Heritage Restoration, Inc.

Mold Issues #2

In the last column I responded to a reader, Kit, who wrote in asking how to treat mold on the exterior of her house. Yet there was the potential of the problem being more than the exterior, so I decided to call Kit. While treating the mold can be somewhat straight forward, determining the cause is necessary to insure the building is healthy and the mold does not come back. Here is what I found out:
• The problem got worse over the past 3 years.
• The house has shingle siding.
• The house is sited on 1 acre of woods, mostly pines. There is only one spot with trees about 2 feet from the house, with the canopy overhanging a bit.
• There is a pond a few hundred yards away.
• Insulation was blown into the walls a few years ago.
• Central air was put in about 3 years ago. It smells for about a week after the air conditioning turns on for the season.
• The mold is the worst above the outside HVAC condensers.
• The house was built in 1975.

Mold is everywhere, yet some areas are more than others. According to the Environmental Protection Agency, “There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.” Moisture control, or even awareness, seems to be the single most overlooked and/or under considered consequence of building construction or retrofit. Water and moisture are the reasons most of our clients contact us. Water and moisture can make a house an irritant, uninhabitable, cost thousands in repairs, or worse, destroy it. The concentration of mold and its effects are dependant on the occupant.

The EPA further states “One third to one half of all structures have damp conditions that may encourage development of pollutants such as molds and bacteria, which can cause allergic reactions — including asthma — and spread infectious diseases.” That is a staggering number, although I believe it. Many people don’t know their house or place of work is creating heath problems. It can be as little as a smell, a runny nose, coughs, exhaustion, or even more debilitating health concerns. If you are suffering from any of these conditions, and you think it is your building, get a building diagnostic completed.

If you are having the beginning stages of mold growth on the surface of the building, like Kit, then the time for a diagnostic is right now, before it becomes a bigger problem. Some of the methods of diagnosis are:
• Infrared camera. An infrared camera can detect moisture in walls. If moisture is present, especially in the winter, then it will read colder than the rest of the wall.
• Moisture Meter. A moisture meter probe inserted into the wall cavities can provide an accurate reading of how much moisture is present.
• Relative humidity meter. There are good digital indoor Digital Hygrometers that can cost about $45 and up. You want to be sure your building stays within 30 and 50% relative humidity. Any higher and the moisture will condense in walls, or seep through walls and create mold on the exterior.
• Look for active mold spores on walls, ceilings, attics and basements.

After you assess the building, you want to mitigate the problem. This is where it gets complicated. You could reduce moisture by exhausting it at its creation, reducing the amount in the air, and preventing it from settling inside you walls or closed in areas.

The blown in insulation may be part of the problem. If the walls are not well air sealed, and the insulation was loose blown-in, not dense pack, then the insulation can be acting as a sponge. If the general area is damp and the walls are leaking air, there is a challenge in keeping the walls and insulation dry. Air sealing will help, as well as reducing the amount of interior moisture by a properly sized dehumidification system, getting to the 30-60% relative humidity.

Here are some quick list suggestions:
• Install bathroom and kitchen vents that are connected to the outside.
• Air-seal the house.
• Install a dehumidification system big enough for the house.
• Clean any ductwork annually. There are also in-line hydroxyl generator machines that will eliminate the presence of mold and other irritants.
• Clean gutters and make sure downspouts are directed away from the house.
• Cap any dirt basement or crawlspace floors with 6-mil plastic or concrete.
• Clear trees or canopies that are closer than 10 feet from the house.

The long and short of it is cleaning the mold will keep it away for a bit, but fixing the source of the problems is what keeps it away for good.

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