Mold clearance inspections & testing: Here we explain and describe the post remediation mold clearance procedures and testing that should be used after a mold remediation or mold cleanup project.

Guide to Post Remediation Mold Clearance Inspection & Testing

This article is part of our series: the Mold MOLD CONTAMINATION ACTION GUIDE which provides an easy to understand step-by-step guide for dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold "mildew," moisture, in your house or office, building-related illness, involving your physician, treatment, sick building investigators, reduction of irritants, and special products to help clean buildings and air.

Our advice on inspecting and testing to evaluate the adequacy of a mold cleanup job is divided into the articles listed at the top of this page.

We include photos of successful and somewhat questionable mold cleanup practices throughout these articles. Our mold cleanup jobsite photo at left shows a thorough inside demolition, surface cleaning, and spot-application of fungicidal sealant in a 1940's panelized home that had suffered from a severe mold contamination problem while left unattended.

Also see MOLD INSPECTORS & MOLD TESTERS for our online directory of mold inspection and testing experts.

See MOLD CLEANUP COMPANIES for our online directory of mold cleanup companies - mold remediators.

To avoid a conflict of interest we recommend that mold inspection, testing, or post-cleanup inspection and testing should be performed by an expert who has absolutely no financial or business relationship with the mold cleanup or mold remediation company. Before hiring us or any onsite test or investigation expert for a field investigation, inspection, or testing, be sure to

review MOLD / ENVIRONMENTAL EXPERT, HIRE ?.

For each step in the process of diagnosing, identifying, removing, and preventing indoor mold problems in buildings, links to in-depth articles are provided. In some cases in this document We use excerpts from longer dissertations on these subjects.

Where we do that we offer a link to the longer, more detailed original documents as well. Extensive, in-depth articles about mold and other indoor air quality concerns are organized at

our MOLD INFORMATION CENTER

This article series discusses the importance of mold clearance inspection and testing following a mold cleanup or "mold remediation" project and gives advice on who should conduct mold clearance sampling, when clearance testing should be performed, and how to interpret the results of a post remediation mold clearance inspection and test. What should be involved in a mold remediation clearance inspection and test?

What is the Purpose of a Post Remediation Mold Clearance Inspection?

The purpose of a mold clearance inspection is to assure that the mold cleanup has been done correctly and effectively in the work area and to confirm that the cleanup did not accidentally distribute high levels of moldy dust and debris into other building areas or into its mechanical systems such as heating or air conditioning systems.

Watch out: To avoid conflicts of interest, mold clearance testing should never be performed by the mold remediation contractor nor by someone with any business or financial connection with such contractors.

Also, just "testing" a building for mold is not nearly as reliable as an expert visual inspection.

And if you are testing for mold after a mold remediation job, don't forget to test for cross-contamination of moldy dust by screening building areas that were not part of the mold cleanup job.

Can We Rely on Air Tests for Mold after a Mold Cleanup Job? No.

Simple air tests for mold after a mold remediation job may be quite unreliable as the airborne level of particles varies enormously from moment to moment, especially depending on variables in building conditions such as we list below.

An air test captures a small volume of air at a moment in time and should not be used as the sole criteria for passing or failing a mold clearance inspection and test. Here are some of the sources in variability in the level of indoor particles in air:

• HVAC systems turned on or off
• Fans moving air or not
  
  See AIR MOVEMENT in BUILDINGS
• People in the buildings or not
• Level of human activity: we can measure the difference in airborne particle stir-up among an empty room, a room with a person sitting working at a desk, people walking across a carpet, and kids jumping on a bed
• Windows open or shut
• Doors open or shut between rooms and to the outdoors
• Operation of air scrubbers, kitchen and bath powered or passive air exhaust vents, and passive building ventilation system
• Building temperatures vs. outdoor temperatures and changes in the degree of stack-effect-generated air movement upwards through the building
• The level of building cleanliness, degree of removal of dust, particle reservoirs, or particle reservoir disturbance such as moving building insulation
• The use of other building cleaning equipment such as vacuum cleaners, floor polishers
• See details at ACCURACY OF AIR TESTS for MOLD

And the commonly-stated and simple use of a mold remediation clearance test acceptable mold spore ratio (percentage of indoor versus outdoor spore counts) can be very unreliable too. A visual inspection for extent of work, cleanliness, and careful selection of screening samples of mold from surfaces, dust, and possibly air, inside and outside the work area are what's needed in a mold remediation clearance test if you want to trust the results.

