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How to Tell if Cedar Shake Roof is Bad & Needs Replacement

How to Tell if Cedar Shake Roof is Bad & Needs Replacement


A Cedar Shake Roof is an organic roof that needs proper maintenance to ensure it reaches its typical lifespan, if it is not cleaned roughly once every 5 – 10 years then this will likely be at around year 20 rather than year 45 or 50!

It can be hard to tell if a cedar shake roof is bad and needs replacement so in this article, we will go through a few things to look out for and check.  Sometimes you may think that your Cedar Shake Roof needs replacing, but in fact, the roof only needs to be cleaned to allow it to be restored to its former glory. So, the most important point is being able to tell if Cedar Shake Roof is bad and needs replacement or if it just needs a professional clean.

When trying to check the roof yourself it should be done from the ground without climbing up onto the roof, if you do wish to take a closer look this can be done with a ladder but be careful to make sure the footings are secure and the ladder is stable before climbing up. Please be aware you should never walk on a cedar shake roof as this will cause avoidable damage to the shakes.

The Condition of Your Roof

Sometimes it might be obvious that you need a cedar roof replacement – perhaps the roof is falling in? (Then you would likely not be in the house!)  There are warning signs to look out for and fix before a roof replacement is needed.  Some of the signs are visible interior leakage, moss growth, fungus infestation, damaged shakes or shingles, cracks and breaks, warping, and missing shakes is a sign that you need to fix those problems immediately – but they are not a cause for replacement. It is always worth asking the opinion of a professional cedar shake roof cleaner to get their opinion on whether it can be saved or not. This will be free to do and will likely cost you 5% of the price of a new roof replacement.

The Condition of Your Roof​

The Age of Your Roof

The Age of Your Roof

The expected lifespan of a Cedar Shake Roof is almost 35-50 years, less than this is a sign it just needs a professional clean. As the roof ages, it is prone to more damage. Moreover, the quality of the initial roofing material and installation also has a direct impact on the aging of your roof. If the roof has lasted for 35-45 years with proper maintenance and cleaning it means that now it’s now likely time to replace it. 

Water Leakage on Your Cedar Shake Roof

Leakage is a very common problem with any type of roof installation as it ages, this is generally caused by heavy rains, storms, freeze-thaw conditions, warping, materials deterioration combined with the roof has changed slightly since it was first installed. You can generally spot water leakage only after it is too late, once the water has passed the cedar shakes, penetrated the felt underlay and made its way into the wood, and come out the other side, this is generally a sign that the leak is well developed.  In order to prevent this, regular maintenance will keep the shakes and shingles in good shape and you will know that the roof will need replacing as time passes and its typical lifespan begins to approach.  If a cedar shake roof is not maintained then it will likely last around 25 years before a leak develops and it falls into disrepair and the condition deteriorates rapidly.  If maintained then around 35 – 50 years of life before a replacement is due.

A leak is a serious issue as it will not only cause irreparable damage to the shakes, the underlayment, and the structure of the roof but it can also begin to damage the interior of the house such as the walls, ceiling, plasterboard, and any wood will begin to rot. It is essentially disastrous and the roof should be fixed and repaired, or replaced as quickly as possible.  A clean won’t help you here!

Water Leakage

Cedar Shakes That are Cracking

Shakes Cracking

Cedar shakes are natural, organic, and made from the wood of a cedar tree.  There are various different grades of cedar shakes and these will often dictate how long the shakes will last before any possible cracking develops. Cedar shakes go through a vigorous process of expansion and contraction repeatedly year on year due to the moisture and weather, this can eventually take its toll and cause the shakes to crack.

When considering a roof replacement it is worth taking into consideration the age, will replacing the cracked shakes be worth it in the long term, will the roof suffice with a clean and a cracked shake replacement or will the more efficient action be to replace the roof as it will need to be done in a couple of years anyway?  Cost also plays a role in this decision but it should not be the main leading factor.

