After a Middle Tennessee Storm the Roof Gets Fixed and the Wall Stays Wet

March through May: what the wind actually does to a roof

Severe season here is spring, with a second round in late fall. The damage that matters for moisture is rarely the hole everybody photographs.

Wind lifts shingle tabs and they reseal crooked. Hail bruises the mat without opening it. Rain driven sideways gets past the rake edge, under a ridge vent or into a valley. From there water does not fall straight down. It runs along the underside of the sheathing, follows a rafter, reaches the top plate and goes into the wall cavity, which is insulated and dark and sealed on both faces.

By the time a stain shows on drywall it has been somewhere else first. A ring in the top corner of a bedroom on the west side of the house is usually a roof story, not a plumbing one.

Gutters take a beating in the same storms. A downspout knocked off its strap, a section pulled loose by a limb or a gutter packed with the debris the wind stripped out of the trees all end the same way: rainwater falling straight down at the foundation for the rest of the season.

Interior damage from a storm is often delayed by the ceiling itself. Drywall holds water for a while before it stains, so a leak that started during the storm can take a couple of weeks to announce itself, by which point the roofer has been paid and everyone has moved on.

The same storm hits the crawl space from underneath

Rutherford County clay does not drink fast. A heavy rain runs off the surface, collects in the low corner of the yard and sits against the footing for days after the sky clears. Under the house the dirt goes dark, water pushes up under the vapor barrier and floats it out of place. A line shows on the block piers.

One storm, two paths into the same house, neither connected to the other. The roof path gets repaired because it is visible from the street. The crawl space path is visible from nowhere at all.

The crawl space also recovers more slowly than the roof does. A shingle is replaced in an afternoon. Saturated clay against a footing gives up its water over weeks. It gives that water up into the crawl space, because the crawl space holds the driest air anywhere near it.

June and July: humidity finishes what the storm started

A vented crawl space takes in whatever the outside air is doing. In a Middle Tennessee July that means warm wet air moving across joists that are cooler than it is, so the air gives up its water on the wood. Nothing under there dries in summer. It gets wetter.

The same season works on the roof damage. Wet insulation in a ceiling does not dry upward. Wet sheathing behind brand-new shingles does not dry either. The top plate, the framing and the paper facing on that batt stay damp into the hottest part of the year, which is precisely when growth gets moving.

So the odor arrives late. That is the part people find hard to believe: the storm was in April, the smell is in August. Nobody puts the two together.

It shows up in the insurance conversation too. By the time anybody looks, the claim is months old, the roofer is finished and the cause has to be argued from photographs that were never taken.

What dries on its own and what does not

Some things recover without help. A wet exterior wall that gets sun on it, an open porch ceiling, siding that got soaked: those dry to the outside within days once the weather turns.

The list that does not dry on its own is the one worth writing down. Insulation inside a closed ceiling. Sheathing under new shingles. A top plate sealed between drywall and siding. A subfloor with plastic-backed batt insulation under it. Any of those hold water for months, because both faces of the assembly are closed and nothing moves air through them.

That difference explains why the storm damage that looks worst from the street is rarely the part that grows anything. The visible wet dries. The hidden wet waits for July.

Where does it show up inside?

A ring where the ceiling meets an exterior wall rather than in the middle of the room. A stain across the head of a window trim. Paint blistering in one corner only. Hardwood cupping along a single exterior wall and nowhere else. A floor that gives slightly near a bathroom. A duct boot that beads with water. A return that smells for the first minute after the system starts.

Under the house: batt insulation fallen off the subfloor, plastic slid into a pile, rust on the duct straps.

None of those prove anything. They are the places to put a meter.

What to do while the roofer is still on the property

Photograph what you can from the ground while the damage is fresh, including the yard. Where water stood after that storm is where it will stand after the next one. That photograph is worth more later than any description you can write from memory.

Ask for photographs of the decking with the shingles off. Ask whether any sheathing was dark or soft. Ask whether the underlayment was wet when they pulled it.

If ceiling drywall got wet, the insulation above it is wet too. It will not dry on its own inside a sealed cavity. That is the call to make while there is still scaffolding in the driveway rather than months later.

Walk the gutters after the crew leaves, especially on the back of the house where nobody looks from the street. Reattach or extend anything the storm moved. Water landing at the foundation is the second half of this problem.

Then go look at the crawl space the same week. Dark dirt, floated plastic, a mud line on a pier: all of it is easiest to read while the memory of the storm is fresh. Repairs to the outside of a house do not dry the inside of it. That is the whole lesson of the season around here.