Roof inspection
On a slate roof, an inspection is not a formality — it is the thing that decides between keeping what is there and replacing for many times that. Nowhere else in the trade does an hour of looking move a number that far.
When it pays here
Before buying, above all. The housing in this valley routinely predates any record anyone kept, and on a slate roof the visible material tells you almost nothing about the fasteners holding it or the deck beneath. A buyer without an inspection is guessing at one of the largest numbers in the transaction.
Before deciding what to do with a slate roof, second, and this is the case unique to this region. Repair, replace in kind, or change material entirely: the three answers are separated by an order of magnitude, and only a proper look settles which one applies.
And after a winter that left ice at the eaves. Damage from that is at the edge and under the covering, which is precisely where nobody looks from the ground.
What a real inspection covers
It starts in the attic, because on old framing the deck and the rafters tell the truth about both water and weight. Spaced sheathing, previous repairs, staining, and whether the structure has moved under a century of slate.
Then the roof itself, walked where it is safe to walk and examined properly where it is not. Slate is not walked casually: a crew that treats it like shingle will break pieces while inspecting it. Then the valleys, the party wall junctions, the chimney, and the rear section that nobody sees from the street.
What it costs and what it saves
It costs a small fraction of what it informs, and it moves decisions many times its size. Buyers use it to negotiate, owners use it to time work on their own calendar rather than the roof’s, and anyone with slate uses it to find out whether they are sitting on a liability or on fifty more years.
Quick answers
- The slate looks fine from the street. Is there anything to see?
- Usually yes. Slate fails at its fasteners and at the valleys long before the field looks bad, and neither is visible from the ground.
- Can any roofer inspect a slate roof?
- Any roofer can look at one. Fewer can walk it without breaking it, and fewer still can tell you whether the structure will carry a replacement in kind.
- Is a drone inspection enough?
- It is a good start and a poor finish. The attic, the fastener condition and the rear roof tell the parts of the story a lens cannot reach.
- What kind of finding fails an inspection on a slate roof?
- Fasteners that have rusted through even where the slate itself is intact, spaced sheathing left unaddressed, a party wall flashing that was sealed rather than rebuilt, and slipped or missing pieces in a valley. On slate the fasteners usually give out before the stone does, which is why a report built from the street misses the finding that matters most.
- Why do I keep getting calls about a free roof inspection?
- Those calls almost always come from a canvassing list rather than from anyone who has been up on your roof, and older neighborhoods with visible slate get targeted more than most. A real inspection is one you scheduled yourself and that ends with a written report and photographs, not a pitch delivered on the spot.
- 1 The ridge. The highest course, and on slate the one most often reset by hand.
- 2 The field. Quarry slate on the old houses, asphalt on everything since. Two very different clocks.
- 3 Valleys. Where leaf litter settles, and where a slate roof usually ends its life.
- 4 Wall flashing. The party wall of a row or twin, rising through a roof two houses share.
- 5 Penetrations. Holes cut on purpose. When access is awkward they get sealed instead of rebuilt.
- 6 The overhang. Where meltwater from a warm attic reaches cold framing and stops.