Drying out as Fast as Possible
Keep windows and doors closed, seal air leaks and duct leaks as much as you can (since outdoor air is humid), and remove moisture sources (houseplants, water in toilets, etc.). Cover drains to block sewer gas from entering home. Trim landscaping away from walls, eliminate sprinklers, and expose at least 6 inches of slab or foundation under siding.
Run the air conditioner (A/C) at about 72 degrees, auto fan setting (to avoid returning condensed moisture back into the air); do not overcool since that can backfire by raising RH and making materials cold enough to cause condensation; change return air filters often.
Get and run dehumidifiers on low RH setting, with a hose to discharge into a drain or outside; locate near fans to help distribute dry air; check and change filters often.
If you can’t get dehumidifiers, run electric space heaters at the same time as A/C; the heat will lower RH, keep materials warm, and make the A/C run longer to increase dehumidification.
Run ceiling fans and portable fans to blow low RH air across damp materials.
Get a digital hygrometer to monitor the indoor RH; keeping air below 50% RH will allow drying, but 30-40% is even better until all is dry.
Monitor RH with just A/C for a few days, if possible, to see if RH stays below 60% without the dehumidifiers or heaters. If not, run them longer.
Mitigating Mold Damage
Mold can develop within 24 to 48 hours of a flood so remove wet contents, including carpeting and bedding, as soon as possible. If an item has been wet for less than 48 hours, it may be salvageable. Notify your insurance company before removing items to ensure that you’re not affecting coverage. Always photograph the flood-soaked items. Drywall with mold showing on the surface should be cut out and removed. Remove a minimum of 12” around the visibly moldy area and a minumum of 12” above all drywall and insulation that is wet from flood water. You can remove insulation from behind drywall an additional 12”, but don’t pull out more than that or it will be difficult to replace without removing more drywall.
If you are removing drywall it’s generally better in the long run to remove right up to 4’ from the bottom, because that will save time when reinstalling since you can use full sheets and drywall is relatively inexpensive. If you already have a contractor, you can verify with them how much you should remove.
Mold growth can be controlled on non-porous surfaces by cleaning with a non-ammonia detergent or pine oil cleaner and disinfecting with a 10% bleach solution. (Caution: Never mix ammonia and bleach products, as the resulting fumes can be highly toxic.) You can also use a mixture of 7 parts alcohol to 1 part water. Always test this solution on a small area of the item or area you’re cleaning to be sure it doesn’t cause staining or fading.
Bleach is quite corrosive so should never be used on metals or near the air conditioning system and it poses a variety hazards to people (burns, asthma trigger, etc.). It also has no residual effect, so does not prevent new growths of mold or bacteria if conditions remain damp. Bleach should never be mixed with ammonia or an acid (like vinegar) since that can create toxic gas.
You can also use concrobium in lieu of the bleach solution. Concrobium kills mold by dehydration and it also leaves a “residue” behind that will prevent any mold spores from reproducing again and causing another issue. It’s a “green” product that isn’t harmful to people or pets, and it doesn’t have the harsh odor that you’d get from spraying bleach. It’s available at HomeDepot and Lowe’s in gallon sizes and you just put it in a spray bottle or in a yard sprayer and soak the area down. In order to work as effectively as it can, you need to spray enough to let the area stay wet for a minimum of 10 minutes. Also, with Concrobium you DO NOT dilute it at all, you use it straight from the bottle.
Do not apply anything that would impede drying to the indoors. If you want to use a fungicide (to kill mold) or fungistatic (to prevent new growth) coating, make sure it’s very water vapor permeable (prefer perm rating of 5 or higher).
Always wear rubber gloves and an N-95 or higher mask or respirator when cleaning flood-damaged items. More details here.
Textiles and Furniture
Rugs may be dried and then cleaned professionally, which could cost $100 to $500 or more, depending on the size and number. Large pieces of furniture that are saturated will likely be difficult to dry effectively, and should typically be discarded, though you can remove any cushions or upholstery and dry the base of the furniture out with fans.
With wood furniture, first get it to some place dry. Remove drawers from case pieces and take any wet clothing or textiles out of them. Remove metal knobs, dry them and put them in labeled resealable bags so they don’t get lost. If left on wet wood, they can corrode and leave stains.
If drawers are so swollen that they don’t pull out easily, try removing panels on the back to take wet things out of them. Otherwise, you might damage drawers trying to force them out.
Should I have my home tested for mold?
Generally speaking, hiring a professional to test your home for mold is an unnecessary expense at a time when expenses are already piling up. In most cases, you can detect mold simply by using your own eyes and nose, being aware of:
Discoloration of any sort on your walls or ceilings
Textured growth of any color (most commonly black or green)
Musty or earthy smells
Worsening of symptoms that might suggest an allergic reaction, such as stuffy nose, watery or irritated eyes, and wheezing.
Hiring a mold assessor is a good idea after you’ve cleaned up and before you cover up your walls again, just to be sure you didn’t miss anything.
Paper, Records, and Books
Valuable papers such as books, photographs, and stamp collections can be restored with a great deal of effort. They can be rinsed and frozen (in a frost-free freezer or commercial meat locker) until you have time to work on them.
A slightly less effective alternative to preserving an item is to place items in a sealed container, such as a plastic bag, with moth crystals. Papers should be dried quickly when they are thawed or unsealed (a blow dryer will do). Don’t try to force paper products apart, just keep drying them. Photocopy valuable papers and records soon because substances in the water may make them deteriorate.
Rinse books with covers closed. Insert wax paper between leather, cloth or paper materials that are tacky or sticky. After rinsing, pack them spine side down in a single layer in sturdy containers. (Stack, but do not crush the books.) Then place the container in a freezer with a frost-free setting on the lowest possible temperature. This drying process can take weeks or months.
If a computer disk or tape has valuable information, rinse it in clear water and put it in a plastic bag in the refrigerator. Later, you can take it to a professional drying center and have the data transferred to a good disk or tape.
Many companies that specialize in restoring computers and computer records after a disaster are members of the Disaster Recovery Institute. To find a member company near you, you can all the Institute at (314) 846-2007.
Hardwoods have a decent chance of surviving a flood, but composite floors are likely ruined and will need to be replaced.
Follow these steps to dry out wood floors:
Remove all water from the area.
Open windows if possible to improve air flow.
Clean off dirt and silt.Use fans and open windows to dry out the floors.
You can touch wood flooring to see if it is still wet.
Replace any boards that are beyond repair, if necessary, and refinish the entire floor.
Before You Close Up Walls
You can speed up the drying process by using your AC and humidifiers and fans effectively. 17% moisture is FEMA standard for Houston. Sometimes after several days of dehumidifiers and fans, the moisture level can still be as high as 50%. You need a moisture meter to be sure that you’re at or below 17%. You can get moisture meters at hardware stores or online for as little as $20, and they’re better than guessing.
Next Step: Working with Contractors