Too Many People Living in Too Small an Area
Most molds love humidity above 55%. The hotter and wetter it is, the better some molds like it. If you see condensation on the inside of your windows you probably have a humidity problem. The use of a temperature humidity gauge may help you to monitor humidity. Turn on exhaust fans or open windows to reduce interior elevated humidity.
Vent the Clothes Dryer Outside
Putting a sock or “dryer bag” on the dryer exhaust inside your garage, crawlspace, or home laundry will elevate humidity. All vents should reach outside air.
Exhaust Fans in Bathrooms and Kitchens that Vent Outside
All exhaust fans should be equipped with a timer or humidistat or motion sensor so they stay on for 20 minutes or until the humidity is 52% or lower. All vents should reach outside air.
Here’s a simple test to determine if your ceiling exhaust fans are working: take 1 square of toilet paper and place it under the vent grill. If the paper sticks to the grill, it’s working properly. If not, that’s a sign there is a problem.
Preventative Maintenance
Other than plumbing leaks, roofs and gutter systems are potential water sources that can leak and create mold growth.
Have a professional roofer inspect your roof annually.
You should always confirm downspouts drain 18 inches away from the foundation.
You should always check to confirm downspouts are connected and not leaking where they shouldn’t. Use a garden hose to add water to your gutter system and then look for leaks. Gutter guards are a preventative maintenance recommendation.
You should always check landscaping water system are not hitting the building. Drip irrigation is recommended.