Photo of Mold on a Ceiling
Image by Infrogmation | CC BY 3.0

In this post, you’ll discover some of the most common factors for what causes mold in a home.

In the simplest of terms, mold thrives in certain conditions and these have to be present in order for mold to grow.

If you can find the root of the problem and fix it, you can eliminate mold from the surface.

The most common place you’ll find mold will have a combination of these attributes:

  • Mold spores (this spreads the fungi)
  • Food source (such as wood, drywall, cotton, etc.)
  • Warmth (mold can’t survive in cold temperatures)
  • Time (it takes at least 24-48 hours for mold to start growing)
  • Moisture (humidity or water leaks)

Out of everything listed above, moisture is the key attribute you have to keep an eye on the most because all of the other traits are continually present inside a home.

What you’ll find is that mold issues tend to only show up when you have a moisture problem. Keep reading below to learn what the most commons cases are in this respect.

High Humidity Levels

With humidity comes moisture and if you live in an area that has high humidity rates you may notice a recurring issue with mold.

The same thing is true with areas that receive a lot of rain. Mold thrives in wet conditions and the more water that is present, the worse the problem can become.
A cheap fix for humidity problems is to install a dehumidifier inside your home.

This will regulate the levels of moisture in the air and keep it at a level that mold cannot grow.

Water Leaks

Since mold feeds off of moist surfaces, having a water leak of any kind is a breeding ground for infestation.

Often, leaks reveal themselves by creating water stains on drywall or flooring. Keep an eye out for these signs and do what you can to quickly fix the problem.

Otherwise, the mold will spread and produce more mold spores that can move to other areas of your home.

Sometimes you don’t know about a water leak until it’s too late. If a pipe is leaking behind a wall or in an attic you may not discover it until mold has already started to grow.

The best thing to do is to check the walls and ceilings of your home regularly, especially below the attic.

If it doesn’t rain often where you live, a leaky roof may not be discovered for several months until it gets noticeably bad. If you can inspect your attic, do so on a quarterly basis.

Poor Ventilation

Another common reason for what causes mold in a home is having poor ventilation. You often see issues like this inside bathrooms, basements and crawl spaces, and sometimes kitchens.

If parts of your home are not properly ventilated then moisture and humidity that builds up inside these spaces have nowhere to escape.

This creates a pocket of stagnant, moist air for mold to live on. (For technical information on various ways on how homes can be ventilated, check out

The easiest solution for maintaining a mold-free space is to ensure that it is properly ventilated.

If issues pop up in a bathroom, make sure that the ceiling fan is operating correctly.

Check to make sure that it’s not clogged up with dust and debris, preventing it from working efficiently. If you don’t have a fan, then keep a window cracked and the door open after taking a shower.

This will allow the moisture to escape and not create an environment for mold to sprout.

If you’re noticing an issue in a crawl space, check to make sure that the venting system is not blocked or clogged with debris.

This is usually the culprit. If the issue persists, then you may need to have a professional look at the situation and determine if the original venting system was sufficient for the size of the crawl space.

The same thing goes for a basement.

Check the venting system to make sure it’s free and clear.

Another way to keep mold under control is to add an air purifier to the room.

This machine will attack mold spores in the room by trapping them inside a filter or zapping them with an ultraviolet light.

This inexpensive device is a great investment for people who have basements that continue to get mold problems.

Take a look at this post with the best mold air purifier reviews for your home.

This device is one of the best methods for how to get rid of mold in your house quickly.