No-one can guarantee 100% that a home is mold-free, and this is why:
If we tested every room of a typical 3 bedroom home, we would have, as a minimum, 3 bedrooms, 2 baths, a kitchen, a living room, a dining room, and a laundry room. That’s 9 rooms plus the outdoor sample making a total of 10 air samples. Although we could test every room of a house, the cost would be too prohibitive because each sample costs money. And, then each room has four walls where potentially a mold problem could be developing, but the contamination is not large enough to affect the air quality of that room—at that time. Then, within a few weeks the contamination could grow and enough mold spores could come through the wall. This is why no one can guarantee that a home or building is mold-free.
Even though it would be too costly to test every room of a home for mold, the mold inspector can recommend enough air samples to have good coverage. We advise clients that the accuracy of pin-pointing a problem area decreases as the number of samples decreases. But, when clients want less samples than our recommendations and they are paying the bills, there is not much the mold inspector can do.
Mold testing provides a snap shot of the air quality at a point in time.
Mold testing helps to scientifically determine the air quality of a home or building—at a particular point in time. The client authorizes both the manner of sampling and the total number of samples taken by the mold inspector.
Do not trust anyone who claims mold testing can prove a building is mold-free. There are many situations beyond the control of the mold inspector and his clients that can affect the results. For instance, the seller may leave the doors and windows open for an extended amount of time prior to mold testing, or he turns off air cleaning devices just before the mold inspector arrive. This will obviously affect the sampling results in the event a mold contamination is present.
Mold testing provides an indicator of the air quality in relation to mold at the time of sampling, as conditions can change over time. We must remember that mold can start growing within 24 to 48 hours when a moisture source is present. There is no guarantee that mold does not presently exist in other areas of a home/building, nor do the results guarantee that conditions will not change in the future.