Both types require analysis by a certified laboratory. In some cases, mold samples may be tested by your local health department. Air tests are performed to determine if mold is hidden in the house. Mold spores float in the air until they find an area conducive to growth.
If the surface is damp, mold spores can take hold and grow. Mold usually develops in dark, damp places, and spreads slowly over time. It may be some time before you notice the presence of mold, especially if it is forming in areas such as the attic, basement, or inside walls. If you have the home professionally inspected before you buy it, your home inspector may see obvious signs of mold or water damage.
While it's not the inspector's job to look for mold, most home inspectors will mention obvious signs of water damage and possible mold. And, since the inspector will rummage through spaces you couldn't see, he might see things you wouldn't see. For more information, see Nolo's article, How to Get a Home Inspection. This is why mold growth is one of the main things home inspectors look for when completing an inspection.
A professional mold inspector usually performs different types of mold tests to ensure the most accurate results. If mold is detected, the inspector will try to find the source of moisture that is causing the mold and will talk to the landlord to develop a remediation plan. A typical mold inspection involves the inspector talking to the property owner about any areas where they have seen mold or where there have been moisture problems or water damage in the past. With growing awareness of the potential hazards of mold, home inspectors are trained to conduct a thorough mold inspection.
The inspector will also perform a visual inspection of the rest of the home, focusing on areas where mold is known to commonly form. However, if this inspection is for mold air sampling only, the inspector will search for areas of interest using their knowledge and equipment. If you have questions about the cost of a mold inspection for your home or packages, contact your local home inspector for more information.