Mold clearance inspections & testing FAQs.

This article series describes the post remediation mold clearance procedures and testing that should be used after a mold remediation or mold cleanup project.

Post Remediation Mold Clearance Inspection & Testing Questions & Answers

These questions & answers about the basics of mold clearance inspections & tests that should be performed after a costly mold remediation project were posted originally at MOLD CLEARANCE INSPECTIONS - please remember to take a look at that article as it gives an understsanding of the basic concerns involved.

On 2019-04-16 by Anonymous

Thank you!

On 2019-04-16 by (mod) - what samples do you collect for mold remediation clearance, and how?

Anon

I like to see adhesive tape samples of representative surfaces

. Previously moldy, cleaned surfaces

. Settled dust on horizontal surfaces in the work area, where one can find areas missed on occasion

. Settled dust on horizontal surfaces outside the containment as a check for cross contamination

Details of the procedure, an easy one, are

at TAPE & BULK SAMPLING & TESTS for MOLD

On 2019-04-16by Anonymous

I have a question about how to collect dust samples after remediation that includes air scrubbers having been run:

Your suggestion to wait at least 24 hrs before collecting air samples makes a lot of sense as does the recommendation to collect dust samples as well. If the space in question has had mold removed, surfaces cleaned and HEPA vacuumed, and air scrubbers run for a couple of days and then turned off and dust allowed to settle, how do you collect dust samples?

Our mold inspector explained three industry-standard options, but not were really viable because the space will be so clean there won't be any dust to speak of to collect. How do you do it? Do you do tape lifts or what?

On 2019-04-02 by (mod) -

Thank you for the nice comment Anon. We work hard to provide sound information without bias, so I'm really grateful when a reader finds that effort useful.

We also welcome criticism, content suggestions, corrections: working together makes us smarter.

On 2019-04-01 by Anonymous

Thank you. The service your provide here free of charge or hassle is truly incredible. You are a gift to many, many people. Thank you for your expertise, passion, and generosity.

On 2019-04-01 by (mod) -

Normally one doesn't remove moldy wood such as framing or sheathing. Instead it is cleaned and the source of water corrected.

On 2019-03-31 by Anonymous

Thank you. And, yes, of course I understand the limits of assessing via written exchanges on this site.

That said, the area of staining is very small (12" square). There is no visible mold on the surface. If we were to use an invasive test and found mold in the wood, how would you remove that section of wood if the wood is part of the exterior framing of the house?

On 2019-03-31 by (mod) -

I'm sure it's apparent that without a shred of information about your building I can't know where water has gone or whether or not there is a large mod Reservoir in the structure.

Typically more than 30 square feet of contiguous mold is considered large and deserves professional remediation while smaller reservoirs should also be removed but can typically be handled by a homeowner.

On 2019-03-31 by Anonymous

My husband just had a question about this invasive test idea.

Since the areas of concern are extremely limited in size, what would be the point of doing an invasive test since even if there were some mold within the wood, since the wood is an exterior support beam of the house, what could we do about it? I wouldn't want data for the sake of data.

Re-reading your answer, you refer to "a large mold reservoir" but since the staining and water intrusion was very contained, would you think that invasive tests in a case like that are pointless because, as I say, what would you do if there were some mold within the wood given the location of the wood.

I guess it would help to know how you define "large." Thank you, in advance, for clarifying that.

On 2019-03-30 by Anonymous

Thank you very much!

On 2019-03-30 by (mod) - when to stop spending time and trouble to reduce risk

Anon

It's always a tough question to decide when to stop spending time and trouble to reduce risk of a hidden problem.

A large mold reservoir hidden in a wall, floor, or ceiling cavity can ultimately become a health or IAQ concern for building occupants. There is some air movement in and out of building cavities - site dependent.

My general approach is to find the one or few most-suspect areas, investigate one or a few of those invasively. If no trouble is found, that is if there is no problem that needs remediation in the investigated spot, it's reasonable to stop there.

I don't want to send mold investigators running madly through the house with an axe shouting KNOCK it DOWN Like the derby-hatted home inspector in Mr. Blanding Builds His Dream House)

On 2019-03-30 y Anonymous

Thank you so much for your detailed post. It gives me some piece of mind because the preferred protocol you describe is what the mold inspector and the remediation company (not related to each other in any way) are planning.

I do have one additional question, though this might not be the proper page to post it, but here goes:

There are water stains on the sub floor underneath windows. The issue was long ago resolved except for one location, which we have since resolved.

(All related to age of home and technology used when it was built, which has since been upgraded.) My question is this: If there is staining on the sub floor that runs along the floor the width of each window, is about 1" - 3" wide, and does not go through to the underside of the sub-floor.

should we open up an area of wall below each window to check the framing to see if there is any mold on it (or the back of the dry wall and/or baseboard) from when the leaks were active? And if so, what can you do if there is mold of exterior framing?

