With asphalt shingle roofs, the primary water barrier is the tarpaper or “tyvek” type roof barrier sometimes used today, and is the first layer placed against the roof decking. The asphalt shingle protects the water barrier from exposure to sunlight and physical damage (hail, windblown tree branches, etc). It also provides some protection from a hard rain, but it’s not the primary barrier.
Hail damage to the shingle causes loss of granules on the shingle. The shingle then degrades and cracks over a period of time. When the cracks occur in the shingle, it’s only a short time before the water barrier cracks and fails.
I had some hail damage from a storm last week, and this past Saturday I found extensive “dings” on the roof where the granules were knocked loose from the ahingles, similar to the photos above. I was wondering if I could replace the granules, and I found the answer here. At best, it’s only a short term repair.
Looks like I will be calling my insurer tomorrow. It’s a pity. The roof had a 40 year manufacturer warranty, and is a little over ten years old. The warranty protects against material defects, not hail damage.