Winter Mold Testing

I am working on my mold cert and it says:

If the ground is completely covered with snow, outdoor air-pump sampling should not be performed.

That's like 6 months out of the year for us.

There must be a different protocol for snow cover and control samples or are we just not testing from November - April?

Taking an outside sample in the winter is advisable with the following caveats. 1) If 80% snow cover then DO NOT take outside sample, 2) Take sample outside down to minus 15 degrees F - the media does not have water in it and will not freeze, but keep the sample in your inside coat pocket or pants or in warm house or truck where the media will stay pliable before taking the sample. This should be easy since the outside sample is the FIRST sample that should be taken if at all possible. 3) If snowing HARD then DO NOT take a sample, otherwise do.

I wish there was a way to take a control sample with 100% snow on the ground. After our first few snowfalls we will not see ground until mid March.

What do you recommend for homeowners that are buying, want to test for mold, but we have 15 inches of snow on the ground.

Also, I see some instructions that say to take one outside control sample and the InterNACHI test says to take two control samples. One on the outside front of the house and another in the rear.

This is not a problem, it just does not seem to be the standard that I am seeing in my area.

One outdoor control sample is fine. Will get you very scientific answers to the rest of your questions shortly.

This message was edited 1 time. Last update was at 10/31/2014 10:52 AM EDT

Taking two samples outside is a great idea for science and I certainly recommend it if you can. However, most clients do not want to pay for it. One outside sample is what overwhelming number of home inspectors take.

Taking a sample outside with over 80% snow cover can give great results, but can be negative for mold and most debris.

For a purchase of a new house, an outside sample can be taken with greater than 80% snow cover for one important reason, i.e., a relocation, mortgage company, etc. may require it. In this case, do take an outside sample and let the laboratory sort out the details of interpretation.

Winter Mold Sampling - What a great question!
There is a lot of misinformation running around about this very topic. Let's get to some facts first:
1) The capture media does not easily freeze. It is good down to around minus 15 degrees F. There is no water in the media. It will stiffen so keep it warm, like inside your coat, in a warm truck, house or inside pocket of a coat right before sampling.
2) Even in places that are cold and at or near freezing during the winter mold can still grow and sporulate. There are too many reasons for this to go into here, but there are freeze/thaw cycles and long distance transport happening all the time. There are several ways in which mold is dispersed that come into play also.
3) DO NOT take a sample in a garage. That is a garage sample.
4) DO NOT take a sample in a "Clean / Non-problem" room. How do you know it is a "Clean"?

SUMMARY
Mold is almost always in the air and sporulating, even in the winter and with lots of snow cover. Take a sample of the outside air with a warm cassette. You may want to short cycle (take only a 5 minute sample) to keep from having the media harden due to cold ambient temperatures.

BTW - DO take samples during rain, before a rain and after a rain. I keep hearing advice regarding this topic and it is all wrong. The only way I would not take an air sample outside in the rain is if it is a complete downpour. You may want to wait it out.

I hope this helps!

That's awesome information! Thanks Dr. Shane!

Also, "sporulate" is a cool new verb I learned today.

Nathan wrote: the outside sample is the FIRST sample that should be taken if at all possible.

can you pls explain this?

docshane wrote:Winter Mold Sampling - What a great question!
There is a lot of misinformation running around about this very topic. Let's get to some facts first:
1) The capture media does not easily freeze. It is good down to around minus 15 degrees F. There is no water in the media. It will stiffen so keep it warm, like inside your coat, in a warm truck, house or inside pocket of a coat right before sampling.
2) Even in places that are cold and at or near freezing during the winter mold can still grow and sporulate. There are too many reasons for this to go into here, but there are freeze/thaw cycles and long distance transport happening all the time. There are several ways in which mold is dispersed that come into play also.
3) DO NOT take a sample in a garage. That is a garage sample.
4) DO NOT take a sample in a "Clean / Non-problem" room. How do you know it is a "Clean"?

SUMMARY
Mold is almost always in the air and sporulating, even in the winter and with lots of snow cover. Take a sample of the outside air with a warm cassette. You may want to short cycle (take only a 5 minute sample) to keep from having the media harden due to cold ambient temperatures.

BTW - DO take samples during rain, before a rain and after a rain. I keep hearing advice regarding this topic and it is all wrong. The only way I would not take an air sample outside in the rain is if it is a complete downpour. You may want to wait it out.

I hope this helps!

Thank you very much.

Question, if there is a ton of snow will the control cassette show less mold because it is really just air blowing off the snow? If this is the case would the inside air sample have a greater margin of mold than if tested in the summer in comparison?

The majority of us have whole house humidifiers in our homes that we run from about now - March. Any issues with these systems and mold testing?

Thanks for your help

I'll have to test this on my house in the Winter and once in the Spring.

I think Juan was looking for this thread.

Nathan wrote:I think Juan was looking for this thread.

Yep. Thanks! I initially skimmed by it because we don't get much snow here

Pete Campbell wrote:

Nathan wrote: the outside sample is the FIRST sample that should be taken if at all possible.

can you pls explain this?

Hello, Nathan or Dr. Shane?

Dr. Shane or Nathan. What do you mean: Do not take a sample in a clean/ non problem room? I have people wanting test without evidence of problems is this not advisable?

Also, it just started snowing here. Does that mean do not take an outdoor sample, but do take the indoor samples?

Juan Jimenez wrote:Yep. Thanks! I initially skimmed by it because we don't get much snow here

That could change for you in a couple of days