how many air samples are enough


I just spent in excess of $1000 on 5 air samples and an inspection report. The report shows elevated levels of Penicillium/Aspergillus (2700 spores/cm3 -1st bedroom, 2,300 - 2nd bedroom, outside control - 0) and Cladosporium ( 5,600 spores/cm3 - 1st bedroom, 3,600- 2nd bedroom, outside control - 2,200). The mold inspector now wants to test 5 (!) more air samples in the house. He is also recommending professional remediation on the bedrooms.

From what I understand, the CDC and EPA do not recommend air sampling. I don’t see the point in more air testing. The house is 100 years old. We know it has moisture issues, because we live in the foggy part of California. The windows are also single pane and the unit has very old wall to wall carpet. We have not been provided a real explanation as to the cause other than that there have been minor leaks in the building (these were always fixed), and that there is no primary cause of the mold. It is a rental property and the occupants do not take care of it. There is obvious mold growth around the window sills, glass, and frames. It has been recommended that we install double pane windows and rip out the carpets.

My questions to you inspectors - what value will more air testing do? It’s obvious there is a mold problem, at least on the windows. Obviously, air testing by the windows in other rooms (which is what they are proposing) will show elevated counts. Couldn’t we strip the carpets and install double pane windows in the rest of the house and do without the pricey professional remediation. I don’t see the need for it. Is the inspector just trying to CYA, because tenants are complaining that they are “sick”? And yes, I know mold is gold.

Your frustration is understandable. There remains much hysteria about mold and its significance, owing in part to the wide variance in people’s sensitivity to it and the money to be made testing for and remediation of when it is found.

The thing about rental properties is that the tenants expect the landlord to take care of the property, even if their stewardship is below the terms of the lease. If there’s a moisture problem, they see it as your problem, not theirs, until such time as it affects them.

As to the causes of the problems and the motivations of your inspector and tenants, it would be speculative at best and likely irresponsible for any of us here at the forum to comment on. I would posit that the inspector is trying to help you cover your a**, but you are tiring of the expense.

You need to seek the opinion of professional whom you trust and can come and look at the property. Correctly identifying the problem areas and their causes might prove costly, but the alternative is a scatter-shot approach to remediation that could end up costing you more in the long run.

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In my opinion you have already determined there is a mold issue in the home. I don’t see a legitimate reason for additional test. My next course of action would be to contact a reputable/professional mold remediation company and/or an indoor air quality professional.

I agree with Chris and William to some extent, but have a different ‘next course of action’ in mind…

Here’s the bottom line… you have a mold issue because you have moisture intrusion issues. SOLVE the moisture issues, and the mold issues will become negligible. There is mold EVERYWHERE! It is a fact of life. We typically only test when there are health concerns without visible colonies of mold, there are people that are hyper-sensitive to mold so the species is medically important to be known, and/or as in your case you are renting to the general public where significant liability and risk is involved.

  1. Hire a contractor to make all necessary repairs to stop all sources of moisture intrusion,
  2. Develop a plan to reduce the effects of high RH from the ‘foggy’ atmosphere, ie. whole home dehumidifiers,
  3. Hire professionals such as an Industrial Hygenist to re-test AFTER the moisture problems are solved, and performe any necessary cleanup/remediation of still active or excessively large dormant mold colonies. These professionals can also advise further on any future actions you may need to take.

These professionals are ALWAYS licensed and insured as required by all states. DO NOT hire anyone that is not able to show their credentials for verification. Legit professionals will not be offended by your asking to view their credentials.

I understand this may sound like a lot of work, and could be very expensive, but you are a landlord and the health of the structure is directly in your hands. Imagine the repercussions if you ‘shortcut’ this and a tenant becomes ill. You may wish to do a ‘check-up’ of your insurance to ensure you have appropriate coverage going forward. Good luck.