapsa Magma) that feeds off of the limestone filler of your shingles! The materials of most asphalt shingles encourages the bacteria and algae to grow. The longer the black streaks remain and grow, the more damage is done to your shingles. Roof & Exterior Cleaning will stop the damage in its tracks and help extend the life of your roof!

Can the bacteria, algae, moss and/or lichen on my roof cause damage?

Yes! Un-treated roofs may lose up to 50% of the expected roof shingle life cycle. The black streaks (bacteria) are eating the limestone in the shingle and causing erosion. Roof bacteria, moss, lichen and algae all cause granular loss from shingles. The bacteria weaken the shingle, the fiber root systems moss and lichen cause discoloration, and can cause small cracks in shingles. The resulting damage will lessen the life cycle of the roof. Granular loss also reduces reflection of the suns UV rays and protection from the elements.

Is cleaning my roof merely a cosmetic repair?

NO. The black streaks will prevent your shingles from deflecting the sun properly and can increase your cooling costs. Also, since the algae is feeding on the limestone in your shingles, it is slowly breaking them down. By not cleaning your roof, you are reducing the life of your shingles by up to 50%!

Will you damage my roof with high pressure?

NO. We do not use a pressure washer at all when cleaning roofs. We use a specialized LOW/NO PRESSURE system designed to gently clean the algae from the surface of your roof. Our system uses no more pressure than your garden hose! We simply apply the cleaner; allow it to dwell and rinse it clean.

How would you clean my roof, siding, fencing and other exterior surfaces?

Sherlock Roof Cleaning technicians have been trained to use soft wash cleaning (LOW/NO pressure) and treatment process involving the use of professional grade, low/no pressure applications of the proprietary soft wash cleaning solutions.  Each exterior surface to be treated is analyzed to determine the best mixology and is specifically formulated for the task at hand.  This process maximizes the cleaning and treatment value, while keeping costs to the lowest levels possible.

We will not use a pressure washer on your roof or siding!  Our soft wash process is the system recommended by ARMA (Asphalt Roofing Manufacturers Association) and GAF (North America’s largest shingle manufacturer), and is safe for your home, family, pets, and any adjacent landscaping.  

What type of pressure do you use on my roof and siding? Garden hose pressure!

First, we will never use a pressure washer or high pressure on your roof or siding. Our professional grade system is designed to operate and deliver the application of cleaning solutions at a very low pressure… approximately 45 -50 psi! That’s about the strength of your garden hose or a hard rain fall. Our solutions do the work, gently and as recommended by roofing manufacturers.

Will the cleaners being used damage my plants, people or pets?

Specific plant and property protection training has been completed and protective measures are part of our everyday operating procedures!  People, plants and pets remain safe!  All of our solutions are eco-friendly and bio-degradable. We ask that pets and their families stay indoors until the job is complete. Certainly we understand people need to come and go. This is accomplished with just a little coordination in the work area. Pets are free to go outside once the job is complete and worksite cleaned up.

Our crew is trained to do everything within our power to protect plant and property! We pre-wet all nearby plants and vegetation as a precaution, then continue as needed during the cleaning and treatment just to be extra protective to your plant beds. We take plant protection one step further and apply a proprietary plant wash containing plant nutrients, a chemical neutralizer and apply to all nearby plants and vegetation as an added precaution once the job is complete! This plant wash and rinse is specially formulated to mitigate any potential concerns. Some customers say this is the first time in a long time their plants have been fertilized, watered and treated so well!

We take every foreseeable precaution to insure that your landscaping and personnel property are protected and remain in the same condition or better than when we arrived at your site.

Why clean my roof before the winter? Isn’t it just going to get dirty again?

The black streaks on your roof are not dirt. They are caused by living organisms – algae, bacteria, mold, mildew, etc. The roof stays damp and is an ideal breeding ground for these organisms to thrive. Our process eliminates these organisms.

Do you walk on the roof?

95% of the time all of our roof cleaning and treatment work can be done from the gutter line using ladders, or even from the ground!

Does my roof cleaning come with any type of guarantee?

Yes.  Our Sherlock Roof Cleaning proven process and proprietary solutions are guaranteed to successfully remove the ugly black streaks from your roof the day of cleaning and treatment. Our Sherlock process provides a 100% kill ration on bacteria, algae, moss and lichen and inhibits the return of all growth! We are so confident in our process and methods that we provide a 5-year Sherlock “No Grow” Guarantee with every complete roof cleaning!

