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The cedar roof on my home is about 15 years old. Over the last several years I’ve had maintenance completed to replace bad or missing shingles but I’ve been secretly waiting for a hailstorm so that I could just replace it. Since that won’t probably ever happen I was searching for ways to extend the life of a cedar shake roof and I ran across Bruce Sullivan’s website. I watched the videos, looked at the pictures, and then traded some emails with him asking questions. I am so happy I found him!

Bruce and his crew were very professional, they left no mess, and my roof looks nearly brand new again. I had a covered patio added last year that was built into my roof line so those shakes were still fairly new and stood out from the gray dingy look the rest of my roof had. Not anymore! Now the entire roof blends together.

I highly recommend Bruce Sullivan and Sullivan Cedar Roof Cleaning to anyone. I feel the price was a good value for the work they performed, but more importantly the results.  

I’m no longer hoping for a hail storm, my insurance deductible is more than the cost to clean my roof again and add years of life to it. I’ll see Bruce and his team 7 – 10 years from now when my roof needs it again.

Bruce Brown, Kansas City, Missouri



Cedar Roof Cleaning, Omaha Nebraska

Our experience with Bruce was amazing. Our roof looks like new again. Bruce’s knowledge of shake roofs is unmatched by anyone in the roofing industry. The day our roof was cleaned, I came from from work and other than a clean roof, I would have never known they were there. Great job, recommend to everyone with a shake roof.

Dawn Nevarez, Omaha, Ne.

Bruce and Maria are a great team and provided professional service. I was concerned about the dirt coming off of my roof effecting my patio and shrubs. Maria did a marvelous job of cleaning up from the waste coming off my roof. When I need my roof cleaned again I will certainly call them.

Bob Thomas, Omaha, Ne.

Are you in the process of selling your home with a Cedar roof?

Clean vs Replace your Cedar Roof when selling your home

I have had a number of cedar roof cleanings where the home owner that was selling their home was told they needed a new roof. When you put your home for sale in most cases there is a home inspection. Many home inspectors are not roof inspectors per se. When it comes to cedar wood roofs many times the inspector will base their inspection more on the age of the roof than on the condition. Rule of thumb is if a cedar roof is twenty years old it is near replacing which is based solely on the age. Given many home owners do not understand the design and function of a cedar roof they just assume they must need to replace the roof if the inspector says so. What many home owners and even home inspectors don’t realize is twenty years for a cedar roof, in most cases, is just half-life.

Do you need your Cedar roof replaced or cleaned?

I have cleaned hundreds of cedar roofs and also I am a certified roof inspector with the National Certification and Roof Inspection association. Our policy is we will not clean a cedar roof that is in need of major repair or replacement.

I just cleaned a roof where the home inspector told the home owner and buyer that the cedar roof had maybe one to three years life left. I was called and asked to review the possibility of cleaning this roof. At first glance the roof looked bad having that dark brown to black color and that worn out look. I inspected this roof and the underling or what we call roof felt was in good condition and the shakes didn’t have a lot of vertical cracking or missing shakes nor cupping and curling. The cedar roof had never been cleaned and had mildew and brown rot fungi and was holding moisture. Over time these infestations will leach the life out of the shakes. cedar cannot decay on its own. Only when infested with algae, moss, mold, mildew, lichen and fungus, white and brown rot will they hold moisture and thus deteriorate the shakes. What one needs to understand is with a cedar roof the underling or felt protects the roof or home and is the water barrier and the shakes protect the felt. In most cases a simple cleaning will resolve the issue and place the roof back in its normal functioning condition.

How much can be saved cleaning vs replacing your Cedar roof?

The buyer wanted the home owner to replace the roof or lower their sale price based upon this home inspection at a cost of $25,000.00. I have since cleaned this roof at the request of the new buyer for less than 5% of the replacement cost. In six to eight years we’ll clean it again. Here is what it looks like today:

Clean vs Replace your Cedar Roof when selling your home

In most cases a cedar roof that is in the twenty year old range doesn’t need to be replaced but a simple cleaning will return it to its normal functioning state.