A Summary of How to Conduct Mold Remediation Cleanup Project Follow-up Clearance Inspection & Testing

A mold cleanup or mold remediation project clearance inspection is performed to determine if the demolition and cleaning appear to be complete and effective, and to assure that there has not been accidental contamination of other building areas. Clearance inspection and testing should be performed after all demolition and cleaning, and before the containment system has been removed.

Failure to respect this criterion risks cross-contamination between the remediation area and other building areas.

Mold Inspection Clearance should include visual inspection of the building for active leaks or remaining wet areas, visual cleanliness of both areas that were remediated and other building areas which are at risk of cross-contamination.

Clearance sampling typically includes one outside air baseline sample and four inside samples using surface dust collection as well as air and/or vacuum samples both to establish the success of cleaning of the remediation area and to check for evidence that cross-contamination of non-remediation areas occurred. Depending on the size and complexity of the building, more than these five samples may be required.

Clearance inspecting, sampling, and testing should be performed by a party who is has no affiliation with the remediation contractor. At your request We can re-inspect the building following demolition and cleanup to confirm that the target areas have been successfully cleaned and that other building areas have not become contaminated during the process.[See Note 1 below]

I have attached my detailed Lab Determination Report along with information about growth factors and health hazards of molds. More information is at my public information website www.InspectAPedia.com, my mold information testing website at /sickhouse.htm and at your health department.

Any mold clean up project must be safe and effective in both its procedure and in its end result. In severe or costly mold cleanup cases the procedure should be documented (work receipts, photos and notes). This information will be helpful in avoiding a health risk to future occupants and in reducing liability for owners.

Note [1] Clearance testing performed after all remediation, repair, and cleanup are “complete” checks for presence of significant levels of toxic spores in the interior air or in dust found on building surfaces.

A history of prolonged or major water intrusion or the presence of significant levels of moldy material in a building suggests this follow-up step to reduce the chance that other hidden mold remains in the building, or that remediation and cleanup were not properly performed.

We do not recommend “home test kits” offered by some vendors as they are fundamentally flawed in methodology. For additional investigation, for example in areas where there was no visible mold but where odors persist, call to make arrangements which might involve limited destructive measures such as making inspection openings to permit visual, surface, and air sampling

CLEARANCE PROCEDURES: to be Used After a Mold Cleanup / Remediation Project

See CLEARANCE PROCEDURES for detailed recommendations about the procedure to follow to assure that a mold cleanup project has been successful and that other building areas have not been either cross-contaminated during the mold cleanup, or that they do not have another independent mold contamination problem.

There are no single accepted "pass-fail" criteria for clearance inspections. I examine remediated areas for mold or other allergens and We look in other building areas for evidence of spread of contaminated demolition debris or inadequate cleaning if cleaning was recommended for those areas.

My evaluation combines a visual inspection of the extent of removal and cleaning of infected materials/areas with a microscopic examination of surface, dust, air, and/or vacuum samples collected at the property.

Visual Inspection for Demolition & Cleaning Completeness

A visual inspection is performed of both the cleaned area and other building areas.

In the clean-up area we want to know that demolition has been sufficient - that no moldy materials remain, and that all surfaces appear to have been physically cleaned. If a fungicidal sealant was to be applied, we want to see that it was not simply sprayed atop mold and dirt or debris instead of first cleaning those surfaces.

Mold Screening Tests for Effective Cleaning in the Work Area

We will collect mold clearance inspection test samples of physical surfaces which appear to still be moldy or dirty; if all surfaces are clean we will collect at least one settled dust sample from a representative cleaned surface in each major area. We may also collect other screening samples by using air or vacuum sampling methods. But beware; air sampling alone is not a reliable means of screening a building for problems.

Mold Screening Tests for Cross Contamination Outside of the Work Area

Outside of the remediation area we will collect screening samples of suspect surfaces, settled dust, vacuum and/or air samples of representative areas in the building, paying special attention to areas (or equipment such as HVAC systems) which are at particular risk of having been cross-contaminated by inadequate dust containment measures during the cleanup.

General Property Condition

We will also report ongoing conditions which continue to put the building at extra risk of a new mold problem, such as failure to correct various causes of leaks, water entry, and high moisture.

