Mold on Walls, Drywall, or "Sheetrock"
Causes of mold growth indoors
How to Find & Test for Mold on Walls

DRYWALL MOLD - How to sample mold on drywall or Sheetrock® surfaces; where to look, where to collect mold samples
MOLD CULTURE TEST KIT VALIDITY - separate article
SWAB & PCR SAMPLING & TESTS for MOLD - separate article
TAPE & BULK SAMPLING & TESTS for MOLD - separate article
VACUUM CASSETTE FILTER SAMPLE TESTS for DUST / MOLD - separate article
Questions & Answers about mold growth on building drywall surfaces and about mold testing procedures
References

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Guide to testing mold on building drywall: This article describes proper procedures for sampling mold on drywall in buildings. Because moldy drywall or "sheetrock" is often the consequence of a building flood or wet floor, the moisture gradient in drywall varies at different heights above the floor surface. Because different mold genera/species vary in their hydrophilic nature (some molds love water more than others), different mold genera/species are likely to be found at different heights on a building wall. Which molds are most important to sample?

This document describes how to find mold and test for mold in buildings, including how and where to collect mold samples using adhesive tape - an easy, inexpensive, low-tech but very effective mold testing method. This procedure helps identify the presence of or locate the probable sources of mold reservoirs in buildings, and helps decide which of these need more invasive, exhaustive inspection and testing.

How to Test or Sample Building Drywall, Gypsum Board, "Sheetrock" and other Building Surfaces for Mold Using Clear Adhesive Tape

This article discusses:

Why & where mold grows on drywall: how much moisture, water, or leakage is necessary for mold to grow on drywall - mold growth below leaky skylights & windows
Moldy drywall sampling mistakes to avoid; proper use of a flashlight finds "hidden" mold on drywall
What mold looks like in different areas or on different surfaces of drywall
Why are different mold genera/species found at different heights on building walls? We illustrate how three tape at three nearby locations on drywall can collect three completely different mold genera/species
How should mold test samples be collected from building surfaces?

As I've explained in various articles and at our instructions for collecting and mailing a tape sample to our lab, different mold genera/species will be found growing on the same or nearby sections of drywall on a building surface, depending on several variables.

If the largest contiguous mold area in a building is trivial in amount, say 1 sq .ft., we would not test it unless we thought that the mold we see is representative of a larger mold problem I cannot see. Small areas of mold should simply be removed.

For larger areas of mold (certainly if more than 30 sq .ft. of area is moldy or if mold is growing on many surfaces in a building), you are looking for the dominant species present and particularly allergenic or toxic species present in the environment.

The photo at page top shows several colors of mold on a drywall surface. Still more mold may be present but still lighter in color and harder to see. Each of these may be a different mold genera or species. Which molds that we see on a building surface should be sampled? We explain the answers here. At Wall test cuts to spot hidden mold we discuss finding mold on the wall cavity side of drywall. Also see MOLD RESISTANT DRYWALL for a discussion of that product type as well as a list of drywall or gypsum board industry standards and drywall product MSDS sheets.

This article is part of our 'how to' photo and text primer on finding and testing for mold in buildings using simple clear adhesive tape on suspect or visibly moldy surfaces. Also see MOLD GROWTH ON SURFACES, PHOTOS and MOLD APPEARANCE - WHAT MOLD LOOKS LIKE.

How to Decide Where to Sample for Mold and How Many Mold Samples To Collect

Collect one mold tape sample per location; do not use the same tape to sample from multiple locations.

Choose a representative sample spot: select a representative spot of mold growth on a surface such as a wall, cabinet, ceiling or floor.

This means that if you see what appears to be a single coating of mold-suspect growth on a surface, all rather consistent by color, texture, and what it's growing-on, you need only one sample of that material. Variations in appearance or texture or growth surface or mold growing in different building areas or floors are reasons to sample more than one thing.

In our photo (above left) of severe indoor mold contamination in a home, many different mold genera/species were present on the drywall (sample by color or texture) as well as still other genera/species that varied by growth surface, type of wood, painted surfaces, other materials.

