A home owner in Tampa recently asked me why he cannot just paint over our cut out and throw away a 2X2 foot spot of mold growing on he ceiling in the laundry room. The mold was caused by an overflow from his A/C condensation pan under the air handler in the attic space.
The answer has several parts but first taking action to prevent a reoccurrence is paramount. The A/C drain pan probably overflowed because the drain line was clogged or obstructed. The A/C condensate pan is like a culture dish in your attic. Mold spores are present in the air almost all the time. All they need to grow is water and a food material. The A/C condensate pan is wet most of the time. Any biological material that falls into the pan will supply the food and grow a slime mold. This slime mold clumps up and blocks the drain line and when enough water backs up into the pan it overflows onto the insulation below and eventually onto the back of your drywall which is your ceiling below. There are two important actions you can take to prevent future overflows and subsequent water and mold damage.
1. Ask your A/C service technician to put an antimicrobial tablet into the A/C condensate drain pan. This tablet will discourage mold growth and help to keep the drain line clear.
2. Attach a wet/dry vacuum to the drain line outside your home where it drains onto the ground. It is a PVC pipe with a “P” trap bend on the end. Do this quarterly and you will most likely never have a blockage again.
First: Why can’t I paint the mold spot with kilz paint and just cover it over? Kilz does not kill,it just covers. The mold will continue to grow in and on the back of the drywall, on the studs or roof trusses and on the plywood decking in the attic space and on the paper backing of the insulation. Applying a sealer to drywall will also slow the drying process and the mold will stay viable longer. Any further wetting or high humidity will jump start the mold growth and it will spread to adjacent building materials.
Second: The affected drywall must be cut out bagged and thrown away. Not just the visible growth but 2 feet beyond the visible. The wet insulation in the attic should be thrown away. The drywall should be cut inside containment with negative pressure. In plain language, a sheet of 6 mil poly is set up to isolate the growth area from the rest of the home space. Ideally, an air scrubber, a unit that filters the air through a HEPA filter, is attached to the containment. This draws a negative pressure inside the containment and does not allow air from inside to escape. The drywall is carefully cut with a utility knife followed by a hand held HEPA vacuum to prevent mold spore from becoming airborne. Any affected materials, drywall and insulation, must be bagged inside containment and thrown away outside the home.
Mold spores are infinitely small, as small as .05 microns, and very aerodynamic. This is why containment and HEPA vacuuming and filtration are needed. A HEPA vacuum will capture particles as small as .03 microns. Mold spores from affected dry wall that become airborne will be carried throughout your home by air flow or through you’re A/C system and if they land on a wet surface with a food source will begin to grow.
Third: The structural materials behind your drywall may also be affected with mold growth. Mold will grow on any wood or paper product. If studs or rafters are affected they must be sanded down to clean wood and encapsulated with an antimicrobial sealer. This process should also be done in containment with negative pressure and HEPA filtration.
Finally: The affected areas should be treated with antimicrobial before the drywall is replaced. This includes any surfaces in the attic space that might have been wet with the slime mold water. If you want a record of the mold remediation process which states that the indoor air is free of mold spores, from an indoor source at the time of remediation, an air test“clearance” should be performed before the reconstruction. This is very beneficial if and when you sell your home in the future. The future buyer will have documentation from a third party CIE (Certified Indoor Environmentalist)that the mold issue was corrected following IICRC, Institute of Inspection,Cleaning and Restoration guidelines.
The smart home or condo owner hires a Professional Water Damage Restoration and Mold Remediation Company that follows the IICRC guidelines, who has their restoration work certified by a CIE and is certified by The Indoor Air Quality Association as a leader in the field of Water damage restoration and Mold remediation.
Mold growth in the living area of your home is one of those things best left to the professional. Mold growth that is not remediated properly may affect you and your family’s health and the value of your home.
Follow these practices to prevent mold growth in your home:
• If you have a flood or water damage be sure to dry the wet materials quickly and completely. Hire the best local Water Damage Restoration Contractor.
• Keep the humidity in your living space below 55%. Mold will not grow without sufficient moisture. Use your A/C system and additional dehumidification if needed.
• When you go away for more than two days set your thermostat at 78 degrees and if you have a humidistat set it at 50. Your Thermostat and humidistat are typically out of calibration by up to 8 degrees.