Repair or Replace? How to Tell What Your Roof Needs

People usually ask about their roof the wrong way round. They start from how old it is, and age on its own decides very little. A twenty-year-old roof that was installed properly on sound decking with adequate ventilation can be in better shape than a twelve-year-old one that was nailed over an existing layer in a hurry. What actually matters is whether the failure is local or general.

Start in the attic, not on the roof. It is the safest place to gather real information and it tells you more than a walk around the garden does. Go up on a bright day with the lights off and look for daylight coming through the decking. Then look at the underside of the sheathing for dark staining, and press it in a few places — sound wood is firm and does not flex under a thumb. Staining in one bay near a chimney or a vent is a flashing problem. Staining spread across several bays, especially near the eaves, is a different and bigger conversation.

Then look at the roof from the ground with binoculars if you have them. You are looking for whether the surface is uniform. Missing or lifted shingles in one area, usually on the windward side or around a valley, points to a localised repair. Shingles that have lost their granules across whole slopes — the surface looks patchy and darker where the mineral coating has gone — is general wear, and patching one section of that is buying a year at a time.

Check the gutters while you are down there. A little granule loss is normal for the first year of a new roof and after that it should be minimal. A gutter with a sludge of granules in the bottom, every year, means the shingles are giving up their surface, and that surface is what protects the asphalt underneath from the sun.

Look at the flat details rather than the field of shingles. Most roofs do not fail in the middle of a slope; they fail where two planes meet or where something pokes through. Valleys, the flashing where the roof meets a wall or chimney, and the boots around plumbing vents are the usual suspects. A cracked vent boot is a genuinely small repair that causes a genuinely alarming ceiling stain, and it gets misdiagnosed as a dead roof more often than anything else on this list.

Finally, count the layers if you can see an edge. Two layers of shingles is common and legal in a lot of places, but it limits your options: you cannot add a third, and a tear-off of two layers is a bigger job than a tear-off of one. It also means nobody has looked at the decking in a long time.

If the trouble is in one place and the rest of the surface is even, a repair is usually the right call. If the granules are gone across whole slopes, the decking flexes underfoot, or you are finding stains in several places at once, a repair is a delay rather than a fix. To talk about which one you are looking at, message us on WhatsApp at (309) 336-9329 or send photos through the form on this site — though the attic check above is the part that has to be done in person.