Humidity / Indoor Air Quality Problems

We were recently contacted about a 5,000SF house in Muncie, Indiana that was less than two years old and had been experiencing severe humidity problems and "sweating" on certain windows in the home.  Some rooms were warmer or colder than others, mold had begun forming around base trim, and the family's young son had developed asthma as a result.

After talking with the homeowner about these issues we learned that there had been a downspout and drainage problem that had been allowing rainwater to enter into the walk-out basement area of the home and had caused some minor water damage.

The drain lines from the downspouts in the front of the home had also been crushed during the initial construction and we not allowing proper drainage away from the house. The problem in the back basement of the home had since been corrected, but the front corner of the house was still experiencing excessive humidity and temperature problems.

We began our inspection by doing a visual check of the inside and outside of the home, looking specifically at the orientation of the building in respect to the sun's path, where downspouts emptied near the building, how the heating and cooling system is distributed throughout the house, the size of the furnace, and how the basement and crawlspace areas are laid out.

While we conducted the visual inspection, we also used a Flir infrared camera to view any temperature differences in the exterior surfaces of the house.  Using an infrared imager allows us to discover areas of potential air leakage, insufficient and/or missing insulation, and moisture that may be hidden behind the drywall or trim and invisible to the naked eye.

After the initial visual and infrared inspection we added another diagnostic tool called a blower-door to help us diagnose the source of the problems.  A blower-door is used to create a strong negative pressure difference within the house, which simulates 20 mph winds hitting the house from all sides simultaneously.  When used in conjunction with an infrared camera, these two tests provide a very powerful tool to easily locate points of air leakage, moisture, and missing or inadequate insulation by amplifying the temperature differences in those areas. 

What we found was that all of the windows and doors were, in fact, air-tight and insulated properly, and the insulation in the living area throughout the house was properly installed and sufficient.  The source of the humidity problems resulted mainly from the small crawlspace area that was underneath the Northeast corner of the home. 

While the blower-door was still running, we entered the crawlspace from the basement and inspected the foundation walls and the bandjoist for air leakage and evidence of moisture intrusion.  It was immediately apparent that the crawlspace was very humid and that standing water was present.  It was so humid, in fact, that the foam board insulation on the foundation walls had detached from the walls because the glue adhesive had become too saturated with water. 

In addition to this, we could literally feel outside air coming in through cracks and morter joints in the foundation walls.  It's pretty easy to say that if air can pass through a wall that water can most certainly pass through as well.

We concluded that the cause of the humidity and temperature problems that remained directly resulted from the excessive moisture in the crawlspace, which was due to cracks and openings in the foundation walls that allowed rainwater to seep through, due to crushed underground drainage lines in the front yard.  Detached foundation insulation was allowing excessive heat loss as well.