Mold and Moisture
Mobile gets more than five and a half feet of rain in an average year, and the summer air rarely dries out. Mold does not need a hurricane here. A slow drip, a clogged drain line or a damp crawlspace is enough.
Why houses on this coast grow mold, where it hides, how fast it starts after a leak or a flood, and what you can safely clean yourself.
Found mold after a leak?
Stop the water first. Then call {{PHONE}} and tell us how large the area is and where the moisture came from.
Every house in Mobile and Baldwin counties has mold spores in it, and so does the air outside. That part cannot be changed. What decides whether mold grows on a wall is water: a surface that stays wet for a day or two, in a warm room, gives the spores everything they need.
So this page is mostly about moisture. Find the water, dry it fast, keep the house’s own humidity down, and most mold problems never start.
The numbers from the Mobile Regional Airport weather station explain most of it.
The National Centers for Environmental Information publishes thirty year climate normals for Mobile. From 1991 to 2020 the city averaged 67.08 inches of rain a year and 77.5 days a year at or above 90 degrees. July alone averages 22 of those hot days.
Normal yearly rain at Mobile Regional Airport, 1991 to 2020.
Average days a year at or above 90 degrees at the same station.
Normal rain in July, the wettest month of the year in Mobile.
Heat and rain together mean the outdoor air carries a great deal of water for much of the year. When that air finds its way into a cool house, through a leaky duct, an open crawlspace vent or a door left open, it gives up its moisture on the coldest surfaces. That is how a closet on an outside wall, or the back of a dresser against the air conditioned side of a room, can grow mold with no leak at all.
The air conditioner pulls a lot of water out of the air every summer day and sends it down a condensate line. When that line clogs with algae, the pan overflows. The EPA asks homeowners to keep drip pans clean and the drain lines "unobstructed and flowing properly." Many units here sit in the attic, so an overflow soaks insulation and the ceiling below.
An air handler in a hot attic sweats on the outside of its cabinet and ducts. Torn duct insulation or a missing secondary pan can leave a brown ring on the ceiling under the unit long before anyone sees the mold above it.
Some older houses in Mobile sit on piers over a crawlspace, and the median home in Mobile was built around 1975, according to the Census Bureau. Humid air under the floor condenses on cool ducts and joists. A torn vapor barrier or standing water after rain keeps the wood damp for months.
Under sinks, behind the washing machine, at the base of shower walls, and behind baseboards after any spill. Slow leaks do more mold damage than sudden ones because nobody knows to dry them.
Once something is wet, the clock starts. The EPA’s guidance is short.
The EPA says "it is important to dry water damaged areas and items within 24-48 hours to prevent mold growth." That is not long. A ceiling soaked by an overflowing drain pan on Friday night has grown mold on its back by Monday if nobody pulls the wet insulation and dries the drywall.
Indoor humidity matters as much as any single leak. The EPA advises: "If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity." In a Gulf Coast summer that usually means a properly sized air conditioner, a working drain line, and sometimes a dehumidifier. A small humidity gauge from a hardware store will tell you whether the house is staying in range.
The roughly ten square feet rule
The EPA says that if the moldy area is less than about 10 square feet, roughly a 3 foot by 3 foot patch, you can often handle the job yourself. Above that, or if the water was sewage or another contaminated source, or if anyone in the house has health concerns, bring in a professional. Size is only half the question: always find and fix the water first, or the mold comes back.
Water from a river, a bay, a storm surge or a sewer backup is different from a clean pipe leak. It carries bacteria and silt into the walls, and anything porous that it soaked usually has to come out: drywall to above the water line, insulation, carpet and pad. The CDC is direct: "If your home has been flooded and has been closed up for several days, assume your home has mold."
That is especially true after a storm, when power may be out for days and the house sits closed in the heat. If your house took water from outside, read floodwater and sewage in the house before you start tearing out, and see the first hour after water damage for the order of the first steps.
Good mold work is mostly moisture work.
A technician uses a moisture meter and, where it helps, a thermal camera to trace where the water is coming from and how far it has spread. Without this step the rest does not last.
The work area is closed off with plastic and kept under negative air pressure so spores from the cleanup do not drift into clean rooms.
Moldy drywall, insulation, carpet pad and ceiling tile are bagged and taken out. Hard surfaces such as framing are cleaned.
Air movers and dehumidifiers bring the framing back to normal moisture levels, checked with a meter, before anything is closed up.
Readings and photographs go to the adjuster when a covered loss caused the mold, and the walls are put back once the readings say the structure is dry.
Our technicians are IICRC certified, and the same team handles the drying and the rebuild. You can read more about mold clean up and remediation on our branch page.
Do this twice a year, once before summer and once after it.
A small patch on a painted bathroom ceiling usually means the room stays damp after showers. Clean it, run the exhaust fan longer, and check that the fan actually vents outdoors. If it keeps coming back quickly, or the drywall feels soft, look for a leak above.
Usually not. If you can see or smell mold, the job is the same either way: remove it and fix the moisture. Testing can help in specific situations, such as tracing a smell with no visible growth.
Yes. Attic insulation holds water against the drywall, and the attic is hot. Shut the system off until the line is cleared, pull back wet insulation if you can do it safely, and get the ceiling dried inside the 24 to 48 hour window. Photograph it first for your insurer.
A person answers 24 hours a day. Free visual inspection for property owners, and the moisture source is the first thing we look for.