What Gets Checked
A roof inspection that does not include the attic is half an inspection, and in Toronto the attic is where the answer usually is.
Short answer
A proper inspection covers the roof surface, the flashings and penetrations, the eave and the drainage, and the attic from inside. The attic is where heat loss, blocked venting, moisture staining and previous leak evidence are visible, and those are what predict the next five years.
On the roof
Shingle condition: granule loss, curling, cracking, missing tabs, and whether the different exposures have aged differently.
Valleys, which are the highest-volume water path and the most common failure.
All flashing: chimney, sidewall and step flashing, valley metal, vent boots, skylight perimeters.
Penetrations and anything added after the original roof — a satellite mount, a new vent, a conduit.
The eave and the drip edge, and whether water can get behind the fascia.
And the ridge and the exhaust venting, with the intake checked from below.
And the attic
Underside of the sheathing for staining, frost history and mould. Nail tips for rust. Insulation depth, coverage and whether it is blocking the soffits. Bath fan terminations. Pot lights and the hatch for air leakage. Daylight at the eave. That is where a Toronto roof inspection earns its fee.
What the report should say
Remaining life as a range rather than a number, with the reasoning.
Specific defects with locations and photographs.
Priority: what needs doing now, what needs doing within a year or two, and what is monitoring.
The ventilation assessment, explicitly, because it is the biggest lever on remaining life.
Any evidence of past leaks and whether they are active.
And a clear statement of what was not accessible, because an inspector who could not get into part of the attic should say so rather than imply coverage.
When to get one
Before buying, as a separate exercise from the general home inspection, which rarely covers a roof in this detail.
After a significant wind or hail event, before dealing with the insurer.
At around fifteen years on an asphalt roof, so the replacement can be planned rather than forced.
After any ceiling stain, which is a leak somewhere whether or not it is still running.
Before a renovation that will make the roof harder to access.
And in the fall rather than mid-winter, because the roof can actually be walked and the attic conditions are readable.
Common questions
Should the attic be included?
Yes. In Toronto the attic is where the answer usually is.
When is the best time?
Fall, when the roof can be walked and the attic conditions are readable.
Is a home inspection enough?
Rarely at this level of detail on the roof. Get a separate roof inspection when buying.