Trask Research, Inc. - Mold Problem Solving

How to Get Rid of Mold in Your Attic

By: Jim Dobbins, Sr. Mold Remediation Specialist

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.

Mold in the attic is one of the top three mold problems common to a home, affecting 1 in 5 attics in the United States . Left untreated, the health effects can be disastrous.

If you have mold in your attic or suspect it, it is a good idea to do a mold test inside your home for mold. The mold from your attic may have infected your home from small drafts and HVAC systems which blow spores throughout your home.

The only way to be sure is to conduct a laboratory mold test.

Before entering an area that’s infested with mold, you must have personal protective equipment: P100 respirator, gloves, goggles and protective clothing (long sleeves, long pants and hood). Keep skin contact with mold to a minimum.

1.) First fix the problem that caused the mold to form.

Mold in the attic is generally caused by increased humidity and moisture, generally from improper ventilation. The source of the moisture can be from improperly or too few installed attic vents, soffit vents, blocked soffit vents or a roof leak, or any other source of moisture. Generally the moisture builds and forms a dew point in the attic from temperature changes. Over time the moisture is enough to attract mold spores which germinate and form mold in the attic.

A dryer or bathroom may have been vented improperly into the attic or attic vents may either be closed or there may be too few vents to support the moisture in the attic. ALL attics must be vented properly, even during the winter. As moisture builds in the space, mold will form on the rafters, plywood sheathing, and even insulation if sawdust or any other organic material it can use for food is in the insulation. This can lead to mold spores migrating into the home an d c an potentially, if left untreate d c ause a total loss of a home from severe mold infestation.

2.) Get the area as dry as possible before starting your remediation project or it will not be a successful remediation.

Start the process of drying out the space by using at least two fans. One to circulate the air inside the area (more fans may be required for larger areas, and another fan to pump inside air outside of the attic. Some remediators will bring in a HEPA filters or positive air machines during this process to prevent mold spores from moving inside the home and outside of the attic. Some attics will require the use of a dehumidifier to remove excess water from the space, but this is rare as attics are generally the warmest place in the home.

You want the space as dry as possible (below 40-50% relative humidity) before starting the work, so that the EPA registered fungicide Oxy Mold MX-501™ can penetrate deeply into the treatment surfaces and kill the roots of the mold effectively.

- Some attics may need to have moldy insulation removed before the remediation process is started.

- When HVAC systems and ducting are run in the attic, it is possible that the mold may have penetrated into the home. The home and HVAC should be thoroughly tested for mold. You can order a mold test at this link. If there are elevated levels of mold present in the home, it will be necessary to remediate the home as well.

4.) All areas of the attic must be treated with a fungicide to kill the mold

Even if the mold is just in one area of the floor joists, you must treat the entire rafters, plywood sheathing and in some cases other parts of the attic with EPA registered fungicide Oxy Mold MX-501™ with a minimum of two full treatments allowing them to dry in between.

There are two ways to treat the attic. Fogging and pump spraying.

- Fogging is a method of dispersing atomized product into the attic area without having to go through the entire attic and pump spray everything which is a very uncomfortable and tedious task with Personal Protective Equipment ( PPE ) and respirators on.

- If you are fogging break the attic area into quadrants of about 15’ x 15’ quadrants. You will move the fogger to each quadrant, fogging generally 45 minutes per quadrant.

Attic Mold

- If you are fogging it is more convenient to use a cheap 1 hour timer to turn the unit off after it has finished.

- Put the fogger in the middle of the attic (It may be different for different attic layouts) and turn the unit on facing the one of the corner quadrants.

- Simply fill the 1 ½ gallon tank on the unit, turn on the fogger, adjust the unit (if it is adjustable) and set the timer for 45 minutes and leave the area. If you are going to be in the space while the fogger is running, you must wear protective eyewear and a P100 respirator that protects against chemical fumes as well.

- Repeat the process for each quadrant.

- No one should be in or near the crawl space without respiratory equipment while the fogger is running. Do not re-enter the space until the fog has settled for an hour.

- Pump spraying is also a way to accomplish this task, keeping in mind that you must do at least two treatments with EPA registered fungicide Oxy Mold MX-501™ soaking all of the rafters, plywood sheathing in the attic. You should wear a P100 respirator that also protects against chemical fumes while pump spraying in confined areas.

5.) Mold remediators would HEPA VAC any visible mold areas

A HEPA vacuum can be used to vacuum away dead mold spores on your crawlspace. This is not always required in situations of limited mold contamination, but is a good practice.

6.) Mold killers do not remove stains from mold on your rafters and plywood sheathing.

It is possible to kill mold without the mol d c hanging much in color. Molds have VERY strong pigments, and the roots of the mold actually grow into the wood like a water mark. This causes in some cases permanent staining. You may try using bleach to get the stain out prior to using a fungicide. This bleaches the mold but does not effectively kill it. If you are concerned with the stains, you need to decide what type of fungicidal coating to use (white or clear) to either cover the stains or seal them in.

The other option is to "brush" or sand the stains out. This is a tedious task that remediators get huge sums of money to do, but it does remove the stains. Then seal with a fungicidal coating.

7.) Mold prevention is all about controlling moisture and fixing leaks and other moisture problems immediately.

After the mold is dead (from 2 treatments) be sure that there are no improperly installed vents and that the attic is well ventilated. If there are any lingering moisture or ventilation problems, it will be necessary to retreat with Oxy Mold MX-501 every 1-3 months.