Leaky air-conditioning duct joints, especially those running through a hot attic, create a moist environment for mildew.

Solution: Seal all duct joints with the special flexible mastic available heating and cooling supply stores.

Problem #2

In warm environments, impermeable vinyl wallcoverings can trap moisture-laden air as it moves from the warm exterior to the cooler interior. Mold degrades the drywall and adhesive behind the vinyl wallcovering.

Solution: Use paint or apply wallcoverings with permeable paper backings that don't trap moisture on exterior walls.

Problem #3

When washing machines in a room without a floor drain overflow or hose connections burst, water with no point of exit will soak into adjacent carpet, drywall and insulation.

Solution: Always provide a floor drain near the washing machine. Install an overflow pan directly under the machine or install a 1-in. lip at the doorway to contain overflows in main-level or second-story laundry rooms. (An overflow pan is available for about $125 plus shipping from AMI, 800-929-9269.)

Problem #4

Water-resistant drywall used as a the backer quickly degrades once subjected to moisture.

Solution: Install cement backer board, which will remain structurally sound even if repeatedly subjected to moisture.

Problem #5

Poorly ventilated bathrooms allow surface mold to grow.

Solution: Install a bathroom fan (or at least, open a window) to exhaust moisture. Remove surface mildew by scrubbing the area with a 1/2 percent bleach solution. When the area is dry, prime it with an alcohol-based, white pigmented shellac, such as Zinsser Bullseye, and use a paint containing mildewcide.

Problem #6

Poorly constructed crawlspaces promote mildew growth. Bare earth floors transmit huge amounts of moisture.

Solution: There are many regional differences and solutions. Cover bare earth with 6-mil poly sheeting. Heat, cool and humidify the area the same as the rest of the house.

Problem #7

Freshly cut firewood stored indoors emits huge amounts of moisture.

Solution: Store it outside.

Problem #8

Humidifiers (especially reservoir-type central units and portable units) provide both a growth medium and a distribution system for mold and mildew.

Solution: Clean and treat the reservoir often with an antimicrobial solution, available at most hardware stores.

Problem #9

The condensation pan directly under the coil of your central air conditioner can harbor mold.

Solution: Before each cooling season, clean the pan with a 1/2 percent bleach solution and make sure the continuous drain is working.

Problem #10

Finished concrete basements that haven't been thoroughly waterproofed from the outside are problematic. When moisture migrates through the earth and non-waterproofed concrete walls, it can get trapped behind vapor barriers, carpet, layers of insulation and drywall.

Next Page / Back to Combating Mold