The first thing a mold inspector will do is perform a visual inspection. They’ll note any areas that appear to have mold, musty odors, or elevated moisture levels.
They’ll then take an outdoor sample of air to compare with the indoor spore count. If the spore count is higher inside than outside, they’ll know there is a problem.
1. Visual Inspection
Mold inspections begin with a thorough visual examination. Mold inspectors will walk around your home, checking every room and even crawlspaces for signs of mold and moisture problems. A quality mold inspector will also use a moisture meter and thermo imaging device to pinpoint damp areas of your property that might be causing problems.
Once they have a clear picture of what the problems are our mold inspectors will carry out further sampling to identify what kind of mold you are dealing with. Surface samples can be taken using a tape sample or a swab sucked from the suspected surface for laboratory testing. This method helps to narrow down the type of mold you are facing so that a remediation plan can be put in place.
Air sampling is another technique that our mold inspectors will use to determine if there are mold spores in the air that can be seen or not. These spores are circulated through the ventilation system in your home, and our mold inspectors will take air samples to evaluate their levels.
This can be done using a portable air pump that will collect the sample from inside the home, or a more invasive method which involves drilling a hole in the wall and deploying an inner-wall sampling attachment. Before your appointment we advise that you close your doors and windows as this maximizes the concentration of air containing mold spores, making them easier to detect. If your HVAC system is running it is also a good idea to turn it off for the duration of your appointment, as this could dilute background levels.
During a visual inspection the mold inspector will ask questions about the symptoms you have been experiencing and about the history of moisture issues at your property. They will also want to know if anyone in your household has any allergies or sensitivities to mold.
2. Tape-Lift Sampling
Tape sampling is a non-invasive and fairly easy method of collecting a sample from surfaces suspected to be affected by mold growth. It is a very cost-effective technique that can be utilized by InterNACHI inspectors and certified industrial hygienists alike. It can be used to test a wide variety of materials including walls, floors, carpeting and furniture. Often, tape samples can be collected and analyzed within a few hours of being taken.
A typical tape sample consists of a clear plastic or glass slide that is pre-loaded with an adhesive. A piece of standard clear tape or a commercially available kit is then placed over the suspected surface. The surface is pressed against the tape for a few seconds in order to collect an impression of the visible mold and/or discoloration. The slide is then inserted into the case or cassette and sent off to a lab for analysis. This method is very simple and generally doesn’t damage surfaces or furnishings when done properly.
The results from a good tape sample can provide the investigator or occupant with important information. It can determine if a particular genera is present on the suspect material, its viability and spore counts. However, it should be noted that if a tape sample is smeared or contaminated during collection it may not provide usable results. This is why a careful and thorough visual inspection is essential prior to attempting a tape sample.
During the sampling process, the inspector should wear a pair of clean gloves and a respirator rated N-95 or higher. The fungi spores found on mold contaminated surfaces can pose a health risk to occupants if inhaled. The inspector should also follow the Chain of Custody protocol when taking a tape sample to ensure that the results are accurate and can be trusted.
3. Air Sampling
Air sampling is an important component of a mold inspection. It can be used to identify hidden contamination and to compare particle levels and air quality between two areas. The inspector will take one sample from each area of concern and a control sample from the outdoors. This allows the inspector to see if there is an increase in particles from the problem area or a decrease in particles in the control area.
The air samples are taken with a small pump that draws the air through a cartridge that has a slide inside of it. The sampler is run for a specified amount of time and at a consistent air flow rate to ensure consistency in the data collected. The pump is calibrated to pump no more than 75 liters of air per minute, which is about the volume of a small bathroom. The air is then collected on a slide which is deposited into an Airosol® or other sampler. The spores on the slide are then analyzed at the lab.
Non-viable spores can be used to help the inspector find potential sources of mold by identifying long chains of spores that normally break apart as they move through the air and would indicate a larger hidden source. Air samples can also reveal the presence of toxins called mycotoxins which are produced by Gram-Negative bacteria and cause Chronic Inflammatory Response Syndrome (CIRS). The ERMI scoring system uses this type of testing to determine if a house has toxic mycotoxins present in it.
Surface sampling can be done by swabbing any areas of concern with visible apparent mold. The swab is saturated with a liquid preservative and placed over the mold growth. A unique sample number is recorded on a Chain-of-Custody form, the swab is then inserted into the tube, and the cap is secured.
4. Surface Sampling
When visual inspections cannot determine the cause of mold growth, surface sampling may be helpful. It involves obtaining samples of surfaces in your home and analyzing them to identify the types of mold present. This can help determine whether visible mold is in fact actual microbial growth and provide evidence of the extent of any such growth. This method can also indicate if there is a problem with airborne mold spores.
To take a surface sample, your inspector will take a clear sticky tape and apply it to the questionable surface area (with the adhesive side in contact with the surface). Then the tape is removed and placed on a clean microscope slide for examination. This technique can detect both viable and non-viable spores, and can identify the genera of mold growth to the level of hypha fragments and reproductive structures.
This method is very quick and requires little to no set-up time. It is also relatively inexpensive compared to other methods of collecting mold samples, and it provides a good indication of the type of mold in an area. It cannot, however, identify the specific species of mold present, so it is best used in conjunction with other sampling methodologies.
When a surface sample is taken, the swab should be gently pressed against a one-inch square area of apparent mold growth. Once the swab is taken, it should be carefully wiped clean and inserted back into its tube with a cap. A chain-of-custody document should be completed with the sample number, location, date and time of the sampling, and mailed off to the laboratory for analysis. The inspector should also provide the client with a description of the results.
5. Laboratory Testing
A home inspector will visually inspect your house for areas that may be prone to mold growth. If a problem is suspected, the inspector will take air and/or surface samples for lab analysis.
They will use a moisture meter to determine if there is excess moisture in the building materials that may cause mold problems. This can be very helpful for identifying the source of the mold and determining whether or not it is a health hazard.
If you are having a mold inspection, you should close all the doors and windows to your house. This will maximize the accumulation of spores in one area, making it easier for your inspector to identify them. The HVAC system should also be shut off to prevent the circulation of spores throughout your house.
A professional mold inspector will test the air for a spore count, which provides a baseline of what the concentration of spores should be in your house. They will then compare that to a sample taken outside your house to find out if there is a higher concentration of spores inside than outside.
They may also take a surface sample using either tape or a swab, which will be sent to the lab for identification. Both types will provide a list of live and dead mold spores that are present in the sample. They will also identify the type of spores that are present.
This is a great way to pinpoint the source of the mold problem, especially in places that are hard for a visual inspection to see. This can be very helpful in finding out if the spores are toxic or allergenic, and how severe your mold issue is.