Stachybotrys = Black Mold

Mold in attics

It happens to countless homeowners around the end of the year – you make the annual visit to your attic to collect the holiday decorations and what do you find? Spots and blotches covering the bottom of the roof sheathing. Worse yet – it turns out to be attic mold!

Although mold growth in attics is generally black it most likely is not “black mold”

What is most commonly referred to as “black mold” is Stachybotrys chartarum.

Stachybotrys growth is caused by moisture from water damage, excessive humidity, water leaks, water infiltration, or flooding.  Most attic mold problems are not the result of actual water intrusion.

Stachybotrys growth occurs on material with a high cellulose and low nitrogen content, such as fiberboard, gypsum board, paper, cardboard, etc. The surfaces generally affected in attics are roof decking and framing. These are not the common food sources for this type of growth.

Typical causes of mold growth in attics :

Improperly installed insulation Insulation can block soffit ventilation preventing the necessary airflow or cross ventilation from vented soffits.

Inadequate roof or soffit ventilation Not having enough soffit or roof vents will also restrict airflow again causing favorable conditions for mold growth.

Improper bathroom fan ventilation Bathroom vent fans improperly vented or vented directly into the attic space causes humidity.

Inadequate insulation Lack of insulation can result in a temperature difference causing condensation on the roof decking.

Ice dams

These are often caused by warm air seeping into the attic which causes the snow and ice on the roof to melt. The water drains to the edge of the roof (which is colder than the rest of the roof because it is an overhang and not warmed by the attic), freezes and creates an ice dam. As this process is repeated daily, the ice dam grows larger. Eventually water is forced under a shingle where it can seep into the house and or cause water staining and growth on framing and roof sheathing .

Bleach as a mold killer?

Chlorine bleach is well known for killing bacteria, and it has no rivals when it comes to removing color.  But is bleach effective in killing mold?  Not really. Here’s why:

  1. It is too diluted and thus too weak to permanently kill mold unless the mold is simply sitting on top of a hard surface like a counter top or sink.
  2. What little killing power chlorine bleach does have is diminished significantly as the bleach sits in warehouses and on grocery store shelves or inside your home or business [50% loss in killing power in just the first 90 days inside a never opened jug or container] Chlorine ions constantly escapes through the plastic walls of its containers.
  3. Chlorine bleach’s ion structure also prevents chlorine from penetrating into porous materials such as dry wall and wood— It just stays on the outside surface, whereas mold has protected enzyme roots growing inside the porous construction materials. When you spray porous surface molds with bleach, the water in the water solution soaks into the wood while the bleach chemical sits atop the surface, gasses off, and thus only partially kills the surface layer of mold while the water penetration of the building materials fosters further mold growth.
  4. Chlorine Bleach is not registered with the EPA as a disinfectant to kill mold. You can verify that important fact yourself when you are unable to find an EPA registration number for killing mold on the label of any brand of chlorine bleach.

Distressed property

We all know that mold contamination negatively affects indoor air quality. In other words, when a building has a really bad odor, mold is often to blame, at least in part.  But there can be a whole host of other reasons for bad odors, and they can be pretty nasty.

Imagine a house where the garbage has piled up for months, cats or other pets run wild, and the house is infested with rodents and insects.  Get the picture?

This is what we call “distressed property”.  The house is full of e-coli and other bacteria and pathogens. Sure, there’s plenty of mold throughout the house, but that may be the least of the problems. Sadly, sometimes we find elderly people living in these squalid conditions.

In cases like these everything has to go, and it’s a dirty, difficult job.  The garbage and trash has to be removed and disposed of, along with animal waste and contaminated materials.  Then the cleaning begins.

The process of cleaning a distressed property is not unlike our standard protocols for mold remediation.  Usually there is a lot more damage to the structure, though. Hardwood floors that have been saturated with cat urine, for example, is hard to save. If you are thinking of purchasing a property with these conditions get an estimate from a remediation contractor for “cleaning” the cost and exposure saved over DIY cleaning is usually well worth it.

Michigan Mold – Top 3

  1.  Poor ventilation in the attic.  Often mold in the attic isn’t found until the house hits the market and a home inspector pokes his (or her) head up there and sees the black spots or white fuzz.  This is usually results of poor ventilation, and can be compounded by inadequate insulation or a bathroom ceiling fan vented into the attic.
  2.  Damp and wet basements.  We all love to finish our basements, don’t we? Even if we live in areas with high water tables. So, what happens?  The basement gets damp and stays damp.  And that includes wood joists, carpeting, and wall board, all excellent food sources for mold.
  3.  Do-It-Yourself water damage clean-up.  If you have the unfortunate luck of experiencing water damage from a pipe burst, hot water tank break, washing machine hose pop out or any other source of emergency water damage, call an expert in water removal and drying. They will be able to find moisture hidden behind walls and under flooring, and they will use professional equipment to dry the area properly and thoroughly. If you try to do it yourself with a wet vacuum, you will almost certainly leave some moisture behind.  And that’s where you’ll find mold later.  As you may know, insurance coverage for mold is very limited, so don’t take that chance.

Do you have a question about mold?  Get straight answers from an expert.

air experts of Michigan

Majeske Home Inspection Services

Hernick Environmental LLC - 
Frankenmuth, Michigan

air experts of Michigan

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