This example is classic of a situation where the cedar roof could have been replaced prematurely. Whether selling your cedar roof home or not, do your reasearch have it inspected by a cedar roof expert and consider having it cleaned. Cedar is wood and organic and needs to be maintained. Like your teeth which are organic also and will last a life time if you do what, maintain them. If maintained cedar roofs can last anywhere from 40 to 60 years which is subjective on weather conditions, location and tree cover around the roof. We clean cedar roofs throughout Iowa, Nebraska, Minnesota, Wisconsin, Missouri, Kansas and the greater Midwest. Review the rest of this website the videos, photos and customer reviews. Don’t replace your roof when we can clean it!

I get e-mails and phone calls weekly about how someone can clean their cedar roof throughout the U.S. and Canada. Most requests are to buy my solution. I do not sell it.

Cedar Roof Overview

The following is an overview for all you cedar roof homeowners. If you have done your research or are about to, you will find the following will hold true as a common theme for cedar roof care.

Professional Roof Cleaning by Sullivan Roof Cleaning

Wood shingles and shakes can provide superior performance in areas that experience high winds or damage from hail. Although they do have certain limitations (susceptibility to rotting, splitting, and warping), proper maintenance and care can minimize these limitations. See also:http://www.cedarbureau.org/cms-assets/documents/45094-350971.cmbrochure2011.pdf

Most wood shingle and shake roofs are made from western red cedar (Thuja plicata) because of its exceptional properties, including defect-free straight grain, dimensional stability, low weight (low density), impenetrability to fluids, and probably most important decay resistance, derived from natural substances found within the wood. In this discussion, when I mention shingles and shakes, western red cedar is the species I mean.

Other wood species, notably redwood (Sequoia sempervirens) and cypress (Taxodium distichum), have similar properties and are sometimes used; but decreasing supplies significantly restrict production and distribution.

Cedar Roof Weathering

When wood is exposed to the effects of sunlight and precipitation, its surface begins to change. This change is partly physical and partly chemical, and it’s cumulatively referred to as weathering.

The first noticeable change is the color. The initial red-brown color tends to fade, and a graying process begins. This change to a silvery gray is the result of ultraviolet radiation from the sun stripping the surface layer (less than 0.01 inch deep) of certain cell-wall materials.

This first change in color is rather rapid, occurring within the first year of exposure (under more severe conditions, within several months). Gradually, the silver gray will change to a darker, more graphite gray, then to a brown/black color indicating the colonization of the surface by micro fungi that complete the initial phase of the weathering process. White and Brown Rot Fungi�s.

By nature, wood rapidly attracts water to its surface. When this happens, the wood swells. As it dries and the moisture content decreases, it shrinks. This repeated wet to dry cycling causes the development of compression and tension stresses; these, in turn, cause microscopic cracks to develop.

Over time, these cracks grow larger and larger, caused by additional wettings or by freezing and thawing. The cracks also trap water and allow wood-rotting organisms to penetrate deeper into the wood. As the water penetrates deeper, the wood becomes harder to dry. With increased moisture, the wood-rotting organisms prolong their destructive activity and damage more wood material than would occur during normal weathering.

As the roof continues to age, the surface and sharp edges from manufacturing are eroded by abrasive particles carried by wind and water and by the action of sunlight. Wood-destroying organisms also continue to slowly degrade the surface and the thicker butt edge. The roof loses its new appearance. Debris from trees accumulates in the valleys and between the shingles.

After each rain, some areas stay wetter longer. Soon, other plants are beginning to grow, primarily lichens and mosses. More debris collects, and the roof appears to be natural and rustic. There are splits developing, and in certain areas cupping and curling begin to become more apparent. Then the leaks begin. Sometimes, this takes 30 years sometimes, much less.

Cedar Roof Care and Maintenance

Good housekeeping for a wood roof requires removing all leaf litter, pine needles, and debris that accumulate between the shingles and shakes and in the valleys of the actual roof structure. It’s best to do this before the wet season begins.

The debris that accumulates has two deteriorating effects on the roof. First and foremost, debris tends to retard the shedding of water. Secondly and more destructively debris retains moisture that allows wood-destroying fungi to grow.