Color: Sample molds of different colors: black, white, green, red, gray, brown, yellow, pink - are often (not always) different species.
Texture: Sample molds of different textures: hard lumpy big grainy versus fuzzy and easily blowing into the air - are often (not always) different species.
Growth Surface: Sample molds growing on different building materials. This is quite important. Completely different mold genera and species may be found growing in the same building on different growth substrates: drywall room side, drywall cavity side, plywood sheathing, wood stud or joist framing, painted surfaces, exposed fiberglass insulation kraft paper vapor barrier - are often (not always) different species. Even on the same growth surface (drywall for example) different mold species appear at different locations according to variations in moisture level - explained just below)
Building area: basement, crawl space, living area, and attic all have different moisture conditions, often different building materials, different patterns of air movement and exposure. The "green mold" found on wood subflooring visible overhead from inspection in the basement is very often a completely different genera and species from the "green mold" found on the roof sheathing in the attic of the same building.
Representative dust samples: we will sometimes screen areas where there is no visible mold by collecting settled dust particles from a horizontal surface. If you are going to collect a single dust screening sample, collect it either from the area of which you are most suspicious (a flooding basement), or from the area where building occupants spend the most time (perhaps a bedroom or family room).

Variations in moisture gradient in the drywall - so if a floor was flooded, water-loving molds grow closest to the floor (such as highly-visible black molds like Stachybotrys chartarum), while molds liking the drywall to be a little less wet grow a little higher (such as Cladosporium sp., Cladosporium sphaerospermum, Cladosporium cladosporioides, Ulocladium chartarum), and molds liking the drywall to be still less wet grow higher still on a vertical wall (such as Aspergillus sp., Aspergillus glaucus, Aspergillus flavus, Penicillium sp., etc.). Therefore where the tape sample is collected can make a big difference in what you find.

Photograph: Moldy drywall supports different mold genera and species at different moisture levels in the same area - Daniel Friedman

In the first photo of moldy drywall, three completely different mold genera and species were within a few inches of one another at different heights on this laundry room wall.

This condition often occurs, but the different genera may be as close as inter-mixed and even overlapping in the same area, to growing several feet apart on the same wall, to growing in the same building but on different materials on different surfaces.

In this case, tape sample #1, the bottom mold, was Stachybotrys chartarum, tape sample #2, the middle mold, was Cladosporium sphaerospermum, and the top tape sample, #3, was Aspergillus flavus. Of these three, the Aspergillus is the easily-airborne toxic spore which is more likely to be a problem in the building if it is present in sufficient quantity.

How to Prepare & Save Mold Tape Samples for Mailing to a Mold Test Laboratory

Photograph: Multiple tape samples on one zip-lok bag - Daniel Friedman

In this photo detail you'll see that using a new and clean zip-lok™ bag, we placed several surface tape samples on the same bag. If you can't assure that the bag surface is clean between tape sampling, use a new bag for each sample.

Interruptions in the moisture gradient absorption path: for example at a wet floor which soaks the bottom of drywall, moisture wicks up into the drywall material. But moisture wicking may be reduced suddenly at a horizontal drywall joint, resulting in easily-visible borders or lines in fungal growth.
Exact pathway of water on a surface or in a building cavity: so tracing the exact water path through a ceiling or wall cavity is very important.

Are you collecting too many mold test samples?

There are nearly always multiple mold species present in any environment where mold producing conditions are present.

We sample surfaces likely to host different molds, focusing on surfaces which appear to represent mold or mold-suspect material growing over large areas in the building. Don't collect and send 50 samples. If you find you want to collect a great many samples it would probably be smarter and more economical to bring in an expert to survey the building and who can sample more strategically.

Interrupted Mold Growth Pattern on Building Drywall - Why Does Mold Growth Sometimes Stop in Straight Lines?

Mold growth pattern on drywall (C) Daniel Friedman

In our photographs shown above the thick black mold growth on drywall in a wet basement appears to nearly "stop" in a neat horizontal line just about four feet from the floor surface. Why?