Lab Processing of Test Samples

Test samples from the site examined in our laboratory using appropriate chemical/stain preparations and a light microscope at magnifications up to 1000X. Our opinion regarding the level of cleanliness reflected by fungal samples is based on several existing studies of building contamination, a comparison with the original contamination levels, and our field and laboratory experience examining properties before and after remediation.

ACCEPTABLE MOLD LEVEL What are Acceptable Mold Levels in buildings

For details see  ACCEPTABLE MOLD LEVEL for details about acceptable levels of mold in buildings before or after a mold cleanup project.

Problems with indoor versus outdoor spore counts

Comparing indoor mold spore levels with outdoor mold spore levels

A common mold remediation clearance test plan specifies that the indoor mold level or spore counts should be no more than 50% of the outdoor level. This approach can generate nonsense, particularly in mold sampling reports I've reviewed in which the genera and species of the indoor mold spores were completely different from the outdoor mold spores. For example an outdoor "Pen/Asp" spore count of 1000 spores/M³ of air might be compared with an indoor "Pen/Asp" spore count of 500 spores/M³ of air.

But often the outdoor "Penicillium/Aspergillus" spores are not the same species as the indoor species, making such count comparisons completely meaningless.

Worse, some labs include small basidiospores in their "Pen/Asp" count since often many small amerospores (small round featureless mold spores) like certain Penicillium spores and certain Basidiomycetes are difficult or even impossible to differentiate microscopically. If the indoor and outdoor Penicillium or "Pen/Asp" spores are different species from one another, you are evaluating the effectiveness of a mold remediation project by comparing "apples and oranges."

Examine the indoor mold genera and species

It is important therefore to look qualitatively as well as quantitatively at indoor mold spores after a mold remediation project.

If there is a high level of indoor spores of the same genera (and species) as the problem-mold which was originally identified then the cleanup may have been incomplete, regardless of "outdoor spore count comparisons.

A common example of incomplete work in which we find problem-levels of Penicillium or Aspergillus after a mold remediation is when mold-infected fiberglass insulation has not been removed because it "looked clean" to the naked eye of the mold cleanup crew.

A simple vacuum sample of that material can indicate whether or not the insulation needs to be removed.

What indoor mold levels indicate a problem?

After a mold remediation? It depends partly on site conditions. In a sealed room where moldy debris has been removed, testing immediately may disclose an abnormally high level of indoor problem mold which has remained airborne even though the cleaning has removed all of the original mold reservoir. In that case some additional surface cleaning and fresh air exchange may be all that's needed.

Mold counts versus mold Species: Even more questionable is the use of "generic" airborne mold spore counts without further attention to genera and species.

A count of 200 Stachybotrys chartarum mold spores/M³ of air would be unusually high as this mold is not normally airborne. I'd be worried about where those spores came from. Conversely, a count of 200 Aspergillus sp. spores/M³ of air in the same circumstances might be considered very "clean".

What indoor mold spore level is considered "contaminated" then depends in part on what mold genera or genera and species have been identified. But if the indoor mold spore count/M3 of air is high enough, we may decide that more investigation or cleaning is needed regardless.

While there is no well-established quantitative standard for fungal spores on surfaces or in air, mold contamination is considered present in a building when the total mold spore concentration per cubic meter of air is above 10,000. (Baxter, ETS).

Acceptable levels for individual species vary since species toxicity varies widely as does spore size, weight, and other features which affect risk to building occupants. E.g. Aspergillus/Penicillium in a "clean" residential building study was at a mean of 230, in buildings known to have a moisture or flooding problem it was at 2235 and in mold contaminated buildings the figure was 36,037.

Mold sample processing lab variation

Some writers also warn that mold labs have reliability problems. We agree that two experts counting the same slide will not provide precisely the same counts.

Our lab participates in a "round robin" quality assurance program in which a group of expert mold sample processing labs around the country "count" spores on the very same slide (we mail it around). We compare our count results as a method for checking on and refining our procedures.

While counts vary among labs, it is unusual for counts by expert labs following the same (agreed-on) count procedures to vary by as much as one order of magnitude.

If the mold sample processing lab is actually using an expert to process the samples (rather high-volume part-time minimally-educated workers), then the variability in lab results is very much less than the variation in mold sample results caused by variations in sampling conditions We discussed below at "Mold Sampling Conditions Cause Wide Variation in Results".

Surface samples of mold:

the presence of toxic or allergenic mold as a dominant particle in any sample (surface or air) is usually a cause for further investigation or remediation. The presence of incidental occurrences of toxic or allergenic material in surface samples requires interpretation in light of other building conditions, type of particle (spore chains), and other factors.

