How Does Mold Spread and Is it Contagious?

Mold can spread throughout a house or between properties more easily than most people think. In this article we will discuss how mold spreads and what you should do if you are moving out of a house with mold to prevent it from contaminating your new house.

Does Mold Spread Through The Air?

Yes, mold spreads via mold spores which are kind of like “seeds” that are so small that you cannot see them. These spores travel through the air and can form new mold colonies if they come into contact with a moisture and a food source. This includes spreading in walls where it cannot be seen. In many cases mold will spread upwards in a property due to something called the “stack effect” or “chimney effect”. When the outdoor temperature is much colder than the indoor temperature, buildings (especially tall ones) experience an effect where warm air rises and escapes through openings in the upper floors. With this warm air also comes mold spores, dust mites, and odors.

How Far Can Mold Spores Travel in The Air?

Mold spores are tiny (between 2-100 microns) and can survive indefinitely if not effected by outside sources. Therefore even the lightest breeze can move mold spores long distances and into buildings. Mold spores can be brought into a house from outside sources through open doors and windows, HVAC systems, or hitching a ride on objects. They are in fact in every building so they are only really a problem if there is a lot of mold spores or if there is moisture present in the property for them to land on and form a colony.

Does Mold Spread Fast?

Yes, mold can begin to grow within 24-48 hours after coming into contact with a moisture and food source. For this reason it is important to hire a professional right away if you have any sort of leak occur in your property.

Is Black Mold Poisoning Contagious From Person to Person?

No, mold illness is not contagious from person to person as it is not a virus or bacteria. The illness you feel from the mold is more similar to an allergy than it is a contagious sickness. The health issues that mold causes are mostly from mycotoxins and mold spores which are not contagious.

Can Mold Spores Travel on Clothing?

Yes, mold can grow on clothing and mold spores can stick to clothing and potentially bring mold into another property.

Can Mold Spread From House to House, Apartment to Apartment, or Condo to Condo?

Yes, mold can spread from one home, apartment, or condo to another in various ways. The most common of which is via mold cross contamination. Essentially, if you have mold in your currently property, then you should assume that all of your personal belongings have mold spores on it too. So if you are moving out of a house with mold, it’s important that you get your items throughly cleaned by a professional or simply dispose of them and replace them with new items. This includes everything from your clothing to your furniture.

Do You Have to Throw Everything Away With Mold?

No, you don’t need to throw everything that has mold on it away, but you do need to get it cleaned and get it rid of mold. That being said, if you want to be on the safe side, disposing of mold contaminated items is much safer than trying to clean them. That’s because if you clean the items improperly, they may still have some mold on them and this mold can spread to your new dwelling.


Mold can easily spread from place to place if it is not dealt with properly. If you have mold in your property, it’s important to consult with a professional like us to make sure you don’t spread it from one place to another. Call us now for a free inspection and estimate!