Cedar Shakes That are Curling

Similarly to cracking the amount of time this will take depends on the grade of the initial shakes, local weather conditions, and even perhaps if you have been miss-sold cedar shake oil.  Curling can occur after a period of time and can lead to gaps appearing and allowing water to penetrate into the felt underlayment and perhaps into the roof framework. 

Some curling is normal and expected but if it appears excessive it is time to call in a professional cedar shake roof cleaner and ask their opinion on the next best steps forwards.

Curling of Shakes

Cedar Shakes That are Splitting

Shakes Splitting

Another sign that tells that Cedar Shake Roof is bad and needs replacement is the splitting of the shakes. Cedar shakes can get split due to extreme weather effects and the continued expansion and contraction of the shakes over time.

The splitting of cedar shakes can occur with newer shakes, generally of a poor grade, or older shakes that have been subject to years of stress.

Depending on the number of shakes that are split and the age of the roof will dictate how you should look at the situation.  Much like in the other sections you need to look at how many years are likely left for your roof, the cost of changing and repairing the damage section, a professional clean to ensure the life of the roof lasts as long as it can and compare that to the cost of a cedar shake roof renewal.

Rotten Cedar Shakes

Cedar Shakes are natural and exposure to rain, humidity and a combination of organic matter and infestations can cause the shakes to rot. 

Cedar shakes will dry themselves out, but if they are unable to, due to organic growth covering them, continued water on the shakes, shaded areas, or various other reasons, the shakes can begin to rot.  A cedar shake that is well maintained will not rot on its own, it requires external “help” from other materials. 

Rotten Shakes

Moss, Algae, & Fungus on Your Roof

Moss & Algae

Moss, Algae, and fungus are bad news for cedar shake roofs and will speed up any degradation and the deterioration of the roof.  Cedar shakes are naturally resistant and once moss, algae, or fungus arrive on the scene they trap moisture between themselves and the shake.  This leads to a constant wet area on the shake which means it never truly dries itself out and will begin the process of rotting and decomposition.

Ensuring that you have these infestations removed will allow you to keep your roof in better condition for longer and therefore delay the need to have your cedar shake roof renewed.

You can reduce the risk and likelihood of these infestations arriving on your roof by ensuring that local tree growth is kept away and not overhanging the roof, it is also important to make sure the gutters are clear and the roof is draining correctly.

You will likely be able to have your roof cleaned once every 5 – 10 years depending on your surrounding local environment and weather conditions.

Pests, Insects, & Termites in the Wooden Shake Roof

Pests, insects, and termites are common problems with wooden roofs because they attract insects as the shakes are degraded by fungus, algae, moss, and other elements which create small natural habitats. Cedar Shakes are naturally termite repellent but not repellent to other infestations when degraded by external factors. If neglected insects can damage your Cedar Shake Roof badly, having your roof regularly cleaned will help to eliminate this risk and reduce the chance of having to replace your roof prematurely.

Pests, Insects, & Termites in the Shakes

Missing or Damaged Cedar Shakes

Shakes Missing or Damaged

Obviously, if you have cedar shakes missing from your roof then this will need to be resolved ASAP.  The missing shakes will weaken the others and surrounding shakes and allow water to directly penetrate onto the felt underlayment below.  The shakes are needed to take the main body of water and if missing this can speed up the need to renew the underlayment.

Missing shakes are not something that can be cleaned back into good health and should be dealt with as soon as you can.  Once the shakes are repaired getting the rest of the roof cleaned in order to prolong the life of your roof for as long as possible is a great idea.

In Conclusion

A man spraying a roof with a hose.

Cedar shake roofs are wonderful and beautiful things, they can transform your house into something charming and fascinating but they do require a certain level of care and attention.  Without this, the cedar shake roof will likely need replacing before it should and will cost you more than it should.

By fixing any major issues immediately you can keep your roof healthy when combined with a professional clean from a knowledgable cedar roof cleaner your roof will last for years.

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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