Cultures of mold for Clearance Testing

Since only a small percentage of all molds (perhaps 10%) will grow in any culture at all under any condition, using a culture to screen for problematic mold is a questionable practice. There are uses for mold cultures but We question their application for building screening.

The mold level target is never zero except in special applications such as medical and drug facilities which operate in a "clean room" environment where no stray particles are permitted. Mold is a natural ingredient in outdoor air most of the time. We do not want to find higher indoor mold levels than outdoor, and we do not want to find high levels of problematic mold spores indoors.

Mold Sampling Conditions Cause Wide Variation in Mold Test Results

Warning: interpret all quantitative mold clearance test data with caution, particularly air samples. Individual samples of airborne mold (or any other airborne particles in a building) show tremendous variation from minute to minute, usually by many orders of magnitude, making "ok" mold clearance sampling test results a thing to view with care.

If the mold remediation clearance investigator did not document the sampling method, including where, when, and under what conditions a sample was collected, interpretation of sample results can be tenuous.

Were building fans on or off? Were windows open or shut? Was work going on in the area? How long after completion of the mold remediation project did the investigator wait before testing?

Turning on a ceiling fan in a room can increase the airborne particle level by a factor of 1000! In situations of particular risk (such as sensitive occupants) or ambiguously-conducted post mold remediation testing, additional or periodic testing should be considered.

VISUAL CHARACTERISTICS of Successful Mold Remediation Sites

Please see MOLD CLEANUP, VISUAL CHARACTERISTICS for details about the requirements for visual inspection of a building after a mold remediation project.

All suspect or mold-contaminated material, which cannot be cleaned, should have been removed. There should no demolition debris left in the building. Areas of removal such as remaining structural components, floors, and other surfaces should have been thoroughly cleaned, HEPA (High-efficiency particulate air filtering system) vacuumed, wiped, and sealed if a sealant was to be used. HEPA vacuuming is important since ordinary "shop vacuums" and most home vacuum cleaners will simply pass small mold spores right through the system, actually increasing the level of airborne mold.

Remediated areas should be free of visible mold. On previously infected structural members or surfaces, some remediators use fungicidal sealants as extra assurance against movement of remaining incidental spores and to reduce potential future moisture uptake in wood and thus future mold growth. We report the extent of such treatments if evidence of such is visible.

The most common mold cleanup mistakes

We encounter are failure to maintain a working dust containment system for the cleanup area during the procedure, failure to actually clean up demolition dust and debris from every surface, and bringing in new building materials or actually beginning reconstruction of the building before a successful clearance inspection and test have been completed.

This last "error" means that either the clearance inspection and test are limited in assuring the success of the job or that some of the new work has to be removed to permit inspection and testing.

SUCCESSFUL MOLD TEST: How do We Define Successful Post-remediation Mold Test Laboratory Results

See MOLD CLEARANCE TEST, SUCCESSFUL for details about what constitutes a successful mold test result after a mold remediation project.

In the living area we should find in surface, dust, air, or other samples no more than incidental occurrence of the problem mold or allergens previously found at the property. There should be no significant presence of toxic or allergenic spores or other allergens indicating a remaining mold reservoir.

Air tests, while not a reliable overall indicator of building condition, should, if used for mold screening, show indoor mold levels at or below typical outdoor levels or at levels associated with various studies of "clean" buildings.

Warning: some investigators risk making erroneous conclusions if they attempt to compare directly levels or counts of indoor Penicillium/Aspergillus spore levels with outdoor Penicillium/Aspergillus spore levels in air samples. With some exceptions, it is almost impossible to determine the species of these genera in an air sample.

A previous report on a property we were asked to investigate showed that the indoor Penicillium/Aspergillus spore level was equal to the outdoor level and that both were at 8000 spores/M³ of air. But a detailed investigation of the samples disclosed that the outdoor spore level was in fact a species of Penicillium while the indoor species was Aspergillus niger which, at this level

We considered an indicator of incomplete cleaning traced, ultimately to incomplete demolition. In this case the original "count comparison" of indoor to outdoor Penicillium/Aspergillus spores was like comparing apples and oranges. It was nonsense.

AFTER THE MOLD CLEANUP: Addressing Other Leaky or Moldy Building Areas

See MOLD CLEARANCE: FOLLOWUP STEPS for detailed advice about important steps to take after a mold cleanup project has been completed.

