Also bear in mind that wood shingles, metal, slate and tile do not offer the grip provided by the granular coating on asphalt shingles. Some shingles might be brittle and could break underfoot. In most cases, it's best to leave a close inspection to a pro, and make your diagnosis from a safe vantage point. Although northern slopes generally take the brunt of wind and rain, south-facing slopes often break down first because of accelerated aging caused by the sun's rays. Wood shingles and shakes Longevity varies with all types of roofing depending on the installation, quality of materials and exposure.
Weather works on wood in two ways, causing deterioration from wetness and dryness.
In damp locations, where the roof is shielded from wind and sun, wood may rot in 15 years or less. The process accelerates when moss grows on the roof because the spongy patches hold moisture next to the wood even on dry days. Eventually, the drying causes cracking, which can split a shingle into two or more pieces, often in line with the nail holes. In the next stage of deterioration, shingles start to curl and no longer lie flat on the roof. You can repair isolated damage by removing split sections and installing new shingles.