Stachybotrys chartarum, which dominated the mold on this drywall, really likes wet conditions. As we explained above, the genera/species of mold growth may vary on a surface of the same material as a function of variation in moisture levels in the material.

In our photo at above right we show by having made a test cut into the moldy drywall that mold growth stopped its rapid advance up the drywall when it encountered the horizontal tape joint between the lower and upper runs of drywall in the building. We have found two common explanations for this observation:

The moisture wicking upwards in drywall from a wet floor is interrupted where the paper-covered edges of two horizontal runs of drywall abut.
Mold growth on joint compound alone is often significantly less in a building than on paper-covered drywall in the same area. This observation describes the success in "paperless drywall" sold for some applications.

Frequently Asked Questions (FAQs) about mold growth on drywall in buildings

Question: What are the necessary conditions for mold growth on building drywall and in the wall cavity?

Mold formation on drywall and wallpaper below leaky window (c) D Friedman

I had energy efficient windows installed in my townhouse over a year ago. This past spring one of the master bedroom windows leaked after a rain storm because the caulking failed. The company immediately came out and recaulked the window and it hasn't leaked since.

Mold growth in wall cavity below a leaky window

[Photo at left provided by InspectAPedia, taken from a New Jersey home and not the building discussed by this reader, shows mold growth on drywall and on wallpaper beneath a leaky window. A single rainstorm combined with the window having been left partly opened caused this mold growth.

After checking the basement ceiling cavity below this window as well as in the wall cavity itself, our investigation found that the total moldy area was less than 30 sq.ft. and the mold cleanup could be handled as a normal renovation job. More examples of mold growth on and in wall cavities and hidden by wallpaper are shown at MOLD GROWTH ON SURFACES, PHOTOS - Ed.]

My concern is that I now have a water stain under the window on the drywall, and since I have a mold allergy, I'm wondering if there might be mold on the inside of the drywall. I read your article on testing the dry wall but as mentioned in the article would rather not cut into it unless it's necessary. I looked at other articles but didn't see one with a picture resembling the water stain I'm concerned about. What would you recommend?

By the way, this is a very helpful website. I was considering using ozone for any possible mold in my place but see from your article that's not a good idea.

Continued: I emailed you recently about the possibility of mold forming on the inside of drywall under a window that leaked last spring when it rained.

I contacted a bonded company about replacing the drywall. The gentleman I spoke on the phone with told me that he's attended mold seminars and that mold requires an ongoing source of water or moisture over an extended period of time to grow. In his opinion, since my leak occurred only once during a rain storm that lasted an hour or so, there's little or no chance mold could grow on the inside of the drywall under the window. He also said that since the water stain is barely visible, this is more reason to conclude there's no mold on the inside of the dry wall.

I thought it would be a good idea to check this on your website, but didn't find any topic that seemed related to the conditions for mold formation, so I thought I should email you. Is what he says about mold formation accurate? And if so, is it reasonable to conclude that there's probably no mold on the inside of the dry wall under the window that leaked?

I'm hoping he's right, because I won't have to replace the drywall. I'll replace it if necessary, though.

Thanks again for your help. G.N.

Reply: Even a single event water leak is likely to lead to mold growth in building ceiling or wall cavities - it depends on ...

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with mold, hidden mold, and with tracking down just how much water leaked into the building and where it went.

First, how disappointing that your new windows leaked - certainly a wet wall below a leaky window is not particularly energy efficient, and indeed it could become a mold reservoir.

The risk of a mold problem that you can't see but that is significant enough to merit removal is not something I nor anyone should guess at by email nor by telephone (that is, with no building inspection) with so little information. MOLD EXPERT, WHEN TO HIRE provides advice on deciding (or not) to hire someone to inspect and test for mold contamination.

Watch out: mold testing alone, without a building inspection, case history, and occupant interview, is not reliable.

I would not rely on "mold tests" - a test, especially an air test for airborne mold, performed without an expert diagnostic inspection of the building is just not reliable in cases where the result is "negative".

