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ATTORNEYS and EXPERT WITNESSES
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CAR MOLD CONTAMINATION
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VENTILATION in BUILDINGS
How to inspect a building for important but hidden toxic, allergenic, or otherwise harmful mold contamination. This article begins our series of instructions on how to track down the source of hidden mold contamination in buildings. We include hidden mold investigation techniques and we provide procedural suggestions to avoid creating an unsafe condition or moldy mess during the mold investigation process. The fact that mold is "hidden" in buildings does not mean one cannot find it. We look by context: where do we see leak stains, or where do we see building practices most likely to have produced a hidden leak or moisture problem? Ice dam leaks in walls, hidden plumbing leaks, roof spillage by the foundation, are all common clues that often track to a wet building wall or ceiling cavity and from there to a hidden mold problem which may need to be addressed.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
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.
In the photo at page top we see the results of a wall cut through drywall to expose wet moldy insulation, mold on the cavity side of drywall, and surprise! a leak in a pipe that the owner did not know was in her basement wall. However there was good evidence in the form of stains on the exposed side of this drywall. Look at the tan stain which is in the photo in the half-round shape directly above the wall cutout.
Don't try to investigate a building by dashing about with an axe cutting holes willy-nilly. That is an unnecessarily and inappropriately destructive approach to studying a property. But when building history, occupant complaints, or direct site observation of site and building conditions raise the level of probability of an important hidden leak or other damage, directed exploration, often with very modest means, can be very productive.
This article provides a Photo Guide to Finding Hidden Mold in Buildings, but first a mold safety warning about looking for hidden mold.
See TRAPPED MOLD BETWEEN WOOD SURFACES for a discussion of the question of need to remove mold from mated building surfaces.
Also see FIND MOLD in BUILDINGS, HOW TO and see MOLD GROWTH on SURFACES for an index of what mold genera/species are frequently found on various building surfaces and materials, and see Mold Related Illness: Index of Symptoms and finally, for an atlas of building molds and for more microphotographs of building mold samples observed in our laboratory, see Mold Atlas of Indoor Clinical Mold, Pathogens, Allergens & Other Indoor Particles. And MOLD BY MICROSCOPE shows what mold looks like under the microscope.
Making a small 4-inch test cut, using a borescope or a hole saw to look into building cavities, behind trim, or behind wallpaper, even pulling up a few inches of carpeting won't release a tremendous amount of toxic or allergenic mold into a building, and such openings can also be re-sealed or taped pending further investigation or cleaning.
But wholesale demolition, knocking down walls, removing wall to wall carpets, removing building insulation, or peeling back larger areas of wallpaper could indeed be unsafe if it exposes a large mold reservoir. Here is a warning from the US EPA on peeling back wallpaper or other hidden mold exploration methods:
Investigating hidden mold problems
Where to look for hidden mold on and under carpeting and flooring
How to Make Small Test Cuts to Check for Hidden Mold in Building Walls & Ceilings - Using a Drywall Knife
When to Make Larger Wall Test Cuts to Check for Hidden Mold in Buildings
How to Make (or not make) Random Test Cuts to Check for Mold in Building Cavities
Random wall test openings: We have little confidence in and are reluctant to simply make random test cuts in buildings. Since water can take peculiar paths through hidden openings, such as wall plate holes drilled for pipes or electrical wiring or between single pairs of studs or ceiling or floor joists, cutting a hole that does not reveal a problem is no assurance at all that no hidden mold problems exist.
When to Make Strip Cuts to Look for Hidden Mold in Building Ceilings or Walls
When there is an ongoing building complaint that makes us suspect hidden leaks or mold, if we strongly suspect a hidden mold problem but have not found its precise location, on occasion it is justified to make a "strip cut" across multiple wall studs or ceiling joists, exposing multiple wall cavities.
How, Where, & Why to Peel Back Wallpaper to Check for Hidden Mold in Buildings
Photo Guide to Finding Hidden Mold on Furniture, Bathroom Vanities, & Built-In Drawers or Shelving
Photo Guide to Finding Mold Under or Behind Bathroom Vanity Cabinets
What makes a lot of sense sense is to study the building carefully to decide on the building points at most risk of having been wet from leaks due to construction details or other site observations. That's where one would make a test cut.
We frequently add text and photos to this series of articles. (See "What MOld Looks Like" and "Stuff that is Not Mold"links listed at Related Topics ). Readers should also review Mold in Fiberglass Insulation in Buildings at our The Mold Information Center - What to Do About Mold in Buildings
Small amounts of mold can be removed simply by cleaning or removing infected materials, something most homeowners can handle -- but see the Warning Notice at the end of this article. Some mold species can make you sick.
The mold shown in the photograph above is plain to see during construction, but will be covered and hidden completely when the contractor installs the ceiling drywall.
One of our clients discovered this mold during a renovation and was quite concerned that a major toxic black mold reservoir had been found in the building. The client was facing a very costly mold cleanup project if this mold had to be addressed as a toxic material. Luckily this was not the case in this instance, as was easily demonstrated both by a simple inexpensive lab test and confirmed by onsite inspection of other framing details discussed at "Cosmetic Molds" linked-below.
So sometimes the mold in your house might be only a cosmetic concern. "Bluestain" or Ceratocystis/Ophistoma is common on framing lumber and we often find it in attics on the under side of roof sheathing. Unless it's in finished portions of living space where it creates a cosmetic problem, no particular action needed to address this black mold.
Detailed advice about how to determine by visual inspection alone whether or not you're probably looking at one of these common framing lumber cosmetic molds is at our Photo Guide to Cosmetic Molds.