Some building owners make the mistake of insisting that only limited areas of a moldy building be addressed, or they do not repair other building leaks.

When leak-damage, mold, or suspect areas remain in a building following a mold related remediation, the insurance company, contractors, and inspector could express confidence only in the specific areas treated and only at the single point in time of the final successful clearance inspection.

The building remains at risk of future discovery of a separate pre-existing or new mold or water damage problem caused by new moisture or leak problems and potentially exacerbated by mold inoculation from pre-existing un-remediated areas.

Research on Mold Clearance Inspections

• ANSI Standard & Institute of Inspection Certification (2008). S520 Standard and Reference Guide for Professional Mold Remediation. Website: https://webstore.ansi.org/ Provided to ANSI by the Institute of Inspection, Cleaning and Restoration Certification [IICRC], cited below. Web: https://iicrc.org/
• Institute of Inspection Cleaning and Restoration Certification. S520 Standard and Reference Guide for Professional Mold Remediation. Vancouver WA: IICRC 2003
• Light, Ed, J. Bailey, and R. Gay. NEW PROTOCOL FOR THE ASSESSMENT AND REMEDIATION OF INDOOR MOLD GROWTH [PDF] In Proceedings of 12th International Conference of Indoor Air Quality and Climate, vol. 1, pp. 163-168. 2011.
  Summary:
  The effectiveness of current response procedures for addressing mold growth is evaluated, and the authors recommend a new protocol for building assessment and remediation. Assessment based primarily on mold testing has significant limitations and may fail to identify sites with mold growth.
  
  Microbiological testing is replaced by engineering evaluation with a focus on site moisture dynamics.
  
  Critical performance objectives for remediation are to restore the site to conditions preceding water damage while preventing occupant exposure to airborne mold generated by the repair process. Hazardous material abatement procedures are generally not needed for mold remediation.
• Parrott, Kathleen R. MOLD REMEDIATION [PDF] (2009) Virginia Tech Cooperative Extension, Virginia State University, retrieved 2022/-6/-5 original source: https://vtechworks.lib.vt.edu/bitstream/handle/10919/50207/2901-7021.pdf?sequence=1
  Excerpt:
  Do I Need to Test for Mold?
  If you can see mold or smell the distinctive musty odor of mold, you have mold. If you have water problems in your home that have caused building materials to become wet for extended periods of time, you probably have mold. Testing for mold will most likely not tell you anything you do not already know – you have mold, and it needs to be remediated.
• Robinson, Christine. THE ASSOCIATIONS BETWEEN MOLD REMEDIATION PRACTICES AND POST-REMEDIATION VERIFICATION TESTING FOR RESIDENTIAL STRUCTURES IN SOUTHERN CALIFORNIA FROM 2008 TO 2019 [PDF] PhD diss., Trident University International, 2020. - This graduate work has been published as open access.
  Excerpt:
  The purpose of this study was to determine the correlations between how closely water damage mitigation and mold remediation work follows consensus guidelines and the results of Indoor Environmental Professional assessments, especially mold spores.
• Schaible, Ronald D. THE ROLE OF THE INDOOR ENVIRONMENTAL PROFESSIONAL IN MOLD REMEDIATION [PDF] In ASSE Professional Development Conference and Exposition. OnePetro, 2005. - retrived 2022/06/05 original source: https://www.jurispro.com/files/articles/Schaible-asse.pdf
  Excerpts:
  
