Bleach for Killing Moss on a Roof

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WHY STORE BOUGHT BLEACH ISN’T STRONG ENOUGH TO KILL MOSS

There is a common misconception that bleach can kill moss. Homeowners go into their local supermarket and pick up a jug, pour it on their roofs and wonder why the moss hasn’t died. This information is faulty because, originally, store bought bleach only contained 6% of its weight as Sodium Hypochlorite [A.K.A Bleach].

6% bleachMIXTURES AREN’T ALWAYS SO CLEAR

There are many faulty ehow recipes on how to mix the bleach. By the time you’re done with even a conservative, 1 part bleach to 3 parts water your mixture isn’t strong enough to kill the moss you were after. Mixing household bleach which originally held 94% of its volume as water with even more water makes for a product that is not potent.

Bleach is about $6 a gallon at this time of writing. It takes about 40 gallons of liquid to properly cover an average homes roof.The roof cleaning costs quickly add up.

Let’s take a look at how easy this can be to screw up, and how difficult it can be for an average consumer to properly and correctly clean his roof:

Original Amount of 6% Bleach

Amount of Water

Strength after Dilution

Gallons of mix required for average 1200 Square foot home

Gallons Total:

1 gallon

33%

4%

40

Bleach: 30 g

   H2O: 10g

You now need a surfactant (something to stop the mix from rapidly flowing into your gutters), Dawn* soap or any surfactant able to mix without causing a reaction to bleach, work well. This is a surfactant that works well with bleach and doesn’t take away from its shelf life.

The mix above is a standard mix roof cleaners use to kill moss. Many times depending on the bleaches shelf life, the mixtures need to be adjusted. Bleach is a very volatile solution that loses its strength quickly and doesn’t handle well with a whole host of surfactants. Mixing the wrong surfactant can be wasteful and leave you with a mixture that doesn’t do what it was supposed to which is to:

  • Kill Moss.
  • Remove Stains.
  • Not Damage the roof it is applied to.

We’ve covered everything except how to get 40 gallons of liquid onto your roof ……. [Continued shortly in: pumps for roof cleaning]

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Black Streaks on Roof

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Chemical Cleaning to Remove Black Streaking from Roofing

Gloeocapsa Magma is the scientific name for those black streaks on your roofing. Gloeocapsa is a form of algae that lives in wet humid climates. These streaks of black are not as evident in the Seattle-Tacoma region due to the majority of roofing material being of dark coloring. If your roofing substrate is light colored, it’s very probable that these stains will be found on your home.

Although, Gloeocapsa Magma is not harmful to roofing, the appearance of a home suffers tremendously. When selling a home the algae stains should be an issue that is dealt with before the home is placed up on the market. These stains are a red flag to potential home owners who may not know exactly what that black stuff is and whether or not it’s harmful to the roofing.

Soft wash roof cleaning with chemicals is a superior method of removing Gloeocapsa. This method of roof cleaning gets rid of these unsightly black streaks while keeping the integrity of the roofing intact. Power washing is not as effective at eliminating Gloeocapsa. It is also very damaging to roofing shingles. Read more here………….

In the picture to the left, a chemical solution is sprayed on the roof. Each chemical in the mix does a certain job. Within 25 minutes, the picture to the right shows the roof stains are almost completely gone. The mix continues to work on the stains and streaks until the next day of rain. After the roofs first shower, the roof is looking its best.

Going from being a white roof covered in black to being a white roof again has strong selling value for a home. Soft Washing is a great way to safely and effectively remove black streaks from your roof in Seattle. Whether your home is up on the market or you just don’t like coming home to a dirty roof, consider chemical cleaning when hiring a roof cleaning contractor.


 

Soft Wash Roof Cleaning Seattle

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Chemical Roof Cleaning

Soft-washing involves the use of chemicals to clean roofs. This method is employed to lessen the amount of damage caused by power-washing. Power-washing on average removes 3-4 layers of granules per cleaning . A roof is known by its years of life:

  •  A 20 year roof has 20 layers of granules.
  •  A 50 year roof has 50 layers of granules.

The soft-wash method when used properly is far more beneficial to roofing substrate then power-washing. No granule loss happens when chemicals are sprayed on your  roofing. Additional benefits include:

  • The elimination of all moss spores that cause moss to grow in the first place.
  • A much longer lasting finished product; on average the process lasts 2-3 years

ARMA [Asphalt Roof Manufacturers Association] recommends soft-wash cleaning for proper roof maintenance. ARMA is the association that governs the making of asphalt shingle roofing. They are the leaders in the industry in the production and proper cleaning methods of roofing materials.

The difference in the finished look of the product : power-washing versus chemical cleaning is nearly indistinguishable, when the proper chemicals are used. A soft wash roof cleaning company generally use a few standard chemical products:

  • TSP [trisodium phosphate]. Known for its ability to remove algae and rust stains
  • Sodium Hydrochloride 10% or higher: known for its ability to kill moss and clean shingle.
  • Borax Lo: A soap like product known to aggressively kill weeds, spores and moss residual.
  • Isopropyl Alcohol: used when aggressive moss has been growing for long periods of time.
  • Surfactant:  used to slow the mixtures path down to the gutter line.

