Higher Level Mold Training?

Hi Guys:

I am having difficulty and don’t know where to turn. Can anyone make a recommendation please?

In the past few years I have had 2 “mold smelling” buildings that I can’t find the culprit in. Both buildings had old water damage that was repaired. There is no visible mold, or even elevated mold spores counts. In fact there is no smell, until the humidity gets high. Obviously there is some hidden mold behind something that will not allow spores to pass through, but does allow mold gas to pass through.

I feel as though I am at a loss in finding the problems in these 2 buildings, and didn’t charge for the inspections. However can anyone help me to get the training to go to the next level?

Dale Collins

Have you tried a particulate counter?

You may also have to do an intrusive inspection, have you done any wall samples?
Mold may be on back side of drywall, when humidity gets high it may start giving of that wonderful smell.

Hi Guys:

I appreciate the suggestions, and agree these are things to consider. However, we have a particulate counter, and now only use it for mold remediation, when we have an air scrubber working. Otherwise we have learned that it gives readings that have no meaning for mold, and can scare people. Please note, there is no elevated spore count. The counter does not pick up gas.

In regards to behind wall samples, I agree. But to not know where to begin would require sampling from virtually every cavity in comparison. What I am trying to determine is, what to do in these situations? Is their advanced training? I have taken different 2 schools mold inspection course, a mold remediation course and many related ones (see website under resume/cv). I know one answer is to buy a mold dog. But like noted above, I have only had 2 occasions over the year that I could not find the problem and it would not be worth it.

Has anybody else had this problem? Is this more a question for the IAQ Association?


If you are still getting a smell, you got moisture somewhere. Try taking a thermal camera and a moisture meter around and find the moist area. Take an inner air sample inside the wall or ceiling cavity that has the most moisture.
You will probably not learn stuff such as this in class.

Hi Braun:

Thanks for the help.

Please note my website, these are things that I have/do (I’m also Ir certified). High humidity alone activates these odors. This is normally dormant mold that is behind something, probably sheetrock. Ir and moisture meters are good tools. But are they good to find old mold that is covered, where there is no water problem?

All that I do are flooring/moisture/mold inspections so I use these tools a lot. Has not anyone else here ever seen this problem? If so maybe that’s why there are no higher-level schools? If anyone has, or knows of one please email me.

[FONT=Verdana]I agree in the wall sampling (or a mold dog) is the way to go, but my cost in testing every cavity would not make it feasible. There is no moisture content variation, because these are old (many years ago) water damaged buildings that were dried and repaired, and the mold was covered over. Someone surely must teach of a way to hone in on the source?[/FONT]

Dale Collins

There is a guy in my area that has a mold dog you may want to have him travel.

Just a thought

Hi John:

And it’s a good thought, if he just was closer.

I have checked, there are none in my area. One 100 miles away does’nt answer my calls, they must have gotten out of it.


If you have high humidity problems, than the drywall would have high moisture. Any drywall with high moisture needs to be removed. Mold can grow on drywall at 12 percent. I guess I do not understand your problem.

There are several different ways you can try to detect mold in hidden locations, however most of them are considered invasive procedures that will cause damage to the finished surfaces.

Intracavity wall and ceiling samples are going to give you the most accurate information of all the methods, but it should be realized that it will not pinpoint the problem to an exact location.

Another method is to use a carbon dioxide detector…note I said dioxide, not monoxide. Molds use oxygen in order to grow and give off carbon dioxide as a byproduct just like people. Drilling holes in the wall and inserting the sensor will give you data where you can map out any high areas that are suspect and later cut larger inspection holes.

Mold growth also generates a small amount of heat as the colony grows. You can cool the room down and look for heat signatures depending on how sensitive your infrared camera is and the resolution.

An experienced mold inspector should be able to look at the home and find conditions conducive of mold growth. Sometimes previous repairs have been made to correct the contributing factor that the homeowner does not tell you about, or has no idea were undertaken. Look at the age of any suspect areas and try to determine if a recent repair has been made. If the materials do not appear to be original in an area, there is a good chance that changes have been made. Begin looking in the home where water might have gotten to from any suspect areas. Keep in mind that moisture can come from leaking plumbing supplies or drains, air conditioning condensate lines, improper ventilation that result in condensation formation, missing or insufficient insulation, and the way an occupant lives in the space.

People are always worried about ripping into finished walls in order to find mold growth. For some reason, everyone thinks that wall surfaces are more expensive than gold. Remind clients, drywall is cheap and easily replaced if they really want to get to the bottom of the issue once and for all.

