I have just discovered that I have black mold growing in my unfinished attic. I have been told it is caused by poor ventilation. How and where can I have the mold tested? Should I try to remove it? How do I find someone to remove the mold properly ?- Caroline, Illinois.

Mold can commonly be found growing in attics. Attic mold growths can have a variety of causes. Inadequate ventilation is one of the major contributing factors ( particularly to very extensive infestations). In northern climates warm moist air from people and their activities rises up toward and through the ceiling (around light fixtures, trap doors etc.) where if the attic is well ventilated it passes to the outside. If the attic is poorly ventilated the moisture will condense on cool/cold surfaces where it can serve as a focus for mold growth. When the temperature is very cold you may even have icicles growing in your attic!

Attic ventilation requirements are usually specified in local building codes. Newer houses typically are ventilated by a combination of soffitt and ridgeline vents. In other cases individual vents are installed in the roof itself. Attics that are particularly prone to moisture problems may need to be ventilated with vents that have motorized fans. In older houses vents were located on the two sidewalls near the peaks of the roof. In most cases such ventilation was and continues to be adequate. It may mot be adequate if the building is located on a wet site.

The degree of mold infestation in attics subject to poor ventilation and condensation varies considerably. In minor infestations mold can be seen growing on roof rafters very close to sites where moist air is passing through the ceiling. In the worst case heavy mold infestations may be seen on most roof rafters and if tested on attic insulation (particularly if it is cellulose).

Generally speaking mold infestations in an attic poses a small risk of exposure to individuals in spaces below. This is due to the fact that air in most cases flows upward and outward. Downward flow occurs only occasionally and depends mostly on outside weather conditions as well as factors which cause overly negative pressure conditions to occur in ones house. These include the use of fireplaces, continuous bathroom exhaust, etc.

If the attic has light to moderate mold infestation it may be sufficient to install attic ventilation (which will dry out the attic reducing future mold growth). You may mot have to do more than this.

Black mold in your attic may be a variety of things. In most cases black mold on your roof rafters is not likely to contain Stachybotrys the toxic mold we have heard so much about. Wet cellulose (such as attic insulation) on the other hand has a high probability of being infested with Stachybotrys.

As indicated above you may choose not to remove mold in your attic if the infestation is light. If it is heavy or you simply want to remove it to feel safer, it would be prudent to have it tested first. I recommend the use of transparent sticky tape to take samples. Mold types can be identified by local laboratories that provide microbiological testing services (see your yellow pages) or by national laboratories such as Aerotech (aerotechlabs.com) and Air Quality Sciences (www.aqs.com). Talk with laboratory personnel on the proper way to collect samples.

To my knowledge there are no companies that specialize in mold re-mediation. There are however, companies that specialize in post fire and flood re-mediations. Such companies can do mold re-mediation as well. However, they must be instructed on how to conduct the re-mediation to minimize contamination of your home, particularly if toxigenic mold species such as Stachybotrys is present. See other articles on this web site which discuss mold re-mediations.