When mixed properly these chemicals generate a long lasting safe products to roofing material. These chemicals are not readily available to the average consumer and the mixtures of this chemical call for exact amounts for a strong enough product. The procedure of soft wash roof cleaning in Seattle is best left to a professional roof cleaning company.

 

Methods of Roof Moss Removal in Seattle

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Over 10,000 roofs are replaced per year due to water intrusion, in the Seattle area. Roof Moss is a major contributing factor to the number of roof replacements. Moss grows in patches 1-3 inches wide. Homes with infrequent sunlight or under foliage are the most prone to moss growth. Large patches of moss trapping moisture in 1-3 inch mats create water dams that then begin pushing water underneath roofing substrate. The roofing material is never left to dry out.The consequences are:

  • Rot.
  • Mildew
  • Buckling

What is Roof Mold?

Bryophytes are soft plants that grow in mats and clumps. They reproduce through periodic release of airborne spores. They have no vascular system to feed themselves as plants with roots do. Bryophytes therefore grow where moisture is prevalent. The Seattle region with between 72-88 days of sunshine a year is an inviting environment for moss growth. Our lack of sun is the reason moss grows so heavily in the area. With no ability to control our amount of sunshine, we are left to do periodic maintenance.

Differing Methods of Moss Control

You can speak to any 2 roof cleaners in the country and the proper method for roof cleaning and moss control is always up for debate. There are standard methods of moss control practiced around the country these methods are:

  • Power washing to remove moss.
  • The use of zinc strips.
  • Chemical treatment.

Power Washing 

Pressure washing without adequate chemical treatment afterwards is the least effective method in killing moss. Without the use of a moss inhibiting chemical you’re left with a roof that will need another cleaning almost immediately. There have been several studies done on the damage a power washer can do to asphalt granules.  ARMA [Asphalt Roofing Manufactures Association] recommends not using a pressure washer on asphalt shingles for roof moss removal. Their primary concern is the loss of granules. Although not as good on asphalt shingles, a power-washing is probably the only effective way of properly cleaning cedar and metal roofs.

The metal roofing vent prevents moss growth.

Zinc Strips

Zinc Strips are effective means of containing moss growth. Due to the cost and the amount of coverage required to kill moss, many times it is unfeasible to use this method. For Zinc strips to successfully control moss growth they must be placed every 3 feet from the tip of the roof to the gutter line. This method is very unsightly and many homeowners do not like the look of Zinc strips going down their entire roof line. The picture above shows CLEARLY, that zinc and metal DO stop moss from growing. Where the metal vents are present; no moss is growing directly beneath them.

To effectively use zinc strips:

  1. Two inches of zinc should protrude the asphalt shingle.
  2. They should start at the ridge cap and end 3 feet above the gutter.

Chemical Treatment of Moss

Chemical treatment, also called soft wash roof cleaning, in our opinion, is the most effective means of moss control. Using the right chemicals, completely kills all moss spores and prevents new moss from rebuilding. Most soft wash roof cleaner’s offer warranties of 1-5 years, they are secure in offering these warranties because they know that it took years for this moss to grow on your roof and it will take years for it to grow back, provided the right chemicals are used in strong enough doses.

The decision on what method is the right method for roof cleaning in Seattle is always up for debate. PWNG uses the chemical soft washing method to soundly control moss. We stand by our service and offer a 1-year warranty with every roof cleaning in Seattle. We look forward to any comments or questions our readers might have and we welcome an open discussion on roof cleaning.

Pressure Washing removes Asphalt Shingle Granules

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Granules, the sand like element that is keeping the rain from destroying your home by way of the roof shingle. Granules are also the reason you should never pressure wash your roof. These delicate granules are held to your roof shingle, layer upon layer by a form of glue. A simple walk on your roof removes some granules, just imagine the damage a pressure washer does to it.

A.R.M.A [American Roofing Manufacturers Association] represents a majority of roofing manufacturers in North America. Their primary concern has been to find common ground on asphalt shingle manufacturing  and the process of maintenance.

Their bulletin on the proper method of roof cleaning 1 is commonly, cited by roof cleaning companies. The three main points of the bulletin were:

  1. Never power-wash asphalt shingles.
  2. Only chemical cleaning can temporary remove and combat algae stains
  3. The only long-lasting way to combat algae is to have AR [algae resistant shingles] installed.

Unfortunately, although Algae resistant shingles are reaching their teen years in service, not very homes being built to this day have them installed due to the higher cost of the shingle compared to a regular asphalt shingle. RCI-online, stated that up to 50% of all roof replacements are done for cosmetic reasons instead of from leakage or wear. 2

Sources cited:

1.http://www.asphaltroofing.org/pdf/tb_217.pdf

2.http://www.rci-online.org/interface/2007-01-ammerman.pdf