Wood-rotting fungi require water as part of the life cycle. If you can reduce the amount of water so that the minimum level is never reached, the organisms can’t grow.

To promote drying, it’s very important to remove overhanging branches that excessively shade sections and retard the drying of the roof surface. Never allow tree branches to touch and rub against the surface of the roof. The mechanical action of this rubbing can literally wear sweeping grooves into the surface of the shingles or can loosen the fasteners that hold them.

Finally, in very woody areas, branches may retard air flow so that surfaces dry very slowly. In all cases, you’ll need to make sound judgments about pruning, trimming, or removing problem-causing trees. Excessive growth of lichens and mosses is a sure indicator that your roof is not drying properly and that enough moisture is available to support wood-rotting organisms.

Removing the debris accumulation is relatively simple. In most cases, anyone who’s willing to climb on the roof can wash off most of the material with a garden hose.

It’s easy to remove litter from around chimneys and in valleys; you also need to clean all the keyways (those areas between the individual shingles and shakes).

Professional services sometimes use high-pressure washers (available through rental firms). These are not recommended because cedar is a soft, low-density wood. Excessive or imprudent use of high-pressure systems can detach shingles or erode many years of wear in moments even though the roof will look like new.

Chemical Treatments For Cedar Roofs

There are several types.

  1.  You can easily prepare cleaning solutions to help remove dirt, mild stains, and light growths of molds and mildew.
  2.  For more persistent stains, bleaching formulations will be recommended.
  3.  In some cases of excessive moss growth, you can apply chemical solutions to kill the mosses and any fungi that may be present.
  4.  You may sometimes apply preservative chemical solutions that will retard the growth of molds, fungi, and mosses.
  5.  Additives such as pigments and ultraviolet absorbers can slow deterioration caused by sunlight.

Considered as a whole, the chemicals listed below are chosen for their fungicidal or herbicidal effects. Note that these chemicals will perform differently under various environmental conditions. As a result, the frequency of application required for long-term protection depends on the chemical you use, the amount of precipitation, average temperatures, and the roof exposure conditions.

The chemicals recommended are available in products found in hardware stores, building supply centers, or lumber yards.

Cleaning Solutions For Cedar Shake Roofs

Because I have developed my own cleaning solution, which not only includes the proper cleaning ingredients i.e. algaecide, mildewcide and fungicide, etc., but also has preservative ingredients within the solution and for business purposes I will not detail in this overview.

For the purpose of this overview I will discuss what is the common recommended cleaning solution based upon research. You’ve removed the debris from your roof, and you can see light staining or irregular discoloration. Cleaning the roof with a mild detergent solution may provide an improvement.

Bleaching Formulations

For more persistent stains, you can increase the sodium hypochlorite (chlorine bleach) concentration, even to the point of using it full strength from the bottle for spot applications.

Formulate stronger solutions by using granular chlorine (calcium hypochlorite), mixed at a rate of 2 oz. per gal water. This chemical is used for algae control in swimming pools and is available through pool supply houses.

For safety, wear eye protection, rubber gloves, and aprons. It’s best to apply these bleaches with brushes for small spots; spray large areas (use plastic or stainless steel sprayers).

Don’t let bleaching solutions stay on wood more than hour before rinsing. These solutions provide more uniform results when you use them in lower concentrations; repeat the application, rather than use a single high concentration when you start.

It’s best to use these solutions out of direct sunlight. Apply the chemical only to the stain. Avoid drips, runs, and splashes of bleach or excessive bleaching on the roof surface these can mar the roof’s appearance. It’s not necessary to scrub bleached areas, but rinse the wood thoroughly.

Preservative Treatments For Cedar Roofs

Chemical solutions may also be applied to red cedar shingles and shakes that will retard the growth of molds, mosses, and (more importantly) wood-rotting fungi. These chemicals are most commonly referred to as wood preservatives, and they’re an effective means of extending the life of your roof.

When you apply preservative chemicals to your roof, the roof condition at the time of treatment will determine the actual amount of increased longevity. If a roof has aged for many years, the treatment won’t be as effective simply because the years of exposure will have taken their toll. In all instances, except when the roof is badly deteriorated, you can expect preservative chemicals to extend the life of your roof.