Do you do partial cleaning on just the bad areas?

Yes, we can. Sherlock Roof Cleaning understands that certain cleaning needs may apply, such as touching up only the front visible roof to increase the curb appeal for a home for sale.  But it is highly recommended to avoid a partial cleaning and treatment.  The un-treated sections most likely already have bacteria and algae spores you cannot see. These spores will travel to the treated roof sections and expedite contamination and re-growth. Therefore we do not offer the 5-year Sherlock “No Grow” Guarantee or the “Make It Pop!” package transferable warranty on partial cleanings and treatments.  Our 5-year Sherlock “No Grow” Guarantee is transferable if a home is sold.

How soon after a roof cleaning do the algae streaks return?

Whole roof cleanings come with a 5-year Sherlock “No Grow” Guarantee but you can generally expect the roof to stay clean and beautiful for at least three to five years before the algae becomes noticeable again. Every situation is a little bit different, and it’s not unusual for a roof to stay clean for five years or more after a professional non-pressure cleaning.  The 5-year Sherlock “No Grow” Guarantee guarantee is transferable in the event that you sell your home.

Partial roof cleanings are not recommended and DO NOT come with a guarantee.  It’s important to understand that roof algae is not visible to the naked eye in its early stages, so while you may not see it in some areas, it’s most likely already there and beginning to develop.  The growth of algae is slowed in areas that receive maximum sunlight, but eventually it will become visible!  That’s why it’s so important to treat the entire roof surface.


Are you trained, hold certification and insured?

Yes,Sherlock Roof Cleaning employees have completed certification training through Doug Ruckers’s Power Washing School, attend hands on seminars and attend yearly industry training events provided by the UAMCC to stay current on all equipment, techniques, methods and application methods. Sherlock Roof Cleaning carries a $1 Million Commercial Liability Policy for your added protection and peace of mind.

Do I have to be home for the estimate or during the cleaning?

No. We can inspect your roof and leave a written estimate on your front door if you’re not home or simply give you a call back. You don’t have to be home for the cleaning either, but before you leave please bring pets inside, make sure all doors and windows are closed securely, unlock any gates, and move your vehicles into the garage or out to the street. We will need to use your exterior water spigots during the process, so please make sure that we’ll have access to them.

How much does roof cleaning cost?

Each roof cleaning job is different, and many factors are taken into consideration when developing a quote. Pitch of the roof, square footage, degree of black stains, is moss and/or lichen present, perimeter landscaping, accessibility, water spigot pressure, etc. 

Beware of the lowest bidder! Sherlock Roof Cleaning may not be the lowest bid, but will always be the company that provides the highest level of value, service and professionalism to the customer.  We are not satisfied until you are satisfied.  We provide free, prompt, no-hassle written estimates, so please call us or send a message through our contact form.

What kind of neighborhood rates do you offer?

Working with neighbors will benefit you greatly in terms of discounts. We offer up to hundreds of dollars off each home on multi-home neighborhood discounts.

What do you offer that other roof cleaning companies don’t?

Sherlock Roof Cleaning is a company devoted to providing its customers the highest level of quality, value, professionalism and customer service. We will treat you, your home and property with respect and as if it were our own. We will not rush to complete a job, or cut corners to save time. Sherlock Roof Cleaning prides itself on spending as much time as necessary to ensure that a high level of value is provided and your 100% level of satisfaction is achieved.

We invite comparison to other roof and exterior cleaning companies.  Do they have proof of $1 million dollar commercial liability insurance? Do they carry the (expensive but necessary) appropriate Workers Compensation insurance to protect their employees and the homeowner? Have they invested in professional grade equipment? Have they sought out and attained certifications in the soft wash field or roof and exterior surface cleaning? Are their personnel uniformed, clean-cut, and have cleared background checks?

We provide safe, proven soft wash methods, utilize professional grade equipment, use exclusively low-pressure soft wash methods on roofs and siding, and non-damaging, eco-friendly, bio-degradable cleaning solutions for your exterior home cleaning needs.  We are trained and specialize in the cleaning and treatment of roofs and siding. We are dedicated to earn your good referral, earn your respect and the opportunity to serve all of your exterior surface cleaning needs.

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