What resolution of camera would be needed to detect a mold heat signature?

I have been able to to use a 160x120 camera using active thermography. The results were less than perfect and I would recommend using something a little higher resolution like 320x240 to prevent grainy images that are hard to intemperate from low delta T when using this method.


Hi Scott:

I’m truly grateful. It sounds like you’ve “been there done that”. Please refer me to the school where you learned this, so I can take their course also. IMO it’s always good to have the schoolbook to quote from when we do inspections that may end up in court.

Had these 2 buildings not have had previous water damage that was dried & covered there would be no problem. But since the entire buildings had been flooded years ago, (not a localized leak) the whole building requires more than a normal mold inspection, and that gets into costs that the Consumer does not want to pay for. Not unless they can go back on the Restorer, or Insurance co. I doubted they could after this long of time so I did not want to do invasive testing.

The CO2 information is new to me, and I like that idea. Small holes in the wall and no lab fees are a lot better than the alternative. I found several CO2 meters available online, but could you please refer me to a starter one? I can also then use my borescope to look into the small hole needed for the CO2 probe.

What I can appreciate about what you are saying is; whereas most here think I need to look for “wet” areas, old dried mold that gets humid will be warmer, not cooler as in new mold from recent leaks. Is that correct? My camera is “interpolated” to 180 X 180 resolution. As far using it, slightly warmer areas can only be seen in areas that could be attributed to insulating conditions.


You need to do a particle track to the source. This can be done while no one is in the building. The proper way is with a P-trak investigator. When you find the high level than open the wall and investigate in this area. This will save you money and is what I have been doing for years. A good investigator will have others tools at his disposal.
CO detector
Co2 Monitor
Mold Sampler for walls
Air sample for allergens
GAS detection
VOC detector.
Moisture Meter
Good scope with camera.
If you cant find it this way it does not exist.

Hi Kevin:

Good to hear from you. What is a particle track? Are you sure you can find gas that is sealed behind something (not spores) with it?

As far as gas odor inspections go, I have worked with Air Quality Services Inc. of GA. on a like project. For them to rent me the collector and determine VOC’s starts @ $2500. If the Consumer really wants to spend money, that is where the buck stops, but it still does’nt tell where the mold is.

Scott above seems to hit on somthing with the CO2 device, but please I am asking “where the advanced shool is that teaches this”? I don’t have a problem with doing these things, I just want to be able to quote the Expert source if it goes to court.


You clients want answers but does not want to spend money. Tell you client to go to the doctor and tell him that his chest hurts, but does not want to spend money on EKG, Xrays, MRI or blood tests…but wants to know exactly what is wrong.

Your client has unreal expectations for what can be done. The schooling does not matter. There is absolutely no substitue for cutting the walls and at least using a borescope. How much could that cost?

Hi Kevin:

I appreciate your advice. Please what is a particle track? Are you sure that it will find mold gas (not spores) from mold that is trapped behind materials?

I can understand what Scott is saying above about CO2 testing, and I have no problem with doing that. But please reread my question. I am asking for an advanced school, so that I can quote the source in a legal situation.

When I can’t quote a source, and the Customer has “money is no object” syndrome, I go to another company. I have been involved in a like situation when I hired Air Quality Sciences Inc of GA. IMO they have the best true gas sampling device for this. To rent the collector from them, and to have the lab work done starts @ about $2500. But it still only tells what the gas is, not where it’s coming from. But it does allow a search by process of higher concentrations.

Here is what I intend to do. In that I have only recently started posting on InterNACHI I did not know that IAQ2 has a board of their own. Tomorrow I will make a post on it instead. But please Scott, if you see the last post that I made, (after yours) could you please help with the questions that I have, and any source that I can quote?



Please I am only trying to find a school.

No one said the Customer did not want to spend money. I do not charge money until I find the problem that I am sent to find. And I will not waste money in the process. I do not do Home Inspections. I only do investigative inspections that lead to someone being at fault. If I can’t find the fault there’s no charge (only happened twice) and I don’t want it to happen again…

Please can anyone quote the sources of their resources?


P.S. I did see that there is a IAQ2 board, and I will take the question there maybe tomorrow. However if Scott (whom seems to have some good advice) sees my questions to him, can he contact me?

“Had these 2 buildings not have had previous water damage that was dried & covered there would be no problem. But since the entire buildings had been flooded years ago, (not a localized leak) the whole building requires more than a normal mold inspection, and that gets into costs that the Consumer does not want to pay for.”

Sorry your post had me confused it sounded as if the client wants answers and did not want to pay for them…