When you apply preservative chemicals to shakes and shingles, you need to remember several important considerations.

First, the coating should be as uniform as possible. Avoid drips and runs. It’s better to apply several light coats and obtain good absorption than to try and force it in all at once. The important point is that you’re trying to reach a certain level of preservative retention. If the retention level is too low, your treatment will be ineffective.

Second, since much of the decay occurs in the butt region of the shingle or shake, it’s a good idea to be conscientious when you apply the solutions, to cover the exposed butts as well as the exposed shingle surface.

The three methods available to provide proper application are brushing, using a thick-napped roller, or spraying. Because of the irregular surface, you’ll probably get a more uniform coating with a multigallon, pump-type sprayer set to produce a coarse spray.

Spraying also requires a calm day (wind less than 4 mph) to prevent overspray from drifting over plants or into your neighbor’s yard. Brushes are also effective because they allow for thorough treatment of the keyways and ends.

The chemicals listed below will most likely be part of formulations in over-the-counter products or part of the formulations applied by roof servicing contractors. These chemicals are also available in concentrated form through specially licensed supply companies. This is because of the toxicity, possible problems in preparation, and the limited demand from home owners. In every case, regardless of the concentration, be extremely careful when you apply, handle, expose, and store it. When you purchase over-the-counter products for long-term moss control, be sure that one of the wood-preserving chemicals listed below is on the label.

Currently, the preservatives in the following sections are available as either aqueous solutions or oiled-based products.

Copper Naphthenate this is an effective preservative well-suited for applying to roofs. Solutions should consist of at least 1 percent copper (2 percent is better); apply them at a rate of 1 gal/100 sq. ft. for shakes, and 1 gal/150 sq. ft. for shingles. Literature indicates that using this concentration will provide up to 5 years of protection in the Pacific Northwest. Note that copper naphthenate has a greenish color that may prove unsightly. To overcome this, choose a solution that’s pigmented to simulate the red-brown cedar tones or use another type of preservative.

Zinc Naphthenate While copper is much more effective than zinc in retarding the growth of biological organisms, people use zinc solutions to retain the more silver or gray appearance on the roof’s surface. It’s recommended that you use either more frequent applications or higher concentrations of active metal content for example, 2- to 3-percent solutions for 3 years of protection (or 4 percent for 5 years) per 100 to 150 sq. ft. as above.

MTC and TCMTB MTC are (methyl bis [thiocyanate]). TCMTB is (2-[thio cyanomethyl thio] benzo-thiazole). These generally are used in combination as an effective roof treatment. They can be used in clear coatings or in pigmented solutions, and either as waterborne solutions or with solvent/oil mixtures.

Copper 8 Quinolinolate this is a safer alternative to those listed above, but some tests indicate its effectiveness is short lived not much more than 12 to 18 months.

Polyphase Ployphase is 3-iodo 2-propynyl butyl carbonate. In solutions where concentration levels are greater than 0.58 to 2 percent active, you might get 2 years of protection. The durability and long-term performance of this product is still unknown, but it’s limited because of light and water sensitivity.

TBTO TBTO is tri-butyl tin oxide. Some literature indicates its use is questionable in treating existing roofs because of mold and mildew resistance and chemical degradation. It’s often used together with trichloromethyl thio phthalimide (Folpet), which has weak fungicidal properties.

Zinc and Copper Strips For those who prefer not to use toxic chemicals, there appear to be safe and relatively inexpensive treatments to control moss. Galvanized metals have a surface coating of zinc. For example, if you fasten a 2-inch-wide strip to either side of the ridges and run it the entire length of the roof, rain will leach zinc from the metal’s surface and wash it down the roof.

As noted earlier, zinc can effectively kill or retard the growth of mosses and fungi. Its effect has long been noted in personal correspondence between wood scientists; this effect is prominent below chimney flashings and vents.

However, I couldn’t find any scientific study to verify how long it will remain effective or how much metal is required. Its effect below chimney flashings can be seen for at least 15 feet and appears to last for the life of the flashings.