Frequently Asked Questions (FAQs) about Finding Hidden Mold in Buildings
Question: I have a hidden mold problem but none of my "mold inspectors" has been able to find it. How should I proceed?
I am convinced I have a "hidden mold" problem in one of my bathrooms, and have had this problem for quite some time. At times I have smelled a moldy odor, and almost always when I enter the room I IMMEDIATELY experience allergy symptoms.
I have made a visual inspection of the surfaces in the room, and see no mold deposits. I also had a chance to look at the under flooring (the plywood base layer for the floor) a couple of years ago, including the area right adjacent to the toilet bowl, when I had the old tile removed and new tile installed. There didn't appear to be any significant mold signs there.
I also had a handyman cut out two 24" square panels of drywall directly underneath the pipes of both sinks in this room, and although we couldn't see much further than the immediate areas, there were no signs of mold on the inside of the drywall or surrounding areas.
I am affected seriously in terms of health by this problem, and am very concerned about finally finding some way to pinpoint this problem, so I can have it resolved. (I can't afford to completely rip apart the room....walls, floors, ceilings...to find this problem, and further, my residence is a condo, with neighbors underneath and on one side on the same floor, so drastic measures would be difficult to take).
I have had two or three so-called "mold inspectors" out over the last few years, and none was effective. They tried to sell me "mold testing," but to me, this will do no good because
I already KNOW I have mold...the problem is, to FIND it, so I can have it removed. Any suggestions, and any local referrals you can make for services in my area (Arlington Heights, IL, a suburb northwest of Chicago), will be much appreciated. - M.R.
Reply: Be sure that the mold inspection is sufficiently broad in scope, identify risk targets for further investigation, don't rely on "mold tests" alone, and hire an expert who actually inspects
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem. It is possible that the inspectors who looked in the past lacked experience or care, or that their inspection scope was too limited. Certainly if you smell mold it would be a surprise for none to be present. And I agree that a "mold test" without an expert inspection is of little value and that it would fail to provide what's needed: a problem diagnosis and a start to an action plan.
Profile the Building's Leak or Moisture History to Track Down Hidden Mold
If you haven't seen it take a look at HIDDEN MOLD, HOW TO FIND and the articles listed immediately under that heading (article links are at Related Topics ). One of those articles, Use a Flashlight to Find Mold adds another dimension, careful use of light to see hard-to-spot light colored molds.
In the case you describe, where you are already sure that there is a mold problem somewhere but it remains hidden, and where someone has already looked in the obvious places, including modest invasive inspecting by cutting openings at nearby plumbing, my suggestion is to perform a thorough, complete building inspection identifying by observation of construction details, building and site visual clues, building age, history, construction materials and similar approaches, all of the places that present a notable risk of a history of leaks or moisture traps.
Moisture Clues Help Track Down Hidden Mold
Moisture is a gating factor in problem mold growth. That inspection should result in selecting the top few highest-risk locations for further investigation, invasive cutting of limited openings included, if needed.
Smell Testing can Help Track Down Hidden Mold
I'd combine that approach with a careful sniff test or smell test (SMELL PATCH TEST to Track Down Odors) to see if you can track mold smell to mold risk points. More about pinpointing odor or smell sources in buildings begins at ODORS, Smells, Gases in Buildings-Diagnosis & Cure
We can't know from the data at hand so far whether or not the mold problem in your building is small or if professional cleaning will be needed. That will be part of the discovery process.
Strategic Dust Sampling to Track Down Hidden Mold
As a part of a thorough mold investigation, I'd collect settled dust samples from suspect areas and from a few interesting areas on each building floor as a screening procedure. We might find evidence of nearby active mold growth (such as Pen/Asp spores found in chains) as well finding that some building areas are more moldy than others.
Movement of Mold Spores & Gases in Buildings Confound Hidden Mold Investigations
Keep in mind that because ultra-small mold spores as well as odors move through buildings like a gas, you may be smelling or detecting mold in areas that are not always immediately adjacent to the actual problem source.
Hire a Mold Investigator who Actually Investigates
About hiring a mold investigator, we list a variety of building inspection professionals beginning at the EXPERTS DIRECTORY (at page top). And near the top of that article you'll find lists of directories of other specialists including mold and environmental inspectors. Before hiring another inspector discuss your case and your concerns with the inspector and ask him/her to describe their procedure.
If you find that the "mold expert" is simply someone who is going to collect a few test samples and send them to a mold test lab, I'd look further for someone who will be more thorough and who has more experience and expertise. A more useful mold investigation includes taking a careful client complaint history, building age and materials and leak/moisture history, a very thorough outside and inside inspection for risk points, and strategic testing.
Variability in Human Response to Hidden Mold Reservoirs may Confound Mold Investigators
At MOLD STANDARDS we provide a survey of mold exposure standards from around the world. You'll see that all of them set pretty high airborne mold spore levels and that not one of them copes with the enormous variability in individual mold genera/species spore size, allergenicity, pathogenicity, or toxicity.
Finally, by virtue of having my own forensic lab I've been able to perform some interesting tests on individual sensitivity to mold and MVOCs in buildings.
By testing individual clients and buildings in which the clients experienced a severe reaction immediately on entry (such as respiratory distress or allergic response) I found that some people are sensitive to very low levels of airborne mold spores of some genera. For example a woman client reacted within seconds of entry into a building where the airborne mold spore count was dominated by Aspergillus sp. at a level of less than 200 spores/M3 of air, a rather low indoor concentration.
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