Continued reply: G., your bonded company expert is mistaken, as you can see in our example photo above showing mold growth in the wall cavity and behind wallpaper below a window following a single event leak.

A single water entry event can cause mold growth in a building cavity, on the wall cavity side of drywall, in the wall insulation, on the kraft paper insulation facing, on the building structural wall wood studs or cavity side of the exterior wall sheathing.

Your expert would, however, be correct, if s/he asserted that the extent or size or severity of mold growth from a single event leak depends on the size of the leak, the amount of water entering the cavity, where it went, what materials got wet, and the moisture exit rate from the building cavity.

Unlike your expert, beyond that advice I'm reluctant to promise what is or is not in a building cavity on a building I've not studied. Often an expert on site finds evidence of chronic leaks that a normal building owner may never have noticed. Very often very small leaks or wet spots do not produce a significant problem mold reservoir.

Why even a single building leak can cause significant mold growth in 24-48 hours

But because building wall or ceiling cavities dry out very slowly, leaks into a wall or ceiling, even from a single event, can initiate problem mold growth in those areas. In general, if a building interior or building cavity interior contains mold friendly organic materials such as wood, paper, drywall, fabrics, drywall, mold growth can be expected to occur if the area remains wet for 24-48 hours. Low temperatures can sometimes slow down mold growth so a building that was wet during freezing weather may have a bit more time.

What happens to mold in a building wall or ceiling cavity once the area has dried out?

When the building cavity finally has dried, several conditions are likely to occur:

Depending on the mold genera species, there may be a very large spore release as the fungus dries. For example I've seen an enormous release of Aspergillus sp. spores during building dryout procedures preliminary to a large scale mold remediation project. And depending on the amount of air communication between the building cavity and the occupied space, this mold reservoir and spore release can be a problem for some occupants.
Once the building cavity is sufficiently dry ("sufficiently" depends on the mold genera species and the material on which its colony has formed) the mold colony or reservoir may become dormant - that is, it may stop further expanding growth and it may stop releasing spores to the environment.
Future changes in the building condition, ranging from increases in indoor relative humidity to new leaks into or near the same moldy drywall or moldy building cavity can cause a renewal of mold growth and spore release activity at a more rapid rate and on a larger scale than would have otherwise occurred if the pre-existing mold reservoir had not been present or if it had been previously removed and the building cavity properly cleaned (and of course had the cause of building leakage been repaired).

How do we decide if destructive or invasive inspection of building cavities is justified

In general, if there has been anything but the most absolutely trivial leakage into a building wall or ceiling cavity, and if thus we decide to investigate, I recommend choosing the one or two most suspect leak areas, where there is the most evidence or suspicion of the area that received the most water or was the most wet. In those areas I'll make a small test cut, perhaps 2" x 4" into the ceiling or wall, through the drywall. There we perform a visual inspection for visible mold on all surfaces and materials; if there is insulation present we also collect a vacuum sample of that material, and we collect tape samples of any visible mold on any of the newly exposed surfaces.

If that most-suspect area is "clean" of any strong suggestion of mold contamination, we don't cut or dig further without some other compelling reason to do so.

What is appropriate when there has been building leakage and where there is a concern for possibly significant hidden mold contamination is to make a decision about whether hiring an expert is justified in a particular case - see MOLD EXPERT, WHEN TO HIRE for advice on making that decision.

More photographs and examples of mold growth on drywall are found at Mold on Drywall or Sheetrock®. Also see HIDDEN MOLD, HOW TO FIND.

Question: why is this black mold growing on these drywall ceilings & walls?

I attached three mould photos for you. Can you help me to find out the possible reasons? - L.Y. 6/4/2013

Reply: Summary of common reasons for mold growth on drywall

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem. That said, here are some things to consider:

Possible reasons for indoor mold growth ?

In all cases of indoor mold growth the mold needs food (wood, paper, organic material), oxygen, and water; some molds thrive on light, some are tolerant or intolerant of UV, and other factors.

