The roof plays an integral role in protecting a house and in so doing is exposed to ultraviolet radiation, extreme weather conditions, moisture, and the possible infestation of insects. Penetrating moisture and boring insects can seriously damage a roof’s structural members. An annual inspection of the roof, from both inside and out, should be every homeowner’s priority.
If your house has an unfinished attic, inspect the inside of the roof armed with a good source of light. In general, you are looking for any sign of a leak, insect damage, or structural sagging. Water stains on interior framing may be a sign of weakness in the roofing material. Check the roof sheathing, which is a felt-like material hung between the rafters.
Carefully inspect the flashing, or the areas on the roof where there are joints, such as at dormer windows, at vent stacks, or where roof planes meet. Pay special attention to openings in the roof such as plumbing vents and chimneys; water could be entering around them. If your roof is finished with slate or clay tile, sunlight will be revealed through any cracked or broken tiles.
If you are uncomfortable on a ladder, inspect the roof from the ground, using a pair of binoculars.
Check for missing, curled, or cracked asphalt shingles. Look into roof gutters or under gutter downspouts for excess granule deposits, a sure sign of deteriorating shingles.
Misaligned slate or clay tiles will stand out against the straight lines of the others. Differences in color are also a sign that a tile has become dislodged or is loose and has shifted position.
Inspect a wood-shingled roof from the ground, checking for cracked or broken shingles. If you go onto the roof, be particularly careful not to inflict more damage, since wood shingles become more brittle with age. Shingles are more pliable after a good rain, but this will also make the roof more slippery.
On roofs of all finishing materials, inspect flashing at vents, wall joints, chimneys, plumbing stacks, dormers, skylights, along rakes and eaves, and at any valleys. Make sure the seal of roofing cement or caulking at the edge of the flashing material is intact. Flashing material, usually galvanized metal — and the compound that seals it –prevents water from penetrating the house along joints and should be frequently inspected and maintained. Inspect all areas where the flashing material meets brick to ensure that mortar has not separated from metal flashing.