  The IICRC (2003) states that "The role of an IEP is to perform an assessment of the fungal ecology of property, systems and contents at the job site, create a sampling strategy, sample the indoor environment, interpret laboratory data and determine Condition 1, 2 and 3 status for the purpose of establishing a scope of work (pre-remediation assessment) and/or when necessary to verify the return to normal fungal ecology."
• Silicato, Steven R. "Mold remediation: a practical approach." Plant Engineering 57, no. 6 (2003): 50-50.
• Texas State Department of Health. 2007. TEXAS MOLD ASSESSMENT AND REMEDIATION RULES [PDF] (2007)Environmental Health Group, Mail Code #1987 Environmental Health Group, Mail Code #1987 Policy, Standards, and Quality Assurance Unit Policy, Standards, and Quality Assurance Unit Division for Regulatory Services Division for Regulatory Services Texas Department of State Health Services Texas Department of State Health Services 1100 West 49th Street Street Austin, Texas 78756 Austin, Texas 78756 512-834-6773 or 1 6773 or 1 6773 or 1-800-293-0753 extension 3600 0753 extension 3600 0753 extension 3600 www.dshs.state.tx.us/mold www.dshs.state.tx.us/mold
  Note:
  For questions regarding mold licensing mold licensing mold licensing in Texas, please contact: the Texas Environmental and Sanitation Licensing Group, (512) 834-6610 or (800) 572-5548 Fax: (512) 834-6614
  Excerpt:
  This subchapter contains requirements for the licensing and registration of persons performing mold assessments and mold remediation, requirements for the accreditation of mold training providers, minimum work standards for the conduct of mold assessments and remediation by licensed and registered persons, a code of ethics, and penalties.
• Tiffany, J., Bader, H., and Pratt, A. “Industrial Hygiene and Clearance Considerations for a Microbial Remediation Project”. Bioaerosols, Fungi, And Mycotoxins: Health Effects, Assessments, Prevention, And Control. Albany, NY: Fungal Research Group 2001 523-528.
• WME, MOLD CLEAN-UP PROJECTS POST-REMEDIATION CRITERIA ARE CRUCIAL TO SUCCESS [PDF] (2004) Wonder Makers Environmental, PO Box 50209, Kalamazoo, MI 49005 USA, Tel: 888-382-4154 Web: www.wondermakers.com - retrieved 2022/06/05 original source: https://www.wondermakers.com/Portals/0/docs/Mold%20Clean-up%20Projects.IS.pdf
  Excerpt:
  As concerns about mold contamination indoors become more prevalent, the need for standards within the industry grows at an increasingly rapid pace. Not only is it crucial to have mold remediation standards, but post-remediation standards, as well.
  
  Non-standardized postremediation inspections cause a number of problems, including project failure, confusion for the contractor, increased liability for the whole industry, limited comparisons between projects, and a breakdown in the public's confidence.
  
  Although the post-remediation evaluation process includes many parts, including sample collection and analysis procedures, this article focuses on the importance of logical and effective post-remediation sample interpretation from a macro approach.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-01-05 - by (mod) -

I mean beyond the containment area in the nearest part of the building. The point is to make sure that the containment was successful - that we didn't track or blow moldy dust out of the work area.

I was phone-dictating.

I meant to say that IMO a better, though non-quantitative, way to screen a building for contamination is to collect a representative sample of settled dust.
See

DUST SAMPLING PROCEDURE https://inspectapedia.com/sickhouse/Dust_Sampling_Guide.php

If there is a significant level of mold in such a sample then we figure more cleaning is needed.

On 2020-01-04 by Anonymous

Thank you, Dan. Since this will be happening next week, would like to clarify: Since we will have double containment set up, when you say testing "outside" of the containment area, do you mean beyond any contained area and set up testing equipment somewhere in the room, at large (that's not part of containment and has no mold issues).

And what does "Justin settle dust" mean? Thanks so much!

On 2020-01-04 by (mod) - Clearance testing question:

From your description I'm not sure what testing inside such a tiny containment area would be useful. A visual inspection of the work area and the area outside of the containment is critical. If you want to do testing Justin settle dust from outside the containment area

On 2019-12-28 by Anonymous - Clearance testing question:

Thank you, Dan. Sorry for being too vague.

Let me describe what is to be the containment area more specifically as you have sparked my concern w/your comment about the area being so small as to be on the margin of professional standards.

We have a small entryway at our front door (about 6'across and 5' deep).

iling in the entryway is vaulted so it’s extremely tall. Above the door there’s an 18” tall transom window and above the window is another 18" of wall.

Above the wall is a ledge that extends toward the front of the house (not into the room) that's about 2' deep and above that is an arch window that looks like a dormer window from the outside. (I have a photo, but don’t want to post it here. If there’s a way to email you, I can do that.)

A few months ago we discovered a leak under the dormer window which is a very hard place to monitor because it's so high. What we saw was a stain on the OSB board/ledge that ran along the bottom of the window a couple of feet across and about 6” in. The moisture meter did not go off along the all Only the OSB board appeared wet. (We later learned that because of how the dormer was wrapped, it blocked the ability of the meter to perceive moisture.)

We contacted our mold inspector and a remediation company was called in. A small area of containment was set up on the ledge w/a way for the remediator to reach his arms in. He cut a small square of drywall beneath the window on the side where the ledge was most wet. Inside was very wet and mold could be seen. He closed it up, sealed it off, and we set out to develop a plan.

