Wood shingles and shakes go back to colonial times when they were the roofing system of choice. They are typically made from Red Cedar. The shingles are sawn uniformly, in a few standard sizes. Shakes are split, creating a more rustic appearance, but that does require an additional course of roofing felt between each layer to help prevent leaks. Wood roofing can be installed on roofs that are 3:12 and over. They are also light weight, so they can be installed on virtually any structure.
The benefits of cedar shake shingles:
The big benefit these systems offer is their visual appeal. Few things are more attractive than their rustic appearance. They are especially beautiful when they are still fairly new, but have weathered into a natural gray. The look is so attractive that all the asphalt roofing manufacturers have architectural shingles made to look like “weathered wood”.
The problems with cedar shake shingles:
The main disadvantage with wood roofing is the inherent fire hazard. I saw an aerial photo of a neighborhood in California that had been struck by a brush fire. Every home had burnt to the ground except one. They all had wood roofs except for the one left standing, which had a tile roof. Brush fires aren’t the only fire hazard for wood roofs… Sparks from a wood-burning stove or fireplace have started many wood roofs on fire.
Insurance companies hate wood roofs, as they have been burnt so many times insuring them. Now days, they either won’t provide coverage at all, or want enormous premiums to do so. The fire risk is so great that many areas have outright banned wood roofing, despite manufacturer’s attempts to make it more fire resistant. I’m a tad dubious on how fire-resistant it actually is. Here’s why I say that…
The owner of a roofing company I used to work for liked to save dump fees by burning trash that accumulated around his warehouse and office. Almost every day he had a bonfire, burning up old pallets and such. I had just returned from cleaning up my first wood roofing project and had some scraps of the “fire-resistant” material in the back of my truck. It occurred to me to test their fire-resistance by throwing them on the bonfire. I was amazed at how fast they burst into flames.
Other disadvantages of cedar shake shingles include:
They can be extremely hazardous to walk on when wet, which they might just be when you are chasing a leak.
Wood requires periodic cleaning and treatment to keep it free of fungus.
Wood tends to curl and split, creating leaks. This is a particular problem in places like Florida, which has lots of rain, followed by lots of sun.
Cedar shake shingles are expensive. On top of a labor intensive manufacturing process, is the shipping expense. The last ones I bought here in Florida were trucked all the way down from Canada.
Installing wood shakes and shingles is labor intensive. Each one covers a fairly small area and has to be individually positioned and installed with two nails. And great care must be taken to select or cut each piece to avoid exposing nails in the course below. I once replaced a wood roof that was only three years old because the roofer screwed this up. He left exposed nails (and leaks) all over the place.
This work is somewhat of an art and is not a good do-it-yourself friendly project. I like roofing systems that are simple enough for a homeowner to successfully install himself if need be. These roofing systems also have a fairly short life span… typically 15 years or less depending on the climate. Combine that with high repair and maintenance expense, and you have huge lifecycle costs.
My opinion of cedar shake shingles:
They may have been the best choice a century or two ago, but their time has come and gone. I love the look, but the fire hazard alone is a “fatal flaw” that rules them out in my book. You can do better… for less money.
But if you choose cedar shake shingles anyway, go with a contractor who specializes in them. The correct flashing details and nail placement are critical with this system. You want a guy who does it all the time. And be sure to get the type treated with fire retardant, for whatever that’s worth. At one time I think they just sprayed it on, but the kind to get is the type where fire retardant is pressure treated deep into the wood.
You are better off going with wood shingles than shakes as they are easier to flash effectively. Also, inquire about a premium underlayment. That will help the system be more forgiving to any water that gets under the wood roofing.