Mold Awareness Month: The Five “D’s” to Controlling Mold

Lucas Hamilton

The U.S. Environmental Protection Agency (EPA) estimates that 50 percent of schools nationwide have issues linked to poor indoor air quality.  In many cases, this condition is linked to mold growth in buildings. Mold poses a serious health risk to individuals with respiratory health issues.

This has been a summer of record high temperatures and humidity across the country. This is a perfect storm for the propagation of mold.  As I discussed last year, mold is like a four legged stool.  Mold needs four things in order to grow:  food, water, oxygen and temperature between 41 and 104 degrees.  It is almost impossible to eliminate the potential for molds and mold spores to infiltrate an environment unless you control the elements that give mold it’s ‘legs.’

Controlling the moisture in and around a building is one of the best methods for maintaining a mold-free environment.  By following the five “D’s” you can protect against any opportunity for mold growth or infiltration:

De – Leak – Check for leaky roofs, walls, windows, foundations, facets and pipes regularly and repair them as soon as possible.

De – Bubble – Moisture trapped behind wallpaper paired with wallpaper glue is a perfect recipe for potential mold growth.

Dehumidify – Use dehumidifiers and air conditioners, especially in hot, humid climates to reduce moisture in the air.  Exhaust fans should be used in bathrooms and kitchens to remove moisture to the outside.

Dry – Clean and dry any damp furnishings within 24 to 48 hours to prevent mold growth.

De – Odor – Keep in mind, if you have had a leak, the first sign of mold may be musty or moldy odors. But do not sniff or touch mold.  If you suspect mold, contact a certified mold inspector.

Mold has a long history and a survival instinct that is almost unmatched in nature.  But let’s keep mold outside by making sure that moisture is managed in our buildings.

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

Mold Awareness Month: A Historical Perspective on Mold

Lucas Hamilton

Lucas Hamilton

As we come to the close of Mold Awareness Month, I thought I would offer some perspectives on the history of mold as a follow-up to my earlier blog “Mold is Like a Four-Legged Stool.”

Mold has a long and colorful history. It is a living and very dynamic organism.  Mold spores are everywhere; on clothing, items you buy in the store, in walls and buildings.  It can exist in pores within materials not visible to the eye but once that material is exposed to a temperature of 41° – 104°, has moisture, oxygen and food, it will grow.

Historical References to Mold

  • One of the first references to mold remediation occurs in the Bible in the book of Leviticus chapters 13 and 14 in which God not only reveals that he placed mildew in a home, but offers specific directions about how to remediate the mold using the blood of a dead bird.
  • The Curse of King Tut’s Tomb was Aspergillus mold the most common genus of fungi with 160 species.  In 1922 archaeologist Howard Carter and his team discovered King Tut’s Tomb. Shortly after attending the opening of the tomb in 1922, Lord Carnarvon, as British sponsor of the expedition, died.  It was speculated that supernatural forces were at work. Within five years, 11 of the people who had entered the tomb with Carter were also dead. 
  • The Salem Witch Trials – It has been discovered that Claviceps purpurea a fungus that grows on rye wheat which was used to make bread can cause Ergotism, a disease which affects the pores and can cause hallucinations and convulsions.  In testing artifacts from that time period and exhuming the bodies of those thought to be witches, the bacteria was found.
  • The Irish Potato Famine was caused by Phytophthora infestans, a water mold that attacked the potato crop in Ireland between 1845 -1849 causing thousands to starve and others to flee the country.

Of course there are beneficial uses for mold.  Molds help to breakdown organic matter. Some of my favorite cheeses are ripened using molds. Antibiotics, such as Penicillin are created from molds.

But perception is always in the eye of the beholder.  If you think your neighbor is possessed or if you suffer from headaches, redness and skin irritation, sneezing, watery eyes or more seriously, vomiting, diarrhea, or constant fatigue, it could be from exposure to mold. While it seems mold can cause many symptoms one must remember that there are thousands of species of mold and different species can produce different reactions within different people.

I have come to view human beings as Portable Organic Detection Systems (PODS). We have genetically learned what things are bad for us. Things that smell bad we generally assume are bad for us. It is a learned response that is grounded in a perception as well. If you suspect you may have mold in your walls, get on your hands and knees and sniff at the wall outlets. If there is mold in the walls, in many cases you will smell it there.

Mold has been around for thousands of years and will probably be around for thousands more. Mold is nothing to be afraid of, but it is something we need to control for our health and well being as well as the health of our buildings.

Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation. 

Mold Awareness Month – Mold is like a Four Legged Stool

Lucas Hamilton

Lucas Hamilton

Since there is a “month” for just about everything else, why not "mold awareness?"  While some may think this is a non-issue, I assure you, it is not.  Last year the governors of several major states proclaimed September of 2008 to be Indoor Mold Awareness Month.  Other states have now joined the push to raise public awareness of this potential health issue.  For people who have been exposed to mold and have had an allergic reaction, because that is what it is in most cases, it can be a serious problem. Reactions such as a rash, itchy skin, difficulty breathing or headaches have been a result of inhaling mold spores. Over the past 20 years, mold has become very well understood in buildings because of litigation, which bolstered research and conversation regarding the cause, effect and damages that result from mold.

Mold needs four things to live:  a temperature of 41 to 104 degrees; sufficient moisture content; oxygen and food. Mold is like a four legged stool, if you knock one leg out the stool falls over. If mold does occur in buildings there are very well established guidelines for remediation. Mold does not consume building materials, it does not cause structural issues – fungus does – which occurs at a higher moisture content than mold.  Mold is more common and can be dried out, killed, and wiped away.  If you keep the area dry from that point on, you will not have further problems.  People develop issues with mold when it becomes active and releases spores into the air.  Those spores are inhaled and, like ragweed, can cause an allergic reaction.  The trick is to control the elements of the four-legged stool. But how do we control these elements?

Temperature is something we create. We know that mold’s sweet spot is 41 to 104 degrees and I guarantee that you can find that temperature range in just about any wall anywhere in any season. 

Oxygen – you’re not going to get rid of oxygen unless you build your building on the moon. 

Food – starch or sugar typically are the food sources for mold. You can try to build a building that is food free but I guarantee you food will show up. A perfect example of how a food free environment doesn’t last is your shower, which is generally ceramic, glazed tile, glass, chrome, vinyl – there are no starches or sugars in these materials – but mold will grow because food shows up in things like soap.   Starch is one of the binders for soap. That’s the problem with trying to develop buildings without food sources, because food will show up in the form of contamination through the use and occupancy of the building.

The accepted strategy among building designers and construction professionals is to control the moisture so that you do not have a17% wood moisture content in materials. This is the moisture content at which mold will appear.  

We’ve never really been able to completely keep moisture out of our building constructions. The trick is to build living, breathing, drying assemblies that keep moisture content levels low. You can live with bursts above the 17% as long as you get the water out before the mold begins to propagate. If mold does occur in your building, deal with it in a considerate and rational approach: Protect people from exposure to the airborne spores, clean it up, dry out the substrate, and prevent the surface from achieving elevated moisture contents in the future.

 Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation.  

                                   Nolan Mug shot             

Nolan Day, Architectural Systems Manager at CertainTeed Corporation contributed to this blog.