What Really Kills Most Cedar Shake Roofs
Forget hail damage, animals, moss, rot, ice and wind. The sun is your roof’s main enemy.
If I’ve said it once, I’ve said it a thousand times, the purpose of all of the wood on your roof IS NOT to keep water out of your home. Its’ purpose is to protect the tar paper below, which is the stuff that actually keeps the water from wrecking your ceiling (and your day). As long as the tar paper on your roof stays intact water will stay where it is supposed to be; outside. The roof shown here appeared fine from the ground. In fact, this homeowner received an estimate from a roof washing ‘expert’ that suggested wood cleaning and wood preservation. Bad idea (and bordering on criminal if you ask me).Still, I guess I can see how a novice might think this roof was worth saving. After all, there was no cupping or curling, no missing shakes, no wind or hail damage, no rot caused by organic deterioration, nothing dramatic whatsoever. Upon closer examination I immediately knew it needed to be replaced. Why? Open keyways.
Keyways:
The spaces between the shakes are called ‘Keyways’. In some ways they are the achilles heel of your cedar roof system because the shake in the course below is at its’ thinnest point at the top of the keyway. In the roof shown here there are no less than 34 open keyways in just this small area. The cost to replace that many shakes when factored across the entire roof made the concept of roof repairs unwise. The only option for wood roofs with numerous open keyways is replacement. Open keyways are the number one reason cedar roofs fail. Of the thousands of roofs I’ve inspected this problem accounts for at least 90% of the roof failures with the other 10% comprised of organic rot, fastener failure and installation errors.