Finding where the water actually gets in
Water travels along the underside of the deck and down a rafter before it shows up as a stain inside, sometimes several feet from the real entry point. We start in the attic whenever we can get up there safely, looking for dark streaking on the sheathing, wet insulation, or frost in winter, and we follow that trail back to the spot on the roof where the water is actually coming through.
Only after that do we go up on the shingles and look at what is above the traced point. It is usually a handful of things: a nail that backed out and lifted a shingle, a cracked shingle from wind, a plumbing vent boot that has dried and split in the sun, or flashing around a chimney or wall that has pulled loose.
Flashing and vent boots
Vent boots take the worst of the sun and the cold up here, and the rubber collar around a plumbing stack tends to crack within a decade regardless of the shingle brand. We replace cracked boots outright rather than caulking over the split, since caulk on a moving joint fails again within a season.
Chimney and wall flashing gets rebuilt with new step flashing and counterflashing rather than a bead of roofing cement smeared over the old metal. Cement patches buy a year, maybe two, before the freeze-thaw cycle cracks them again, and by then the deck underneath has usually started to soften.
Shingle repairs in cold weather
Shingles get brittle below freezing, which is most of a Minot winter, so a repair that cracks the courses next to it turns one leak into three. We schedule shingle repairs for a mild stretch when we can, or we warm the shingles before working them, because a repair should not create the next callback.
Wind-lifted sections get checked further than the obvious lifted shingle. If the wind pulled one loose, the nails around it were often set too high to begin with, and we check the whole slope rather than resealing one tab and moving on.
When a repair is not the honest answer
If we get up there and find cracked shingles across most of the roof, nail heads exposed in multiple courses, or a deck that flexes underfoot, we say so. Patching a roof that has reached the end of its life just delays the same conversation and costs you money twice.
We would rather tell you the repair will not hold and lose the small job than take the money and have the same stain reappear once the next storm rolls through the valley.