Note: This is cleaning/treatment/restoration only. We do not offer roof repair services.

Cedar Roof Cleaning: A Guide to the Cleaning Process and Proper Maintenance

Cedar Shake Roof Cleaning Prairie Village, Kansas 850x433

Three Step Process For A Cleaning Cedar Roof

From the past to present day many cleaners use what is called the 3 step process for cleaning a cedar roof.

  1. Cleaning
  2. Brightening
  3. Staining, Sealing & Weatherproof.
  • The cleaning solution which is commonly used is Sodium Percarbonate.
  • The brightening solution which is commonly used is Oxalic Acid.
  • The staining, sealing & weatherproof can be any number of combinations.

Sodium Percabonate

It doesn’t clean well and requires the use of pressure to completely clean the roof. Thus the use of a pressure washer that is too high (500 to 1000 psi) of pressure and will damage and erode your cedar shakes. Common sense indicates you would not want the pressure of any form used on your wood roof. The downfall to the use of sodium percarbonate is that it takes pressure to remove the solution.

Oxalic Acid

Oxalic Acid, as a brightener solution is a poisonous, crystalline acid used for many industrial purposes including rust removal and bleaching. It is both toxic and caustic. It also requires the use of high pressure to properly remove.

Staining, Sealing & Waterproofing Cedar Shakes

You can stain a cedar or wood roof to take on different hues or tones. Other than cosmetic staining has no true benefit. Sealing is the last thing you should do to a cedar or wood roof as they need to breathe or expand and contract with the weather conditions, thus the spacing between the shakes. Waterproofing has limited effectiveness and has a short shelf life.

Cedar Roof Maintenance

Simply speaking cedar shakes or wood roofs should stay in their natural form as when they were installed. Cedar does not decay in and of itself. Only moisture and different infestations will decay cedar. Cedar does weather and needs to be maintained to last their designed life span. The only maintenance a cedar roof needs is a good cleaning every 5 to 10 years which is subjective on tree cover, moisture, and weather condition.

Cedar is a natural insulator against the environment; competitors can’t come close to the thermal efficiency of wood. In fact, cedar has twice the thermal resistivity (R-value) of asphalt, 5 times that of slate, 8 times that of concrete, and hundreds of times that of metal and aluminum.

Cedar roofs don’t decay, but they do weather. It has natural preservatives that resist moisture, decay, and insect damage. Although in warm, humid climates and on heavily shaded roofs, algae, moss, mold, mildew, lichen, and fungi will grow, because these organisms retain moisture the cedar will decay in time if not maintained.

When new the shakes and shingles display the natural honey and cinnamon tones, and will later mature to a seasoned and distinguished-looking silvery gray when properly maintained.

When Your Cedar Shakes Need To Be Cleaned

If the shakes or shingles display brown/dark brown to black tones, these are signs of harmful organism infestations and they need to be cleaned. The same applies to moss, mildew, lichen, and fungus.

With a proper cedar roof maintenance program a cedar roof will last anywhere from 40 to 60 years which is also subjective to conditions and if maintained.

There is an alternative to the 3 step process for cleaning cedar shakes or wood roofs and for roof cleaning.

It is a 1 step process: Cleaning. In today’s roof cleaning industry the process or equipment used to clean a roof is what is called the non-pressure or Soft Wash process. The solution is applied with a 12-volt pump system with an average pressure of 60 psi and the rinsing process is done with a simple garden hose pressure or about 40 psi. Watch the videos to your right on how the process works and the equipment used.

As to the cleaning solution, there is also an alternative that is non-toxic and caustic. The cleaning solution is a Citric based cleaning solution ( not citric acid) that contains algaecide, mildewcide, and fungicide. Though cedar shakes only have a 3% oil content when installed, there is a water base oil in the solution that helps rehydrated the shakes. This solution is not for sale as it was developed personally.

Cedar Roof Cleaning Costs

On average the cost of a cedar shakes roof cleaning should be about $0.50 a sq. ft. or less than 10% of replacement cost.

So when considering having your cedar roof cleaned do your research. There is a difference between someone who can clean a cedar roof and someone who is a cedar roof cleaner.

This is my sole opinion based on my research and years of experience with cleaning cedar shakes roofs.

Bruce Sullivan, Owner
Sullivan Roof Cleaning, Inc
Service all of Iowa and the Greater Midwest

Cedar Shake Roof Cleaning in Des Moines Iowa
Cedar Shake Roof before & after cleaning

Meet Bruce

50 Years of Experience &
Over 2,000 Shake Roofs Cleaned

Bruce Sullivan has over 50 years of experience in maintaining, cleaning, and restoring cedar shake roofs. Making him one of the top authorities on cedar shake roofs in the US.

Watch the Cedar Shakes Cleaning Process in Action in this video

Play Video about Roof Cleaning How to Remove Moss, Lichen, Fungi from a Cedar Roof Sullivan Roof


What can I say? Bruce and Keith provided an exceptional service, and they are really nice guys too. Found out at the last minute they were in Minneapolis, and they fit me in for a cedar shake roof cleaning the next evening after their regular job was done. Even cleaned up my gutters, small fence, and small deck at no charge. The place looks outstanding! Highly recommended.

Mike Richards

I highly recommend this business. Due to the work performed we are going to get another 10-14 years out of our cedar shake roof. We were told by some roofing companies that the roof should be replaced in 2 years. I lucked out and found Sullivan Roof Cleaning while researching companies that perform this service, and was pleased to learn that the company does work outside of Iowa. If you need your cedar shakes cleaned, go with Sullivan Roof Cleaning.

Eric Oelrich, 
St Cloud, MN

Bruce did a great job cleaning the whole exterior of my house. The roof has new life! It looks practically brand new. All the mold and moss on the roof, on the gutters, under the eaves, completely gone. He exceeded all our expectations. When he tells you what he can do for your house, you can believe and trust him. Great guy, great service.

Stuart Malone
Kansas City, MO


Cedar shakes are organic. Though a resilient material. Being organic they need to be maintained. Over time, like any organic material that are subjected to weather elements, they reach a stage of deterioration. Like UV exposure, moisture and seasonal changes. Which results in moss, mold, mildew, lichen and brown rot fungi. These infestations need to be removed to further preserve the integrity of the cedar shake.
The proper way to clean a cedar shake roof is from a ladder. By spraying a special formulated solution onto the shakes and then rinsed with a garden hose pressure. Best done by a professional cedar shake roof cleaner. Not DIY recommended.
No. Pressure washer will require walking on the shakes, which will harm them, and even at its lowest setting will also damage the shakes.
On average, cedar shakes should be cleaned every 10 ten years. Subjective to the grade of the shakes and the amount of surrounding tree cover.
Avoiding walking on a cedar shake roof, other than for repairs.
Never seal a cedar shake roof. Cedar shakes need to breathe. They expand and contract in rain conditions. Seal will shorten the lifespan, to the point of premature replacement.
Staining has no real preserve value and can also harm the integrity of shakes, as stated, they need to be able to breathe. Also, if the shakes are not properly cleaned staining can seal the deteriorating infestation within the shakes.
Depending on the grade of the shakes and installation, and if maintained properly, 40 to 60 years.

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