Note: This is cleaning/treatment/restoration only. We do not offer roof repair services.
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When How and Why to Clean a Cedar Roof

Cedar Shakes


In today’s roof cleaning industry we find more and more cleaning services adding roof cleaning to their services provided. In the last couple years many want to take on the service of cedar roof cleaning. Unlike other roof materials e.g. ashault, tile, slate and metal, cedar is a roofing material all to itself. Just in its nature of being organic and a soft wood much caution is warranted when considering having it maintained or cleaned.

Cedar Roof Cleaning

It Starts with the Solution

First off, you cannot use the same cleaning solution used to clean asphalt, tile, slate, or metal. The solution has to be specially formulated to not harm the cedar but at the same time clean it properly. Cedar has other infestations like white and brown rot fungi growth that you won’t see in other roofing materials. These fungi which are the real white-looking shakes and the brown to black color shakes will deteriorate a cedar roof faster than any other infestation.

Wood Destroying Fungus on Cedar Roofs

Wood destroying fungus (fungi, plural) causes more damage to structures than all the fires, floods, and termites combined! The wood-decaying fungus requires four fundamentals to survive which are oxygen, favorable temperatures, water, and food. The fungus occurs generally when the moisture content of wood exceeds 20 to 30 percent, coupled with optimal temperatures (32 – 90 F), an adequate supply of oxygen, and a suitable source of energy and nutrients.

Fungus is a plant that lacks chlorophyll. Unable to manufacture its own food, it feeds off of cells in the wood. The fungus secretes enzymes that break down the wood into usable food. Fungi will significantly reduce the strength of the wood if the condition continues over a period of time.

How to Clean and Remove Algae, Moss, Mold and Mildew, Lichen from Your Cedar Roof

Walk on a Cedar Shake Roof
A Cedar Shake Roof should never be walked on!

Thus it takes a specially formulated solution to remove such, combined with the removal of algae, moss, mold and mildew, and lichen. So for someone to use let’s say bleach, soap, and some potpourri for a good smell effect will only do more harm to the cedar shakes and will not properly clean them.

To properly clean a cedar shakes roof there has to be something to kill the bacteria, algaecide, mildewcide, and fungicide mixed in a proper ratio for the infestations within the cedar shakes. There is no one product on the market today that will do that. They have to be mixed up special.

What Home Owners Should Know About Their Cedar Roofs

What many cedar shakes homeowners don’t know is that 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.

Also to help the cedar shakes extend their lifespan there has to be a water-based oil within the solution to replenish the natural oils that leach out over time. Cedar shakes have to breathe. Thus it has to be water-based. They contract and expand that is why there are spaces between. Staining other than looks does little for the health of the shakes. Sealing should never be applied, again they have to breathe. Just a regular cleaning will serve just fine and allow the shakes to live out their full lifespan which can be anywhere from 40 to 60 years and maybe even longer.

You cannot properly clean a cedar shakes roof any time of the year. The ambient air temperature has to be consistently 50 degrees or above for the shakes to properly thaw and release the infestations from their dormant state. To do otherwise is a waste of time and money. You could possibly brighten them but you will not clean them.

In order for a cedar shakes the roof to last its full lifespan it has to be maintained or cleaning, in most cases about every 6 to 8 years, depending on climate, tree cover and shade coverage. Cedar is organic and is wood, it has to be maintained. It is not different from your teeth. Why do you have them cleaned? So they will last their lifetime. They are organic also.

Also, for you cedar shake homeowners. Cedar shakes are cost saving to your home. 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.

I hope this will be informative for you cedar shakes homeowners. When hiring a cedar shakes roof cleaner check them out. What process do they use? You should never use high pressure or a power washer to clean a cedar roof, that is just common sense. What experience do they have? Ask for references. Have them provide examples of their work. Do they have customer reviews that can be verified? Are they insured?

Ask For a Cedar Shakes Roof Cleaner

There is a big difference between a person that can clean a cedar shakes roof and a person who is a cedar shakes roof cleaner. That difference could be thousands of dollars in damage or replacement cost. On the other hand if they are a cedar shakes roof cleaner you can save thousands of dollars in premature roof replacement by simply maintaining your roof.

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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