The answer to 'flashing curling shingles' is that curling or lifting shingles are often caused by issues with the roof flashing. Roof flashing is the metal or rubber material installed around chimneys, vents, and other roof penetrations to prevent leaks. If the flashing is damaged, worn, or improperly installed, it can allow water to seep under the shingles, causing them to curl and lift up.
Some common causes of flashing issues include poor installation, corrosion, or damage from weather and age. Symptoms may include visible gaps or cracks in the flashing, water stains on the ceiling or walls, and curling or lifting shingles. In some cases, the flashing may need to be repaired or replaced by a professional roofer. Homeowners can sometimes fix minor flashing problems themselves, but major issues or full roof flashing replacement is best left to the experts.