What is a cedar shake roof?

A cedar shake roof is a roof made from a type of cedar tree. The two types of cedar that are most commonly used in roofing are the Western Red Cedar and the Alaskan Yellow Cedar.

The Western Red Cedar, as the name suggests, is native to Western North America, most notably Washington state and British Columbia. Its application in roofing can be attributed to many things, including:

  1. It has few knots and tight grains
  2. It’s an attractive wood
  3. It’s long-lasting and durable
  4. It’s lightweight yet strong

Western Red Cedar isn’t just used to make cedar shake roof shingles; it can be found in many products, from canoes to instruments ― wood instruments, we presume. The Alaskan Yellow Cedar hails from the same general area as its red cousin ― from the Kenai Peninsula in Alaska to Northern California. It grows well in cool, wet climates, and it grows slowly. This slow growth is responsible for its tight grains. It easily resists splinters, insects, and acid. It has virtually no smell, and it is also used in other products beyond cedar shake roofs.

How Long Does a Cedar Shake Roof Last?

Cedar has been used for centuries, and in fact, 5000-year-old tools made of red cedar have been found in North America. Cedar was also used to build the Temple of Solomon in ancient Jerusalem.

Most roofs were built using wood up until the last century when asphalt made its roofing debut, and sadly, asphalt roofing is now the norm.

Cedar shake roofs have a life expectancy of around 30 years, so long as they are properly installed and professionally maintained. Maintenance on cedar shake roofs should generally be done every two to four years to keep that life expectancy as high as possible.

What are the Types of Cedar Shake Roofs?

The various types of cedar shake roofs are dependant on how the tree was cut. There are three types:

  1. Edge grain cedar shake. This type is cut perpendicular to the tree’s rings. The grain is very tight, making the wood more stable. It goes by various names, such as quarter-sawn, vertical grain, radial grain, and rift sawn. Edge grain cedar shake roofs are less vulnerable to the elements, including changes in weather and moisture levels.

  2. Flat grain cedar shake. This type of cedar shake is cut at less than a 45-degree angle to the rings. It’s not as durable as edge grain and it’s more prone to absorbing moisture, which can lead to shingle problems like curling and cupping.

  3. Slash grain cedar shake. This type is cut at more than a 45-degree angle to the rings, which creates wavy grains. This makes the cedar shake shingles more unstable. And natural weathering can lead to numerous problems like distortion, erosion, and splitting.

High grades of cedar shake, like premium and #1, are a more stable, longer-lasting option. They are also more resistant to normal wear and tear, erosion, and problems such as splitting, cracking, and twisting.

There are also a variety of cuts when it comes to cedar shake roofs: Taper-split, Taper-sawn, Straight-split, Hand-split. The cuts are responsible for the appearance of cedar shake roof shingles and it mostly comes down to the homeowner’s aesthetic taste. For instance, split shakes give a more multi-dimensional appearance, while sawn shakes are smoother looking.

Are Cedar Shake Roofs a Fire Hazard?

Before we answer that, let’s dig into performance ratings a bit. A performance rating cannot be confirmed by just a visual inspection. Therefore, these ratings are handled by the CSSB (Cedar Shake and Shingle Bureau) which might win you a trivia contest if you can remember that.

The CSSB puts cedar shakes through a rigorous testing process for wind, impact, and fire resistance.

FIRE RESISTANCE

Fire resistance testing measures how long a roof can withstand fire penetration. In order to give a rating, testing protocols measure the following:

  • Intermittent flames
  • Spreading of flames
  • Burning brand
  • Flying brand

Your local building codes may determine the class of cedar shake you will need for your roof based on your geographic location. Areas that are prone to wildfires require a Class A, for instance, while most multi-family residences and commercial buildings require a Class B.

WIND RESISTANCE

Wind resistance is determined by measuring the wind uplift of a roof. Wind uplift is created when the air pressure below the roofing system is higher than the air pressure above the roof. Whenever the wind blows over a roof’s surface, the air pressure directly above the roof decreases. 

If you live in an area where storms and hurricanes are common occurrences, knowing the wind resistance of whatever roof you’re thinking about installing would be wise.

IMPACT RESISTANCE

Impact resistance for cedar shake roofs is determined by measuring the impact of a two-inch diameter steel ball dropped from a height of 20 feet. Class 4 represents the greatest class of impact resistance. If heavy hail is common in your location, this is something you should consider when purchasing a cedar shake roof.

How to Install a Cedar Shake Roof

There are a lot of components to installing a cedar shake roof that has lasting power and can make it to the 30-year mark we mentioned earlier. 

It’s important to let bundles of cedar shakes acclimate to the local environment before installing them. You’ll need to use proper fasteners, nails, and you’ll need to space the cedar shake roof shingles properly, too.

All it takes is one or two missteps to create a situation where your roof’s life expectancy is a lot lower than it should be. For instance, how nails are used and spaced is important. The proper sheathing is important for limiting moisture penetration. A cedar shake roof that wasn’t installed properly can lead to poor ventilation, poor drainage, and other issues that can prematurely deteriorate a roofing system.

How to Maintain A Cedar Shake Roof

The good news is that cedar shake roofs don’t require much maintenance. Individual shakes can easily be replaced should one crack or come off. However, replacing that shake is something that should still be left to the professionals, unless future water leaks sound like fun.

To keep the integrity of your roof intact, repairs should be made by those who know what they are doing. A periodic roof inspection is also a good idea. As the saying goes, an ounce of prevention is worth a pound of cure.

You should keep tree branches trimmed; you don’t want them rubbing against the cedar shake roof shingles. And finally, avoid excessive power washing, as this can weaken the fibers in the shakes over time and eventually cause you headaches (and money) you’d rather avoid.

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