Foxland Blog

Roof Cleaning: The Ultimate Guide

Blog Category: Roof Cleaning

Have you noticed black stains on the roof or possibly moss on the roof shingles? Then you need to read this article or find a roof cleaning service in your area.

What are the Black Streaks on Your Roof?

Might I begin by explaining why those black streaks are there? Organic material is in the air all around us, and it lands on your roof. A fungal growth called blue-green algae will attach itself to that organic material to eat it and once its food supply is gone, it will die which causes the black streaks. The algae itself is not an issue, seeing as it does not grow roots in your shingles.

However, the issue comes when other fungal growths such as mold, mildew, and moss feed upon the dead algae and organic matter. These types of fungus have roots and will anchor themselves on your roof, causing your roof to deteriorate prematurely. Therefore, removing the black streaks from your home is so important.             

Equipment for Roof Cleaning

Soft Wash Pumps

12-volt Air Diaphragm Pump

Professionals use soft wash pumps to apply the solution and in a quick amount of time doing no damage to the shingles. A 12-volt diaphragm pump is the most common due to it being cheaper than an air-driven pump.

Air Pump

The air pump sprayers are becoming more popular for the higher gallons per minute the air compressor allows. The downside of this is the cost, and while some don’t see us as a downside, I do. The higher gallons per minute. I say that because of the amount of solution that can be wasted with a higher GPM. Which will end up in the landscaping or splashing onto the siding.

Pump up Sprayer

If you are on a budget or just a homeowner and don’t want the expense, have a $1,200 soft wash pump. You can use a handheld or backpack pump sprayer to do the same job. If this will be a onetime clean, my advice just using a 2-gallon pump sprayer which can be bought at Home Depot for about $30. Or if you’re the person who likes all the cool stuff in life Echo makes an amazing backpack sprayer it’ll make the job a lot faster for $100.

ECHO 2 Gal. Sprayer
ECHO 4 Gal. Internal Piston-Pump Back Pack Sprayer


Obvious as this is, I see people soft washing roofs repeatedly without this vital piece of PPE. The respirator to use is a half or full face mask with P-100 filters.

Chemicals for Roof Cleaning

Never Use


Tri-sodium phosphate or TSP has been used by pressure washing companies starting back in the 1970s. However, as the pressure washing industry grew and scientists started turning their attention more towards the cleaning industry, pressure washers stopped using tsp in the late 1990s. Pressure washers stopped using this product not because it didn’t work, it works extremely well. Yet, the problem with TSP is that it’s will deglaze glass on Windows.

Ok to Use


We want to use soap to aid bleach, to better adhere to the roof for a longer time. Soap is a surfactant which also allows it to attract dirt and organic particles present on the roof. For onetime use, most dish soaps will work but don’t use Dawn. Dawn breaks bleach down, forming light form of mustard gas. If the solution is to be stored, use a surfactant made to be added in bleach like Elemonator. For dish soap only use 2 oz. per gallon.


As we have learned, algae cause the black streaks or perhaps you have some Moss or mildew on the roof. whichever these are bleach will kill off any of these fungal groups allowing it to be removed from your shingles.

Where to Buy Bleach

When evaluating where to buy bleach, you can purchase this from three main sources. Big-box stores such as Walmart or Home Depot, a pool supply company, and pressure washing distributers. The two factors to look for in your purchase are price per gallon and the percentage of sodium hypochlorite, the main ingredient.

The big box stores sell bleach with sodium hypochlorite between 6%-8% and the price per gallon averages $5.50. Pool supply stores sell bleach with the main ingredient at 10% and the price per gallon is also $5.50. However, most pressure washing distributors sell bleach with sodium hypochlorite at 12.5% and the price per gallon is between $1.50 and $2.50. Unfortunately, the distributors only sell in 5-gallon amounts, not 1 gallon. From this we can take the best place to buy bleach is a pressure washing distributor, then pool supply store, and the worst is a big box store.

Store Comparison

Dilution Rates for Roof Cleaning

When looking online you will see a lot of Articles and chat forums speaking of diluting solution 50% for roof treatments. While others say you have to use 12% sodium hypochlorite to remove the stains. I would like a breakdown of all the different percentages of sodium hypochlorite and how they react with the roof.

Treatment 3%-4.5%

Roof cleaning companies and roofing manufacturers, like GAF the largest roofing manufacturer, recommend using 3% to 4.5% sodium hypochlorite to treat the fungal growth. This percentage will kill the growth however not remove it. Because we do not want to put a significant amount of water on the roof to pressure wash it off will allow the rain to take care of that for us after one heavy rain or two medium rings with the gross dead it will be removed from your roof.