If your roof is so large that the material at the ridge doesn’t retard moss growth at the bottom, place more strips across the surface. After a year, you should be able to judge how well the strips are controlling the growth of moss; add more if they’re needed.

The greater effectiveness of copper over zinc has been noted with copper and zinc naphthenate. So copper strips are also likely to control moss, and possibly retard wood-decaying organisms, because of the greater effectiveness of the copper. This fact has been observed below copper flashings.

In one case, on a roof considered a favorable site for moss growth, two strands of 10-12 gauge copper wire had been placed, one near the ridge and one some 15 ft. below (at the halfway point on the slope). No moss was observed growing. As with the zinc strips, I couldn’t find any supporting scientific studies to confirm these methods but those willing to try may obtain favorable results.

Cedar Shake Roof Oil Treatments

Oils are sometimes advertised to replenish the natural oils in the wood. In red cedar, these oils account for less than 3% of the total mass. While they do contribute to dimensional stability and decay resistance, applying replenishing oils to weathered shingles may be of questionable value, especially if they contain no preservative or water-repellent chemicals.

You might get some temporary benefit, however, with regard to controlling cupping and warping. But some information indicates that applying oils may have some limiting factors. The main limitation is that unless you include an effective mildewcide or preservative, oil like linseed may provide an additional food source for mold, mildew, and fungi.

Furthermore, petroleum-based products are likely to be oxidized (broken down) by sunlight, to have only a short-lived effect, and to increase the flammability of your roof.

Stain, Varnish or Seal for Cedar Roofs

Whatever you do, do NOT stain, varnish or seal your cedar roof. Cedar needs to breathe.

New Growth Cedar vs. Old Growth Cedar

There has been debate about the newer cedar not being as good as the older cedar?

The way I see it. Cedar is not man made, nor a hybrid, but a natural wood.

Any material in life will be as good as you care for it. Your cedar roof is no different.

Let me ask? Why do you go to the dentist to clean your teeth? Because they are organic they need to be cared for to reach their natural lifespan. A cedar roof is no different; it is organic and needs to be cared for to reach its natural lifespan!

NOTE: The materials or information cited above came from research from many different sources, in part, and from my personal experience. This writing is for informational and educational purposes.

Though any person can DIY, I would recommend that they hire a professional.

Bruce Sullivan is a cedar roof cleaner from Des Moines, Iowa area. He has also offered his service throuhgout the Greater Midwest.

Credit goes to research done by:

S.S. Niemiec, former Research Assistant, College of Forestry, OSU

T.D. Brown, Professor emeritus, Wood Science, OSU

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.

Sullivan Roof Cleaning | Before and after photo | Swisher Iowa

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! Wood decaying fungus requires four fundamentals to survive which are oxygen, favorable temperatures, water and food. 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 lack 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

Thus it takes a special formulated solution to remove such, combined with the removal of algae, moss, mold and mildew, and lichen. So for someone to use lets 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, mildacide 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’s 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 is 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 anytime 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 other wise 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 life time. 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.


Extremely Professional

Sullivan Roof Cleaning was extremely professional throughout the entire process of my cedar shake roof cleaning. The results exceeded my expectations and I am grateful for the extended longevity of my shake roof. I would recommend Bruce and Maria to anyone looking to return their cedar roof to new looking and extend its life.

Thank you,

Todd Schissel-West Des Moines, IA

Like A Brand New House

I can’t believe a difference Sullivan Roof Cleaning made! It’s like we have a brand new house! Bruce and Maria were professional and efficient, and what a value! They are passionate about the service they provide, and were as excited about the beauty of the finished result as we were. We will call them again in the future, and much earlier this time. See you in a few years, Bruce.

Jon Rippentrop, Swisher, Iowa

My Roof Looks Brand New!

My roof looks brand new! Bruce explains in his video how cedar roofs can become damaged over time if not properly maintained. We are the third owner of our log home; it was built in 1992. We were not told by the real estate agent or the previous owners to have the roof periodically cleaned. It was by accident that I found Bruce’s website. He did a great job–I can smell the cedar when I go outside, which means the wood is breathing again. I’ve attached a few pictures so others can see what a huge difference Bruce’s cleaning made!

Denise Church, Oak Grove, Ill.