Moisture, water, leaks, condensationa are key determinants in indoor mold growth

Of all of these, water is the key necessary ingredient which we can track and which is inviolate - that is, no water, no moisture = no problem mold growth.

I have no context for the photos, no age, no building history, occupancy, use, or other key information that an onsite inspection would disclose.

But I note that your middle photo looks as if it is a ceiling and because there is a vent therein I suspect this may be over a bathroom; Common moisture sources for such an area might include

leaks into the ceiling above
high indoor moisture from in-building sources such as a steamy shower or clothes dryer
leaks from the ducting for the ceiling fan

The density of mold growth in your photos suggests that there have been leaks from above. But in some cases even without actual water leaks into a ceiling or wall we can see dense mold growth on building drywall caused by other wet building conditions (flooding of the floor for example, or a heating or steam pipe leak).

Mold growth tracking ceiling or wall framing

The fact that the mold seems to track or be more dense along lines resembling either drywall joints or actual locations of framing would argue for either leaks from above penetrating at drywall butt joint seams or quite often, temperature differences (wood framing in contact with drywall produces cooler temperature than insulated ceiling cavities).

Temperature variations can in turn invite higher levels of condensation on cooler surfaces in those areas. We also see this effect in THERMAL TRACKING & THERMAL BRIDGING

So even when we don't see leak stains showing a water source, the mold growth pattern might track moisture gradient in the materials and thus suggest something about its cause.

You will need to remove the moldy drywall in any case, as well as any insulation that has been wet or exposed to mold.

That will let you inspect the wall or ceiling cavity for leaks as well as to check that the bath vent fan is actually venting and is properly used.

Reader Follow-Up:

But how to explain the reasons for this photo? It is the most black area (I showed in previous email）when my landlord removed the ceilling, there has plastic.

`Actually I know very little knowledge about mould. My landlord said the mould was caused by the lack of heat. Can you show me some ideas?

Does the water stain of the second picture show water leakage? This house is more than 40 years old.

There is no indoor ventitaltion system, the fan in the bathroom has been blocked for long time and the fan had not been insulated well.

There's no fan to transfer gas to outside in the kitchen. - Y. 6/5/2013

Reply:

Mold is is not directly caused by lack of heat - cooler temperatures in fact retard mold growth, if all other conditions are equal. But lack of heat that leads to condensation problems or to a frozen burst pipe and leak can indeed cause or encourage indoor mold growth.

And I would agree that heating a building, as it dries a building, would avoid problem mold growth provided that there are not leaks or abnormal moisture sources.

If there is mold there is a condensation or leak problem to find and fix. If the mold is on the wall cavity side of the plastic then there are leaks into the wall cavity - either water leaks or air leaks, perhaps combined with incomplete or improper insulation. I'd have to see more detail to have a more confident opinion. From your photo I'm not even sure what's ceiling and what's wall.

Some speculative examples of what could be going on include:

water leaks in to the plastic-covered cavity
moist air leaks into the plastic-covered cavity from either side of the wall, ceiling or whatever we're looking at

The suggestions I made earlier about tracking down leak and moisture sources should, perhaps in this case, be combined with inspection for air leaks into the cavity from indoors or from outside.

...

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol

"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests

Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens," Patricia Donald, Department of Plant Microbiology and Pathology, Lewis Jett
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
"Management of Powdery Mildew, Leveillula taurica, in Greenhouse Peppers," Ministry of Agriculture and Lands, British Columbia - Original source: www.agf.gov.bc.ca/cropprot/peppermildew.htm
Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Fiberglass: Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Fungi, Identifying Filamentous, A Clinical Laboratory Handbook, Guy St-Germain, Richard Summerbell, Star Publishing, 1996, ISBN 0-89863-177-7 (English) (buy at Amazon)
US EPA: Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
Mycology, Fundamentals of Diagnostic, Fran Fisher, Norma B. Cook, W.B. Saunders Co. 1998, ISBN 0-7216-5006-6 (buy this book at Amazon)
US EPA: Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

Environmental Health & Investigation Bibliography - our technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
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