High Humidity

Check the humidity levels in your home using a hygrometer, an inexpensive device that serves as an indoor thermometer and humidity monitor. If your home consistently averages high humidity levels of 55% of more, you have an ideal environment for mold to grow, especially in a warmer indoor air environment.


Efflorescence is a crystalline deposit of salt left behind by the evaporation of moisture that has been moving along porous surfaces, such as concrete. It is typically white, is often found in the basement on the foundation of a home, and indicates there has been flooding in this area.

Painted Foundation With Bubbling

Many people paint over efflorescence on the foundation of a home. When renting or purchasing a new home, you should always question why the foundation has been painted, particularly if there is visible bubbling of the paint. Bubbling indicates that water seeped in through the porous foundation material and became trapped behind the paint.

Ponding Near Foundation

Ponding near the foundation or water that does not drain away from the foundation can cause flooding in the basement or crawl space, creating a damp environment that contributes to mold growth in the home. A professional contractor should be hired to correct the pitch so water flows away from the foundation.

White Discoloration On Joists

Often overlooked, a white or gray tinted discoloration on joists indicates mold growth. Gently scraping the joist will reveal it’s true color in contrast to the growth. This is commonly found along the joists in a crawl space or basement and is often Penicillium /Aspergillus type mold.

White Discoloration In Rafters

Powdery or filmy white discoloration in the attic rafters indicates mold growth. Moisture in the attic is caused by leaks and/or poor ventilation. Moisture issues must be corrected before mold can be removed with an approved biocide or it will quickly return.

Thermal Bridging

Visible studs through the sheetrock is evidence of thermal bridging and indicates there is old or no insulation in that area. This can lead to moisture penetration in building components and contribute to mold growth in the dwelling. Insulation should be replaced or installed.

Water Damaged Furniture

Discolored or cloudy spots or warping on the base of furniture suggests past flooding. Some furniture will also display signs of swelling. If wooden furniture has become damp enough, rot can begin within seven days. White blooms indicate that mold has begun to grow.