The answer to 'my underlayment is failing' is that the underlayment, which is the layer installed beneath the roof shingles, can fail for several common reasons. This can lead to leaks, water damage, and other roofing issues. Some of the most common causes include age, improper installation, exposure to the elements, and lack of maintenance.
Symptoms of a failing underlayment can include visible wear, cracks, or holes in the material, as well as water stains or leaks in the attic or interior of the home. If you notice any of these signs, it's important to address the issue promptly to prevent further damage.