You may glance up at the roof once in a while but it’s not part of the house that grabs attention— until there’s a leak. An inspection can catch problems before that happens, and also help you choose the right time to reroof. That can be a tough call unless you have a close look: too soon and you waste years of service from the singles; too late and reroofing can mushroom into an expensive sequence of stripping what’s there and starting from scratch.
*On the roof or not. A close look provides better feedback than checking from the ground or even from a ladder along the eaves. But so-called walkable roofs (you don’t need scaffolding) may feel comfortable to some and scary to others. The rule is to follow your instincts. If you’re not comfortable there, don’t go there. If you make the climb, stay off wet roofs and wear non-slip shoes in any case. Avoid asphalt roofs midday under full sun (they can get gooey) and roofs where the singles (whatever the material) are loose.
*Checking choke points. They’re usually easy to spot, like the joint between chimney flashing and a sloping roof that piles up with leaves and pine needles. Whatever is stopping them, often displaced flashing, needs to be fixed to keep the roof free-flowing and prevent ice dams in winter. The same goes for gutters. You have an old wire basket that traps leaves and blocks the downspout flow? Remove it and either try another screening system or plan to clear the gutters more often.
*Revisiting repairs. A part of the roof that leaked before is a prime candidate to do it again. That’s because most repairs are stopgap measures. Instead of tearing out two layers of flashing, chiseling out old mortar, and resetting new copper along a chimney, you get a strip of aluminum with a smear of roof cement. Worse yet are repairs on sloped roofs made with roof coating, a runnier version of roof cement that leaves only a thin coat of asphalt over leaks.
*Monitoring shingle life. Thin, lightweight shingles wear out sooner and multi-layer, heavyweight shingles last longer, but typical installations on most sloped roofs last about 20 years. Of course, longevity also depends on the surroundings. Free-flowing roofs exposed to air and sunlight do better while roofs in shade and covered with mold and moss do worse. But whatever the lifespan, asphalt shingles generally deteriorate in three stages.
1. Surface granules start to wear away, creating dark patches where bare asphalt shows through. If you don’t see the patches you can spot the granules collecting at the ends of downspouts. Leaks are unlikely at this stage, but as more granules erode, shingles will dry out, crack, and may have to be replaced before the entire roof is redone.
2. Shingle sections exposed to the weather, called the tabs, become brittle and start to curl. The roof takes on a waffled appearance instead of lying flat. That makes it more likely to leak, specially in winter and any place where debris piles up and traps water. Reroofing is still an option. But unless you strip the roof and start from scratch, each curled tab should be broken away and patched. Otherwise the new roof will reflect the waffle pattern and the tabs won’t seal out the weather.
3. Instead of finding granules in the gutter system, you find chunks of shingle tabs— so brittle and curled that they break off. That exposes nail heads and a direct route for water through the overlapped layers of protection into the house. At this point most reroofing jobs start by stripping the roof, which drives up the price with extra labor and carting fees.