01
Evaluate the slate field
Look for broken, missing, sliding, delaminating or unusually weathered pieces and patterns of repeated failure. A few isolated repairs mean something different from widespread deterioration. Note whether previous replacement slates match the thickness and layout.
02
Inspect every transition
Valleys, chimneys, sidewalls, headwalls, ridges, hips, eaves, penetrations and built-in gutters are common service points. Record the metal type, condition, laps and visible repair coatings. Interior staining and attic conditions can help connect symptoms to exterior details.
03
Document before prescribing
The report should separate urgent water-entry issues, routine maintenance and long-term planning. Clear photographs and locations make proposals easier to compare. Avoid recommending full replacement solely because of age without evidence about the actual slate and assembly condition.