Teach Yourself Environmental Home Inspecting
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  NOTE: May Dooley passed away in March 2024. This site will remain available as a tribute to her.

Mold Inspecting Overview

Tools needed for mold inspecting:

Setting the stage:

"Mold is everywhere," so why get excited about mold? Yes, mold spores are everywhere. Good housekeeping continually removes mold particulates along with house dust. However, from a health standpoint, our concerns relate to mold growth.

Why is mold growth important? Because as mold grows, it makes spores which can float off into the air (as long there is a pathway for that), and it gives off gases, which also penetrate into room air. Both these can affect our health. There are other components of mold growth, too, which will be addressed later, specifically, microparticles and mycotoxins.

But first, let’s keep it simple:

The ABCs of dealing with mold

A. Find the mold growth;

B. Safely remove the mold growth, without spreading it to clean areas or harming anyone’s health due to exposure;

C. Keep the mold from coming back;

D. Safely clean up the work area;

E. Test to confirm the area is successfully remediated and may be re-occupied.

F. Reduce clutter, have a quality HEPA vacuum cleaner, possibly a quality HEPA room air purifier, follow good housekeeping practices, including an in-depth fall and spring cleaning.

G. (Central air conditioning systems will be addressed later.)

Food and Water

Mold needs what we need to survive: food and water. To find mold growth, search where the food and water are, such as:



Follow the path of the water to find the mold, both visible and hidden.

Why bother with mold that is in wall or ceiling cavities?

We remediate hidden mold, because the molds that typically grow in these cavity areas don’t require continued moisture to keep growing.

There is no inexpensive, sensitive test for mold gases. Even the more costly tests cannot tell you where the growth is. Save your money. The trick is to find and eliminate the sources, and then the gas production stops.

Use a moisture meter to find hidden moisture.

If there is, or was, water intrusion in an area with nutrient value for mold, that’s a place to look for mold growth. Like night follows day.

Moisture meters are effective but not guarantees of being able to reach the moisture. For example, perhaps the plywood sheathing in a wall cavity is wet but not the wall. You can only sample at the wall.

Mold growth may also be present in areas that formerly were wet but at present test dry.


If you see discolorations that may be mold growth, try one of the following for a clue:

If you can, hold a flashlight on the surface parallel with the discoloration. Often mold fuzz is easier to see this way.

Use clear tape to touch the discoloration. Hold the tape up to the light. If you see a film, it’s probably mold. If there is nothing on the tape, it may be a stain. This isn’t definitive but gives a clue.

Caution: Touch the smallest area at the periphery of the suspected mold, and hold that up to the light. Getting a square inch of mold on the tape is not necessary and may expose you unnecessarily to mold particulates.

Do not disturb mold without wearing a P100 or N95 respirator. Exposures to some types of mold can cause allergic and/or inflammatory responses. Sometimes the immune system is overwhelmed, and, if a species is present that can grow in human tissue, a fungal infection could start in sinus or lung tissue.

And what if you find elevated moisture?

-- Ask yourself the question, "Well, why wouldn't hidden mold be growing there? Is there food and water?"

-- You may have just found an area needing remediation.

If there is a leak, how would you prevent mold damage?

The key to avoiding mold growth is to remove wet materials before mold can grow.

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Before going on with more surface testing, let’s stop a minute and talk about Health Effects related to mold exposure. After that, we’ll progress to Testing Options for various aspects of mold testing. That section will circle us around to Tape Testing Instructions, where we pick up on the discussion above.

Or, go back to the Mold Topic Index.

This page was last updated:
August 12, 2020 6PM UTC     
Created: July 8, 2020
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Website by May Dooley     
may _at_ createyourhealthyhome.com  
   Phone: 717-273-1231
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