Gainesville air, by NOAA's count
NOAA keeps an engineering weather station in Gainesville, and two parts of its record are worth knowing before you deal with mold.
The first is wet-bulb hours. In an average year at Gainesville, NOAA counts about 2,137 hours with the wet-bulb temperature above 73°F and about 4,252 hours above 67°F. Wet-bulb temperature reflects the water vapor in the air as well as its heat, which is why people who size cooling and dehumidifying equipment pay attention to it.
The second is the design temperatures. NOAA's engineering weather data for Gainesville, at an elevation of 151 feet, gives a 1% summer design temperature of 92°F with a mean coincident wet-bulb temperature of 77°F, and a 99% winter design temperature of 33°F. An HVAC designer plans a system around conditions like these.
The cooling system is the dehumidifier
Mold needs spores, food and water. Spores are in every house. Food is anything organic: the paper face on drywall, wood trim, carpet backing, cardboard boxes, dust. Water is the part you can actually manage, and in most homes the air conditioner does most of that managing by pulling moisture out of the indoor air as it cools.
That is why so many mold problems trace back to the cooling system in one way or another:
- A unit that short-cycles. Equipment that brings the rooms down to the setpoint in a few minutes and shuts off may not run long enough to dry the air.
- A blocked condensate drain. The line can clog, back up into the pan and spill into a closet floor or the ceiling under an attic air handler.
- Sweating ducts and registers. Cold supply air running through a hot attic can condense on duct jackets and drip onto insulation and drywall. Registers can drip into the room.
- A house shut down. Turning the system off while you travel lets indoor humidity climb, and mold can appear on closet walls, upholstery and stored items.
Ask an HVAC technician to look at sizing, run time, the drain and the ductwork whenever mold shows up near vents, closets or ceilings.
Other places water hides
- under kitchen and bathroom sinks, and behind the dishwasher and refrigerator;
- at toilet bases and around the water heater;
- at window corners and sliding doors where seals or caulk have worn;
- along roof flashing and around vent pipes;
- in bathrooms and laundry rooms whose exhaust fan is missing, too small or vented into the attic.
Fix the water before the mold
Scrubbing or spraying growth that sits on a damp surface only buys time. The order that holds up is: find the source, stop it with the right trade, dry the structure and prove it is dry with moisture readings, then remove or clean what grew. A company that wants to start cutting drywall before anyone can name the cause is skipping the step that decides whether the work lasts.
Florida's rules for mold work
Florida's statutes set out two points that matter when you hire. The Florida Department of Business and Professional Regulation licenses mold remediators who pass the licensing exam and have documented training in water, mold and respiratory protection. A mold remediator may not perform a mold assessment on a structure its company remediated within the previous 12 months, and a mold assessor may not remediate a structure it assessed in that period, with an exception for certain Division I contractors.
What to do with that:
- Ask each company whether it is acting as the assessor or the remediator on your house.
- Look each company up with DBPR before you sign, and make sure the license it shows fits the role it is taking.
While you are thinking about indoor air
Radon is a separate issue from mold, with a separate fix, but it is worth a test while you have people looking at your house. Florida Department of Health data indicate that 1 in 5 Florida residences has radon above the EPA action level, and elevated levels have been found in all types of Florida buildings, including manufactured homes and high-rise condominiums. The department offers free test kits.
Signs that call for a closer look
- a musty odor that returns after cleaning;
- dark or greenish spotting on ceilings near supply vents, in closets or around windows;
- paint that blisters or peels, or drywall that feels soft;
- baseboards that swell or separate from the wall;
- a ceiling stain under the air handler;
- water beading on registers or window glass.
None of these tells you how far growth has spread behind a surface. Each is a reason to find the moisture and have the area opened and checked.
Looking safely
If you pull back carpet or remove a panel to look, wear gloves, eye protection and a well-fitting disposable respirator. Keep children and pets out of the room, and don't dry-brush the growth or point a fan at it, which can carry spores into other rooms. Talk to your doctor about any health concerns.
Questions for a remediation company
- What caused the moisture, and who will fix it before cleanup starts?
- Who did the assessment, and is that a separate company from yours?
- How will the work area be sealed, and will you run filtered negative air?
- Which materials come out, and which can be cleaned and kept?
- What moisture readings will show the framing is dry before walls are closed?
- Can I see proof of liability coverage and workers' compensation?
- What goes in the final report?
Before work begins
Get a written scope that lists rooms, materials, containment, drying targets and how completion will be shown, and compare every quote against that same scope. If you expect to file a claim, call your insurer early, read the mold terms in your policy, and keep photos, reports and invoices in one place.