Also (last question, I promise!), whenever there is staining (such as on the sub-floor or if framing had water stains) should the mold inspector conduct a test to see if there is any mold growth within the wood even if there does not appear to be any on the surface? How far do you hunt for such things and when do you stop?

On 2019-03-29 by (mod) - Use of Air Scrubbers in mold remediation

Thanks for asking an important question Anon

Use of Air Scrubbers in mold remediation

OPINION:

No air scrubber can ever remove an actual mold problem in a building. The physical mold growth or moldy material has to be found and either cleaned or if it's one that can't be cleaned (such as drywall or insulation) it is removed and the exposed remaining surfaces cleaned.

During a mold remediation, negative air machines are used (blowing air out of the building) to reduce air pressure in the work area as part of dust containment to prevent cross-contamination that otherwise could blow mold into other areas of the building.

At the end of all cleaning, because there may be airborne mold remaining, a remediator may like to leave an air scrubber running for 24 hours - though one could probably do as well by thorough fresh air ventilation too.

During that time the remediator may let the air machine recirculate air in the work area (though I'd have kept it blowing outside) to indulge in the fantasy that they can leave the air very low in airborne particles of any kind, thus "passing" a post-remediation inspection and test.

My preferred procedure - which sometimes upset the remediators - was always to have ALL air moving machines OFF for 24 hours before my clearance inspection and test. Then I might collect settled dust samples - I never ever rely ONLY on air tests as the variability is so great that a negative result (nothing found) is not reliable.

My reasoning is that IF there remains a mold reservoir that was not removed, during that 24 hour still period, it may release enough spores that I find them at abnormally high levels during my post remediation inspection and test.

Conversely if the remediator's air-scrubber is running continuously all during that interval before my inspection and test and also during my test I may see a falsely-low level of airborne particles that in truth is going to shoot upwards in the few days after everybody leaves (again only if cleanup was incomplete).

Remember that the remediator is anxious to do whatever she can to be sure her work will "pass".

My opinion is it's least expensive to be sure the job is successful the first time than to have to argue and bicker about a return to do more cleaning later.

So bottom line is you and I agree.

Interstingly there is an opposite situation that can occur too when "air scrubbers" are left circulating (and presumably filtering out airborne particleds_) in the work area at the end of the job.

IF there is a lot of remaining dust, debris, mold that was not removed (that is, sloppy incomplete work) the air movement caused by the scrubber can stir up far more mold than is removed by the scrubber.

Consider that standing in the kitchen waving your vacuum cleaner wand in the air will never be able to suck up and remove a cloud of dust bunnies who are cowering under the couch in the living room two rooms away.

In other words if a problem source remains, scrubbing air won't remove it but in some cases the stirring up of air might actually make things look worse than still air conditions would present.

This sort of snarl-up is why blind "air tests" or what you call "spore traps" done without more inspection and thought are simply not reliable.

On 2019-03-29 by Anonymous

If "air scrubbers" are the last step in a detailed remediation approach, how long should we wait before having the mold inspector "test." The follow up for clearance testing does NOT rely on test results alone and is a multi-pronged approach that is focused on visual inspection.

However, since testing is impacted by so many variables, including having air scrubbers running for a day or two as the last phase of the remediation plan, my thought is that immediately mold spore trap tests would necessarily collect less spores than if the space were allowed to settle and return to some sort of baseline. (I consider air scrubbing something that would affect the baseline spore count, at least in the short term). I hope this makes sense. Thank you, in advance, for your response.

On 2018-06-15 by Mold Removal Express

Very helpful post. Thanks for sharing.

...

Continue reading at MOLD CLEARANCE INSPECTIONS - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• ACCURACY OF AIR TESTS for MOLD
• AIR MOVEMENT in BUILDINGS
• MOLD ACTION GUIDE
• MOLD CLEANUP COMPANIES
• MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
• MOLD CLEARANCE: FOLLOWUP STEPS
• MOLD CLEARANCE INSPECTIONS
  • MOLD CLEARANCE PROCEDURES when, where, and how a post mold remediation job inspection and test should be performed
  • MOLD CLEARANCE TIMING
  • ACCEPTABLE MOLD LEVEL
  • MOLD CLEANUP, VISUAL CHARACTERISTICS
  • MOLD LEVELS IN BUILDINGS
  • MOLD CLEARANCE: FOLLOWUP STEPS
  • MOLD CLEARANCE TEST, SUCCESSFUL
• MOLD / ENVIRONMENTAL EXPERT, HIRE ?
• MOLD INFORMATION CENTER - starting point for building mold contamination problems
• MOLD INSPECTORS & MOLD TESTERS
• MOLD PREVENTION GUIDE
• MOLD RESISTANT CONSTRUCTION
• WHEN TO STOP LOOKING FOR MOLD

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