Central to the plan was to have our siding guy identify the source of the leak(s) and do repairs, which he did, though could not test it right away because we had to wait for caulk to dry. Everything was dry and looked good around the window. The only areas where there were problems were along the bottom of the window, on one side in particular.

We're are now on the cusp of remediating the area to clean it, though will test with water from hose first once containment is set up to make sure the siding guy fixed all the leak(s) which seemed to stem from an area just beneath the arch window. Since his repairs, we’ve been monitoring the window w/a hydrometer set up on the ledge inside the small contained area, that we can read remotely. It’s not ideal, but better than nothing (maybe). Since the repair, the readings have been within normal range.

The remediation company plans to set up containment that will seal off the entire entryway, top to bottom, side to side, for the duration of the project. This will give the crew space to work. They will access the space through the front door. A zipper will be on the containment inside, but no one is to use it unless there is an emergency.

The plan is to remove the OSB board on the ledge and dry wall under the window to access the extend of damage, remove wet/moldy materials, clean, etc, (HEPA vacuum twice, w/machine located outside the front door because there’s a resident in the house who cannot tolerate the noise and who is unable to leave the house during the work period), use fungicide where needed, run HEPA for a period of time after work is complete, etc). The remediation company owner and our mold inspector will be on site to supervise and problem-solve as the work progresses.

When finished, the plan is to wait 24 hrs after the HEPA vacuum has been turned off, at which point the mold inspector will conduct a thorough visual inspection and do testing, w/testing only as a supplement to her visual inspection. But since testing is a component, we're trying to figure out how she can get into the space w/o compromising the air she samples.

Given that the problem area is so small it seems a bit much to contain more than the entryway, but you seem to be suggesting the area is too small to be professional (for lack of a better word). I'm not sure if this clarification changes your perspective or if you still suggest a larger containment area and if so, why.

Sorry for how long this is. I couldn’t figure out how to get all the info more clearly and completely to you so that you to render your opinion which I highly value.

On 2019-12-28 - by (mod) - I would never rely on an air test alone as a mold clearance inspection.

I don't have a clear understanding of exactly the layout and situation, though I know that the total size of love area is so small as to be on the very margin of what justifies a professional remediation job

. I would never rely on an air test alone as a mold clearance inspection. What's much more important is a thorough visual inspection to be sure that the extent of work was correct and complete.

On 2019-12-28 by Anonymous - Clearance testing question:

Clearance testing question: Leak at bottom of dormer window above front door in our entryway. The window sits out from a ledge about 2 feet deep. There will be double containment: small area on ledge extending up along window and larger area that will stretch from the floor of the small entryway up to the ceiling so mold remediation techs can get in with their ladder and be able to work on the ledge and off the ledge, as needed, as they remove, clean, etc.

Since the contained area is relatively small (footprint will be about 6’ x 5’) there will be a challenge for the mold inspector when it’s time to do clearance testing (inspection and sampling 24 hrs post remediation) because accessing such a small space will necessarily change the air inside in a relatively significant way due to the small size of the area.

Do you have any ideas as to how best to do this to increase the chances of getting a representative sample that hasn’t been too compromised by the exchange of air inside the containment and air outside of it?

On 2019-11-07 by (mod) - How equipment do i test the air testing with

Honestly LB I don't think it makes sense for someone without training to pretend to test a building air quality; even if the equipment or sampler or sample collector is mechanically easy to operate, the samples that you send to a lab may be absolutely meaningless if they are collected without enough understanding of the building, building history, leaks, damage, air movement, type of hazard for which the building is being screened, etc.

I would prefer to start by a clear statement of what problem is being addressed.

On 2019-10-22 by Ibfrenovations

How equipment do i test the air testing with

On 2019-04-25 by Anonymous

Just finished remediation. Mold inspector conducted careful supervision of the process and thorough visual inspections.

Waited 24 hrs for air scrubbers to be off before taking air and tape lift samples. Just got the lab results back and things look good except two locations still show asp/pen, albeit very low numbers (10 and 4, respectively). It’s my impression that asp/pen is an indoor kind of mold and if all mold reservoirs were identified and remediation was complete, there should be no asp/pen showing up on a lab report. Can you please comment on this?

On 2019-04-16 by Anonymous

RE-posting without his 50 carriage returns

Anonymous said:
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?

Moderator Replied:

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

...

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