If you find that 20% of more of the slates on your roof need to be replaced due to damage, it’s best to replace the entire roof, as it’s ultimately less expensive than paying to fill in all of the broken or lost slates.
#2:
Flaking: Also called delaminating, flaking is a common sign of slate that’s past its useful life.
#3:
Powdering: If you notice that your slate has a powdery-looking surface, the roof will soon need to be replaced.
#4:
Porousness: Even if your roof looks like it’s in good condition, it may be worn beyond repair. If you tap the slate’s surface with your knuckles and notice a dull thud, the material has likely grown porous and should be replaced.
#5:
Moisture damage: When slate absorbs too much moisture, it becomes soft or brittle and can begin to rot, resulting in moisture damage in your home’s rafters or attic.
Slate roofs are tricky to deal with and can cause major issues upon removal. They need to be removed with care, safely and professional manner.