Immediate results 6% to 12.5%

For immediate results, some pressure washers especially down in Florida and Southern California will use 6% even up to 12% sodium hypochlorite. This kills the fungus. Yet the solution may not remain on the roof and must be rinsed off. Well, they do not pressure wash the solution off; they use a soft washing machine or I have removed even a garden hose to ensure all of it from the roof. The problem with this strength of the solution is it is prematurely hardening the shingles and also will cause the nails to flash rust and that strong of sodium hypochlorite.

Bleach Dilution Chart

Roof Cleaning Guide

Roof Cleaning Technique


Preparation when applying bleach to a roof is paramount. Protection of the plants, siding, and downspouts is a must. This will ensure that roof cleaning the solution does not damage these items. Pre-treat all the landscaping in that area with dowsing it in the water. Pre-wet the plants and soil first and then rinsed again after the job is complete. For added protection also cover your landscaping with light weighing plastic tarps. Then rinse the siding before and after applying the solution. If you do not rinse the siding, the solution can change the color of the paint on the siding. Last, wrap plastic bags on the downspouts to collect whatever solution comes down them. Covering the spouts with bags will catch all the solution that will come down the gutter system This will stop the solution from getting on the landscaping from the downspout.             

Applying the Cleaner

Now you can either use a ladder to stand at the roof’s edge or get on the roof to apply the solution. The solution applied is bleach-based with soap the bleach strength can range between 3% and 4.5% Sodium Hypochlorite. After applying a solution, wait 20 minutes to see if there are any areas that need more solution. Then apply a post rinse of water to the plants. Last, we will remove the plastic bags from the downspouts, and put the solution on a concrete pad. The solution will not harm your concrete, all it will do is clean it.                

If you hire a professional ensure the roof cleaning company only uses low pressure or soft wash techniques. These soft washing sprayers range between 60 and 100 psi. Ordinarily, the strength of the solution can vary between 3% and 6% bleach with soap to allow a better dwelling time. Never allow a roof cleaning company pressure wash your roof. If they use pressure, it will deteriorate your roof.

Pressure Wash or Soft Wash for Roof Cleaning?

At Foxland Cleaning, we never pressure wash a roof. We only use a soft wash technique which has a maximum of 100 pounds of pressure per square inch. Due to the way shingles are made if you use a professional that will pressure wash or even rinse on low pressure, they will deteriorate your shingles causing many of the granules to come off. Companies should only allow soft wash techniques on a roof. One last note, black streaks should come out that same day. However, with growth such as moss, this is just a treatment that will kill it. We will not wash it off sing as the rain we’ll take care of that in a gentler manner.

pressure washing vs. soft washing

If You Hire a Professional Ensure to Get a Cleaning Guarantee

We can treat the moss on your roof so it will come off during heavy rain. The moss will turn to a white cottage cheese look when it is dead. Which means the rain will remove it the rest of the way. The black stains on the roof will come out before we leave the project. However, it is sometimes difficult to see the complete removal of all the stains on the roof. If the growth is not completely removed from your roof, we will treat the roof again at no extra charge. When looking for roof cleaners in your area, call Foxland Cleaning for a professional roof cleaning. We will care for your property as if it was our own.

Hear From Our Clients

"I very highly recommend John Wilson and Foxland Cleaning to keep your home beautiful! Each year, John cleans my gutters and power washes my home. Foxland Cleaning has also removed ALL stains from my roof's shingles. John is a man of integrity who is devoted to service and excellence--qualities which are hard to find these days. And, I have found his prices to be the lowest."

Bill Cox

"We had the house washed and it looks great! John did an outstanding job and we will be having him back to do the driveway soon! Thanks for being so great to work with! The pricing is so good I will never do this myself EVER again!"

keith mackinnon

"Absolutely fantastic job cleaning the driveway! I highly recommend Foxland Cleaning."

Philippe .

"Foxland Cleaning was amazing! We did an online quote, John reached out to me personally and they were out at our house all within the same week. Gutter cleaning was fast and simple. Will definitely book them again in the future. Thank you!"

Caitlin Glover

"Had my gutters cleaned by Foxland and they did a great job. Would definitely recommend. They were able to get out to my house very quickly."

Mike Fields

"I only have praises for the window cleaning from Foxland Cleaning. John is so nice to work with and he does a great job. My husband also gets five stars for having our windows cleaned."

Gray Smith

"John was wonderful. He kept me in the loop when weather caused them to run late and sent pictures as promised. Will absolutely be using them in the future as well as recommending them to others!"

Kristen Tracy
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Foxland Pressure Washing
  • 770-369-5263
  • 6435 Namon Wallace Drive Cumming, GA 30028

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