Q & A - Shake Roof Repair

How and when should I have my shake roof repaired?

This is a common question asked here at AskARoofer. Most shake roofs start to fail after 15 years. Some sooner, some later, but most start to show age when shakes curl, split and blow off, leaving missing shakes. Cedar shakes can been installed over skip sheathing and solid decking. The skip sheathing was typically used so the roofing system could breathe. This would happen because of the interlaced shake felt. Interlaced felt was 30 pound or what is called #30 and was 18 inches in width. It is laid at 10-inch courses thus giving the roofing felt an eight-inch headlap. Air actually will flow through the laced felt and shakes. This would make a breathable roof, cooling down the attic in the hot summer months. In the winter this would help dry the wet soaked cedar shakes. Solid decks used plywood or plank wood without spacing cannot breathe the same as skipped sheathing. I have found these types of roofs failed sooner than the skip sheathed ones because the water-logged shakes would rot, loosen and fall out or get blown off.

Repairing a shake roof by blind nailing

The photo above is a heavy shake roof and 23 years old. It has no missing shakes and minimal curling. I did not walk on this roof and you cannot see but the wood fibers are aged and would turn to dust under every step made on this roof. It may not leak now but extreme damage would be done to this roof trying to repair it. It is too far gone and was advised to the owner not to let anyone walk on this roof until it was totally replaced. This photo shows a roof that is about 10 years old with a split shake being repaired. The shakes are still hard and strong enough to walk on without too much damage.

Using two nails placed high at the butt of the next course (see the red arrows), the shake should be nailed about an inch low, then be tapped upwards and aligned with the other shakes and covering the nail heads. This will take some skill and should be done on solid decks only or when the skip sheathing has a 1×4 in the nail zone needed.

Covering the nails will help keep the nails from backing out and looks professional. I have repaired many cedar shake roofs over many years just like this but resist doing them only when in desperate need or to fix a leak. It is my belief more damage is done doing repairs on a shake roof than if it is left alone. Again if the roof is leaking it is needed. Most homeowners may not know but the interlaced felt is a water-tite roof in itself. If there aren't any holes or breakage in the felt, it will shed the water down to the next course of shakes and off the roof.

Tip of the day: When installing the felt on a new shake roof, instead of using the 18-inch rolls, for a little extra buy 22-inch rolls. This automatically double felts the roof with a two-inch headlap, making it a better roof.

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