How to read a roof from the sidewalk

You do not need a ladder to know most of what a roofer will tell you. Stand across the street on a dry, bright morning with a pair of binoculars and work from the top down.

Start at the ridge

The ridge should be a straight line. A dip in the middle usually means the decking has taken on water. Caps that sit crooked or show their nails are the first place wind gets in.

Then the slopes

Look for shingles that curl at the corners, sit darker than their neighbours or have slipped out of line. One or two is a repair. A pattern across a whole slope is the roof telling you its age.

Finish at the edges

Gutters that hold granules, stains under the eaves and flashing that has pulled away from a chimney are all visible from the ground, and all cheaper to fix this year than next.