Roof Inspection Procedure

A roof inspection is a structured examination of a roof to record its condition, find defects and identify the causes of leaks. Inspections are carried out by roofers before quoting, by home inspectors during property sales, by insurers after storms and by building owners as routine maintenance. The scope and access methods differ: a general home inspection may be done from the ground or eaves, while a roofing contractor or consultant usually walks the roof where it is safe.

Scope of a home inspection

The InterNACHI Standards of Practice, widely used in North America, require an inspector to inspect roof coverings, gutters and downspouts, vents, flashings, skylights, chimneys and other penetrations and the general roof structure from accessible openings. Inspectors must describe the roof covering type and report observed signs of active leaks. They are not required to walk on the roof, predict remaining service life, perform water tests or confirm that coverings were properly fastened.

Typical procedure

1. Plan and set up safely. Review history and previous repairs, check weather and arrange fall protection and ladder access.
2. Ground and perimeter. Look at roof lines for sagging, check gutters, downspouts and fascia, and view slopes with binoculars or a drone.
3. Roof surface. Check the covering for missing, cracked, curled or slipped units, granule loss, blisters, splits, open seams, ponding and loose fasteners.
4. Flashings and penetrations. Examine valleys, step and apron flashings, chimneys, skylights, vent boots and edge metal.
5. Drainage. Confirm gutters, scuppers, drains and downspouts are clear and correctly sloped.
6. Attic or interior. Look for stains, daylight, damp insulation, mould, frost and ventilation problems.
7. Record. Photograph and mark defects, then summarise findings and recommendations.

Common problem areas

Canadian guidance lists the following as frequent problem areas: separated or deteriorating flashings at penetrations; blisters, fishmouths, ridges and alligator cracking on bituminous membranes; scouring of ballast or granules; splits at gravel stops; popped fasteners and poor seams on single-ply membranes (checked with a seam probe); poorly installed valleys and roof jacks; blocked eavestroughs; condensation stains; and backed-out fasteners on shingle and exposed-fastener metal roofs.

Frequency

Canadian guidance recommends repairing potential problems as soon as they are found and setting up a preventive maintenance schedule. Inspections after major storms, and before buying a property or renewing insurance, are also common practice.