Hail, roof leaks and attic mold in the Oklahoma City metro

Hail is a regular part of life in central Oklahoma, and the damage it does to a roof isn't always obvious from the ground. The National Weather Service's Norman office lists the May 16, 2010 storm as one of the most damaging and costly hail events in Oklahoma, with golf ball to baseball-size hail across northern and eastern parts of the metro and damage estimates over $500 million. On May 20, 1990, grapefruit-size hail broke windows and damaged roofs on the north and west sides of the city. On March 25, 2015, one supercell crossed Canadian, Oklahoma and Cleveland counties, with a tornado near Yukon, wind damage in southwest Oklahoma City and Moore, and baseball-size hail (NWS Norman). A roof that comes through a storm like that with a few cracked shingles or a dented vent can leak slowly for months, and the attic is where that water goes.

Why storm leaks turn into mold

A slow roof leak is about the best setup mold could ask for. Water drips onto insulation and the top of the ceiling drywall, nobody sees it, and the attic stays warm. The first sign in the living space is often a tan or brown ring on the ceiling, a sagging spot, or a musty smell in one room after rain. By then the decking, rafters and insulation above may have been wet many times. EPA lists the tops of ceiling tiles, the back of drywall, and the inside of walls around leaks among the usual places for hidden mold (EPA).

After a storm: a quick check

• From the ground, look for missing shingles, bent flashing, dented roof vents and granules collecting at gutter downspouts.
• In the attic, with a flashlight, during or right after rain: look for wet or matted insulation, dark streaks on the underside of the decking, and water trails on rafters near vent pipes, chimneys and valleys.
• Inside, check ceilings in closets and bathrooms, which people rarely look up at, and the tops of exterior walls.
• Take dated photos of anything you find. They help with an insurance claim and with the contractor's scope.

Be careful up there. Step only on framing, and wear at least an N-95 if you see growth. CDC advises anyone with asthma, COPD, allergies or a weakened immune system not to do mold cleanup themselves (CDC).

Getting the order right

Storm jobs often involve two or three trades, and the sequence matters:

1. Stop the water. A tarp or temporary patch comes first if the roof can't be replaced right away. In Oklahoma, roofing is a trade the Construction Industries Board regulates, so the roof itself goes to a CIB-registered roofer (CIB).
2. Dry and remove. Wet insulation is usually bagged and removed. Moldy ceiling drywall comes down under containment, following the steps on our mold remediation page.
3. Clean the structure. Decking and rafters with surface growth are cleaned and dried. Badly deteriorated sheathing gets replaced, often as part of the new roof.
4. Close it up last. New insulation and drywall go in only after the roof is tight and the framing is dry.

If the mold is cleaned before the roof is fixed, the next rain starts the process over. If the roof is replaced over moldy decking without anyone looking underneath, the problem gets sealed in.

Attic mold that isn't from a leak

Not every dark attic is a roof problem. Bathroom fans and dryer vents that dump moist air into the attic instead of outside, and attic HVAC units with sweating ducts or an overflowing drain pan, also grow mold on the underside of the decking. Our page on Oklahoma City summer humidity covers the duct and condensate side of that.

Questions people ask

Does homeowners insurance cover mold from a roof leak?

That depends on your policy's wording, and we can't answer it for you. Read the section on mold or fungus, call your agent, and document the storm date and the damage with dated photos before anything is torn out.

Should the roofer or the mold contractor go first?

Stop the water first, even if that's only a tarp. Then remove wet and moldy materials and dry the structure. New insulation and drywall go in last, once the roof is sound.

Can I just spray the attic with a mold killer?

Spraying without fixing the leak or removing wet insulation leaves the moisture in place, and the growth comes back. EPA advises against painting or coating over mold. Clean and dry it first.