A brown ring appears on a bedroom ceiling. It grows a little every time it rains hard. Somebody goes up, finds nothing obviously wrong above it, puts a smear of sealant on the nearest thing that looks suspicious, and comes down.
Six weeks later the ring is bigger.
This is the single most common way money gets wasted on a roof, and it is not carelessness. It is a reasonable assumption about water that happens to be wrong.
Water enters high and leaves low
A pitched roof is built to shed water in seconds. Shingles are small overlapping scales, and anything landing on them is gone almost immediately. So when water does get in, it does not get in through the middle of a shingle. It gets in at an interruption — somewhere the covering has to stop, turn a corner, or let something through it.
The list of interruptions is short and it is nearly always one of these:
- A valley, where two slopes meet and all the water from both of them is funneled into one line
- A chimney, which is a hole in the roof with masonry sitting in it
- A sidewall, where a roof dies into the side of the house — a porch roof into the main wall, a dormer cheek, a garage into the gable
- A pipe boot, the rubber collar around a plumbing vent, which goes brittle and splits from sun long before the shingles around it are worn out
- A ridge or box vent, letting weather in rather than air out
- A backed-out nail, which lifts the shingle above it a quarter of an inch and leaves a path
Once water is through, it does not drop straight down. It runs along the underside of the deck, or down a rafter, until it meets something that stops it — a nail point, a joint in the drywall, the metal box of a ceiling light — and that is where it appears.
So the stain marks the first obstruction, not the fault. On a shallow run the two can be a foot apart. On a long rafter bay they can be eight or ten feet apart, and on a different side of the room from where the water came in.
Sealing the roof directly above a stain is therefore a coin flip, and the fact that it sometimes works is what keeps the habit alive.
How to actually find it
The attic tells you more than the roof does, and it is free to look.
Pick a dry day, take a good flashlight, and look at the underside of the deck, not at the insulation. You are looking for three things:
- Dark staining on the plywood or the boards. Old water leaves a tide line.
- Rusted nail points. Hundreds of nail tips come through the deck. The ones that are rusty are the ones that have been wet, and they map the path.
- White or gray crusty deposits. That is mineral left behind as water evaporated — a sign of slow, repeated wetting rather than one storm.
Follow the staining uphill. Water runs downhill, always, so the highest wet point in the attic is the closest thing you have to the entry. Then go outside and look at what is above it. Nine times out of ten there is an interruption there, and it is one of the six on the list.
One more piece of evidence costs nothing and is worth a great deal: which direction was the wind in when it leaked? A leak that only shows in driven rain from the west is almost always a flashing or sidewall problem, because the water is being pushed sideways under a lap that works perfectly well in vertical rain. A leak that appears in every rain is an open path. A leak that turns up a day after the weather has passed is water being held somewhere and tracking, and where it is being held matters more than where it is dripping.
Tell whoever comes out those three things — where the stain is, how fast it grows, and the wind direction — and you have cut the diagnosis in half before anybody gets a ladder off the truck.
The thing people in Lansing get wrong in February
Around here there is a second cause that behaves exactly like a roof leak and is not one.
An ice dam forms when heat escaping into the attic melts snow on the upper part of the roof, the meltwater runs down to the cold overhang, and refreezes there into a ridge of ice. Water then backs up behind that ridge and sits on the roof. A pitched roof is designed to shed water, not to hold it, so water standing four inches deep behind a dam finds its way under the shingles and into the house.
The reason this matters is that the roof is usually fine. The fault is heat and air leaking into the attic, and the fix is insulation and air sealing, not shingles. Every winter somebody in this county pays for roof work that was never going to help, because the symptom arrived through the ceiling and the ceiling is what they could see.
If your leak shows up in late January and nowhere else in the year, start there.
When it is the roof, and when it is the roofline
The other regular surprise from a first visit is that the roof is sound and the problem is the edge of it.
The roofline is the fascia, the soffit, the roof returns where the eave meets the wall, the trim, the flashing behind the gutters, and the gutters themselves. It takes more weather than any other part of the exterior and it is the part nobody looks at. Fascia goes soft behind a gutter that has been overflowing for two seasons. A roof return rots out where the eave dies into the wall and nothing sheds there. Step flashing was never fitted where a lower roof meets a sidewall, or it was buried under a later layer and now does nothing.
Every one of those looks exactly like a roof leak from inside the house, and none of them needs the roof touched. A great deal of what we are called out for turns out to be this, and it is a much smaller job than the one people are braced for.
What a repair can and cannot do
A roof is repairable far more often than people expect, because the field of it usually outlives the details attached to it. Flashings, boots, valleys and penetrations fail first. Replace those properly and the roof goes on working.
Where repair stops being the right answer:
- The deck underneath is soft. A watertight covering over wet sheathing is a patch on top of a problem it cannot reach. The decking inside the opened section gets replaced, and you should be shown photographs of it before it goes back over. Nobody should accept a roof closed up over something they were never shown.
- The movement is structural. A sagging ridge, a wall that has spread, a roof plane that has gone visibly out of line — that is an engineer's question and not a roofer's, and anybody who offers you a confident opinion on it over the phone is guessing.
- It has simply run out. Covering reaching the end of its life, curling at every edge, granules gone — at that point a repair buys you a season and you would rather know.
And one trap worth knowing: if your covering is still inside a manufacturer's system warranty, having anyone other than one of their certified installers work on it can void what is left. Check before anybody starts, not after.
A straight word about scale
We do roof work, and it is worth being exact about which roof work, because vagueness here wastes everyone's time.
Repairs and section work. Leaks traced and fixed. Flashings, valleys, chimney and sidewall details, pipe boots, ridge and box vents. Storm damage. A porch, breezeway, garage, dormer or patio roof taken back to sound deck and rebuilt properly — this July we replaced a patio roof complete, and a breezeway roof at a house on Snyder Road, structure and membrane and shingles and the flashing back into the house, starts this week. Plus all of the roofline, which is years of invoiced work.
Not stripping every slope on a two-story house end to end. That is a bigger operation than our record supports, and you would be better served by an outfit that does nothing else. You will be told that at the first visit rather than in the middle of the job.
We also do not do torch-applied work, at any price. Open-flame roofing is a leading cause of fires on construction jobs, it needs a hot-work permit and a fire watch kept after the crew leaves, and the risk sits with your building rather than with whoever is holding the torch. Self-adhered material does the same job.
Four things to do today if it is leaking now
- Photograph the stain with the date visible in the frame, and photograph it again after the next rain. How fast it grows is the most useful single fact you can hand anybody.
- Look in the attic on a dry day, with a flashlight, at the underside of the deck.
- Put something under it and move what matters. A soaked ceiling comes down without warning.
- Stay off the roof. A wet or frosted slope is genuinely dangerous, and a roof that is already failing is exactly the one that will not hold you.
If it is actively running in and you have to do something, a tarp weighted at the ridge will hold it. Do not nail a tarp down — you are making new holes in the thing you are trying to keep water out of.
Haslett Handyman Company works across Lansing, East Lansing, Okemos, Haslett, Holt and the surrounding townships. Coming out to look at a roof is free and there is no trip charge. If you would rather know what you are dealing with before you spend anything, that is the visit to book.