Trask Research, Inc. - Mold Problem Solving

Mold Remediation on Drywall

By Matthew Yurina, Mold Inspector/Remediator

CONTAIN- the mold from spreading into uncontaminated areas;

KILL- the mold;

REMOVE- the dead mold and materials used for remediation; and

PROTECT- the cleaned out area against future mold infestations.

Physical mold growth on drywall needs to be remove d c arefully, bagged and disposed of. Standard practice is to cut the moldy material away up to three feet from where the visible growth is. There’s no safe and truly effective way to both kill an d c lean up mold on surfaces like drywall.

The first step in any mold remediation effort is to acquire the proper protective equipment: P100 respirator (to filter mold spores so you don’t breathe them in), gloves, goggles and disposable clothes that cover all of the body. If disposable clothes are not available, then you’ll want to wear clothes that you can wash immediately after the project in the Oxy Mold product. In any enclosed area where you’ll be spraying or fogging, you’ll need a P100 respirator that will also protect against organic vapors.

The second step would be to pinpoint the source of the mold growth an d c ontain the area as close to that source as possible. It may be necessary to erect walls of plastic sheeting to keep mold spores from spreading to uncontaminated areas.

The third step will be to use any method available to you to reduce humidity in the moldy area and dry out all infected surfaces. Oxy Mold MX-501™ will penetrate far deeper into dry surfaces than wet ones. You may need to purchase a dehumidifier to get the humidity below 50%. Air moving devices or fans may be appropriate if you take into account that you could be spreading mold spores around. Containment is recommended, and well as having a HEPA vacuum on hand to limit the amount of spores that get spread around, thus lowering the chances of contaminating new areas.

Effectively killing mold in drywall is virtually impossible. The difficulty isn’t necessarily that the mol d c an’t be killed, but that drywall is too porous, and the safest measure will always be to remove the infected drywall, sometimes even up to three feet in all directions from the actual visible growth.

The quickest, easiest and inevitably the cheapest way to fix the problem will be to remove the drywall (carefully with a box cutter or similar blade that will keep the spread of spores to a minimum), and bag it up securely in Ziploc bags, or 6 mil polyethylene if there’s a large quantity. Once removed from the house the bags can be taken to a landfill.

In most cases there is more mold growth on the inner side of the drywall that cannot be seen, and it could even have contaminated insulation and studs. It depends upon the source of leak or moisture problem that caused the mold, but usually there’s need for performing Mold Tests in order to help understand the full extent of the mol d c ontamination. While condensation due to humidity or improper ventilation may not have caused too extensive of mold growth all the way behind the walls, actual water or sewage leaks could significantly lessen the time it takes for the mold to spread right through the drywall and into other surfaces.

Unless the moisture intrusion and the mold problem have been ongoing and building up for a long period of time, the wood itself should be salvable. Even on the studs you’ll want to remove as much of the mold growth as you can. It may also be necessary to apply the MX-501 once before physical removal of the mold in order to lessen the spread of spores. If you have to cut more than a tenth of and inch into the studs to remove the growth, the studs themselves will have to be replaced.

Once all removable mold growth is safely away from the area, it’s time to apply the MX-501 product twice to the entire infected area, letting the area dry for twenty-four hours in between applications. In areas of small or limited mold infestation it should be satisfactory to apply the MX-501 with a spray bottle or garden pump sprayer, but in any heavy infestation (heavy = you can smell the mold), then a Fogger will be a more appropriate method. The fogger will help to remove this moldy odor. Fogging should only be done in empty or gutted areas.

A cold fogger will atomize the MX-501, turning it into droplets of micron size so that it can penetrate to the deepest roots of the mold and kill surface and airborne mold and mold spores.

When airborne mold spores are involved another step will most likely be needed to actually clean the dead mold spores from the air. You’ll want to look into buying or renting a HEPA grade air mover that can filter the old, contaminated air and remove it from the area while bringing in pure, uncontaminated air. This will be necessary because even dead mold spores can be a health risk.

Once the project is completed it is in your interest to perform post testing (clearance testing). This is the only way to be sure it’s safe to reinstall drywall, insulation, etc. The worst thing you can do is rebuild over an unresolved mold problem. You’ll also want to make sure that the original moisture problem is fixed. Once these tests prove clear, you can re-insulate, rebuild, and repaint.