How often should you inspect your roof?

Catching a loose shingle early avoids a five-figure roof or water-damage bill.

Water entering a roof rarely appears directly below the entry point. It travels along rafters and shows up somewhere else entirely, by which time it has been wetting timber and insulation for a while. Rot, mould and ruined insulation cost far more than the original repair.

1. Start inside the loft. On a bright day with the lights off. Daylight through the roof deck shows you exactly where the gaps are.
2. Look for staining on rafters and sarking. Water marks on the underside of the sheathing or along rafters, dark streaks or mould all indicate past or present water ingress.
3. Check the insulation is dry and evenly laid. Compressed or damp insulation is both a symptom and a further problem.
4. Go outside with binoculars. A maintenance check of a pitched roof can usually be done from the ground or from a ladder at the roof edge. Look for slipped, cracked, curled or missing tiles and shingles.
5. Concentrate on the penetrations. Flashings around chimneys, vents, skylights, hips and valleys are typical places for leaks to start, more so than the open field of the roof.
6. Check the ridge and the verges. Look for loose ridge tiles and cracked or missing mortar bedding on tiled roofs.
7. Look at the gutters for granules. On asphalt shingles, sand-like granules collecting in the gutter mean the shingles are shedding their protective surface. Curling or splitting shingles are evidence of deterioration.

• Any stain on an upstairs ceiling, however small or old-looking
• Granules accumulating in the gutters
• Daylight visible through the roof from inside the loft
• Slipped or missing tiles visible from the ground
• Sagging along the ridge or between rafters, which is structural and urgent
• Moss growth heavy enough to lift tile edges

• Climbing onto the roof to inspect it. NRCA does not recommend that homeowners walk on roofs, and you can break the tiles you are inspecting
• Only looking after a leak appears, by which point the damage is done
• Ignoring flashings and focusing on the tiles, when flashings are a typical leak point
• Pressure washing a roof to remove moss. The Asphalt Roofing Manufacturers Association says never to pressure wash asphalt shingles because it strips granules and shortens the life of the roof

• Inspect after any severe storm, hail or high wind event regardless of schedule
• A roof nearing the end of its expected life justifies closer attention and a professional look
• Overhanging trees drop debris that needs clearing from valleys and gutters, and encourage moss
• Hail can cause damage that is hard to judge from the ground, so get a professional look after a significant hailstorm

Any repair work, anything requiring you to walk on the roof, and any structural sagging. Also get a professional inspection before buying a property, and after significant hail.