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To The Builders

Indoor Air Quality (IAQ) is an issue that is in the news, and the potential health impact of poor IAQ in new and existing structures is becoming a significant public concern. According to the EPA, over 80% of these IAQ issues are related to mold, and single family residential homes, multi-family and commercial projects are being impacted. These types of structures have been built for many years, and only recently has there been any significant IAQ concern, so it is logical to ask, what has changed?

Experts point to the US Government’s reaction to the 1973 Arab Oil Embargo as the starting point for elevated negative Indoor Air Quality issues. In an attempt to reduce our dependence on fossil fuels and foreign energy sources, the U.S. Department of Energy was created. The new energy standards that the DOE imposed for the Building Industry demanded increases in energy performance through thermal efficiencies of our structures, and the primary focus became one of making buildings tighter and tighter. The result has been construction of highly insulated structures don’t “breathe” as older homes did, and the moisture and VOC’s that are generated inside the structure cannot easily escape. These “real tight” structures are great for energy consumption, but at the price of Indoor Air Quality.

How does all of this relate to mold? Several facts must be considered to answer the question. The facts are:

1. As we lower the Permeability rating on building materials and increase insulation performance, wall cavity humidity and condensation potential increases. According to the DOE, in a residential example, a typical family of four generates roughly fifteen gallons of moisture each day, and in these “tight” structures, that moisture simply cannot escape the structure. So, this moisture often collects in wall cavities.
2. Mold needs three things in order to grow 1) temperature exceeding 40 degrees Fahrenheit 2) relative humidity above 60 per cent for more than 3 days and 3) a food source (wood, paper, plastic, dust, pollen, organic waste, and even other fungi).
3. There are varying amounts of lumberyard mold on lumber when it is delivered to the jobsite, so when the moisture and temperature conditions are right, that mold begins to amplify, or grow.
4. During construction, structures often get wet prior to dry-in, so in many instances, “job site” mold develops on lumber throughout the building, and ultimately, is enclosed in wall cavities.

All these facts point to a very high probability of developing mold growth in unprotected, sealed wall cavities and sub floor structures (crawlspace).

As a Builder, why should you be concerned?

• Consumer Awareness. Home Owners are increasingly concerned with mold and Indoor Air quality issues, and realtors are becoming more aware of the issue and their personal liability in mold situations.
• Litigation - Mold related complaints and litigation have become significant liability factors for Home Builders, and as awareness grows in the consumers mind, that liability will only increase.
• Potential Costs – Liability insurance costs and post-construction mold remediation costs are increasing every year.
• Financial Institution concerns – Banks are becoming more aware of the issue and their liability/risk, and some are beginning to require a mold mitigation strategy from builders as a construction loan condition.