Smart Moisture Management
Keys to reducing mold, moisture and mildew
Damage from mold and moisture can range from slight to staggering. Builders who ignore the problem or blame it on sensational journalism should consider these facts:
- The building industry spends $9 billion each year repairing and litigating damages from water and moisture.
- The average builder spends $500 - $1,500 per home in moisture-related callbacks.
- As much as 80% of residential construction defect litigation is due to water and moisture related failures.
- Increasingly, health ailments such as allergies and asthma are being blamed on poor indoor air quality caused by mold.
Moisture problems can be kept in check by having a good understanding of the problem and by paying careful attention during construction.
Why has mold become such an issue?
Moisture problems caused by improper design or inadequate maintenance are more commonly found in old homes, but new construction has been more susceptible to highly publicized, large-scale moisture problems.
The focus on improving energy efficiency resulted in more airtight homes that just didn't breathe like older structures. More complex home designs then created the increased potential for moisture intrusion. Finally, the strong economy created a housing boom, resulting in a shortage of skilled carpenters. These factors worked together to create building envelopes that were more susceptible to moisture damage.
It's important to note, however, that an energy-efficient home is not necessarily susceptible to mold! With proper design and construction, a home can be both energy-efficient and free from moisture-related problems.
What are common sources of moisture problems?
Moisture problems usually stem from two sources - water leaking into the building envelope (bulk water) and moisture inside the home due to excess humidity.
Some of the most common causes of bulk water intrusion are:
- Inadequate or incorrectly installed flashing
- Poor roof design (shallow overhangs, unprotected gable ends, etc.)
- Inadequate grading and poor site drainage
- Incorrect or sloppy installation
Common sources of moisture vapor:
- High indoor humidity exacerbated by inadequate ventilation
- Condensation caused by moist air moving in and out of the building envelope
- Large temperature differences
- Leaking ductwork
How to identify signs of moisture problems.
Too often, homeowners and builders are surprised to find problems caused by moisture intrusion. Look for:
- Peeling paint
- Mold or mildew
Preventing mold and mildew
Here are some key things that should be considered for every home:
- Use roof overhangs and other design features to avoid bulk water intrusion
- Use flashing to divert water away from openings
- Install insulation without gaps, fold or voids
- Use a continuous weather resistive barrier on exterior walls
- Cover crawlspaces to control moisture
- Use exhaust fans to send moist air outside
With good design and attention to proper installation, risks of building and health damage from moisture can be virtually eliminated. Use the following series of segments to learn proper building practices that will help you avoid moisture damage and ultimately mold.