“Will we need mold cleanup?” Few homeowners haven’t come across a dubious substance in their home and wondered this at one time or another. 

Mold can be a concerning issue in homes, causing health problems and structural damage if left unchecked. However, not everything that looks like mold is actually mold.

In this blog post, we’ll share instances where things may appear moldy but aren’t, and some insightful stories from the field.

The Misidentified Mold Story

I was called in a few weeks back to do a “second opinion” mold inspection in the wake of another upper peninsula home inspection company which shall remain unnamed. 

Fortunately, the homeowner sensed something amiss. Before spending gobs of money on a mold cleanup company to come in and tell them they didn’t have a problem, they called me in for a second mold inspection. What I found was a case study in the concept of “all that’s fuzzy isn’t mold.”

The individual in question had mistakenly identified numerous items as mold without proper testing equipment. This inspector charged full price for a visual-only inspection—and declared nearly everything he found to be mold. This included boxes that had dust on them from travel, haze on polyurethane wood finish (which happens when you have high humidity), and even efflorescence, which is a very commonly occurring salt residue that forms on concrete walls due to moisture wicking from the ground. 

Are you wondering if you need mold cleanup? Before investing in a mold test, here are a few common things that look like mold but aren’t. Go through this checklist first. It may eliminate your worry – and your need to spend big bucks on mold cleanup. 

5+ Common Household Mold Lookalikes…That Won’t Require Mold Cleanup

1. Efflorescence

Efflorescence on a concrete floor. It’s easy to see how it could be mistaken for mold!

Efflorescence is often mistaken for mold due to its white appearance on surfaces. This white substance is caused by salts in concrete and can accumulate when moisture is present. While it may look like mold, it’s not a fungal growth. 

You can often find efflorescence on concrete floors and walls, especially in the basement. It’s also common on brick or block exteriors.  No mold cleanup necessary! (But if you find it unsightly, the Concrete Network has an excellent article on efflorescence prevention and removal.) 

Zinc Oxide Buildup on Polyurethane Varnish

Zinc is a mineral used to create a satin or matte finish in polyurethane varnishes. Under certain conditions, the zinc can separate out and create a white haze on the surface, which is sometimes mistaken for mold. (You can read about zinc haze prevention and removal here.) 

Concrete on Wood 

A footer wall form made of lumber. In older homes these boards would often be re-used as floor joists, with bits of concrete still clinging to them.

Another common misconception involves concrete on wood. Contractors often use wood forms for concrete. If not cleaned properly, these forms may appear moldy. 

Concrete residue can look uncannily like mold. However, it’s essential to distinguish between actual mold and residual concrete debris. 

Telling the difference can sometimes be tricky. In crawl spaces, inspectors might come across a white fungus known as Cladosporium. It can be really hard to tell the difference between Cladosporium mold and concrete. However I have found a simple way to instantly differentiate between them: In my crawler robot camera, Cladosporium appears bleach white and smooth when compared to concrete, which is gray. Score one for home inspection technology! 

An experienced mold inspector should be able to tell if it’s something requiring mold cleanup or just concrete residue even in a visual inspection. But proper mold testing equipment and testing (see below) will let you know for sure if you are looking at a mold cleanup job or not. 

Algae on Roofs

I get a lot of calls from people who think there is mold on their roof. However it is very rare for a roof to require mold cleanup. Dark stains on shingles may resemble mold, but they are often algae. 

A product called “Forget” can be used to remove algae stains, but it won’t work on mold. If you think you have mold on your roof, I’d highly recommend purchasing a bottle of Forget first. If the Forget doesn’t work, you may need mold cleanup. If it does, your problem is gone. How’s that for a low-cost mold test? 

Coal Dust

In the U.P., we have a lot of older homes that used to burn coal. It’s very common to find coal dust during an Upper Peninsula home inspection, especially in basements. In some homes the coal dust can be found throughout the home as it can get blown up into the walls. 

People often assume the coal dust is black mold. But it’s not – and if you know what you’re looking for it’s pretty easy to distinguish the two. 

Other Mold Look-Alikes: 

Other substances, such as dirt, various substances such as paint splattered on the walls, or soap scum in bathrooms, can be mistaken for mold. 

It’s essential to differentiate between these substances and actual mold. An experienced home inspector should be able to put your mind at rest – or at least tell you what kind of mold you are dealing with so you can approach mold cleanup in a way that makes sense for your situation. 

Preventing Mold Growth 

It is so much easier to prevent mold growth in the first place than to have to deal with mold cleanup. 

To prevent mold growth in humid environments, experts recommend using borate, which can be absorbed by wood and serves as a preventative measure against mold. Dehumidifiers in basements can also help control moisture levels.

Understanding Mold Testing Equipment 

No legitimate professional mold inspector would think of doing a mold inspection without proper equipment. 

At UP Home Inspection, we primarily do canister testing. We run 25l of air through a canister using a specially designed pump that’s made for doing mold testing. We have a couple different varieties. The one I use most often I calibrate myself so I can set it to the same standard every time.This method is approved by all major home inspection certification organizations for household mold testing. 

Inside that canister is a little piece of film that catches particles as the air comes through. Anything that’s in the air is going to stick to that plate before it goes out the back side of the canister. 

In addition to testing the air for mold spores and/or particulate, we also do a visual inspection. We go through the house and look for visual evidence of mold – which also includes ruling out anything that for sure isn’t mold. If we find anything we think might be mold, we do a tape swab to sample the area. 

Once we send the canisters and samples to the lab, they take that film and put it into a machine that reads what’s there and tells us what sort of spores and/or particulates we are dealing with. 

We can read mold, fungal spores, dander, fiberglass fibers, all kinds of stuff they pull off that film. We offer a couple different levels of mold testing depending on your needs. The basic level just tests for mold. If you want a more comprehensive air quality test, we can add in the particulate testing. 

Identifying Moisture Sources

A moisture detector is a handy tool to have on a mold inspection!

The other thing a good mold inspector can do for you during a mold inspections is to help you identify the source of moisture that is promoting mold growth. Addressing the moisture issue is as important as identifying and removing mold.

For example, say we find mold on a pool table. A lot of people think that getting rid of the pool table or cleaning it will solve the problem. Unfortunately mold cleanup isn’t that simple. Where’s that moisture coming from and how can it be mitigated? 

The biggest problem with mold is the humidity. And it can be tricky. I’ve seen mold in attics that are 120 degrees. You’d think it wouldn’t be able to survive there because it’s so hot. But the reality is, mold can go dormant. As soon as it cools down and gets humid again, it takes off because the spores aren’t damaged. So in a situation like that I look at roof penetrations or any place the moisture can be intruding, because that’s going to be the root cause of the mold issue. 

Do You Really Need Mold Cleanup? 

While mold can be a serious issue, it’s essential to differentiate between actual mold and substances that may look similar. Understanding the differences can save homeowners from unnecessary panic and expenses.

At U.P. Home Inspection, we use specialized equipment and knowledge to accurately identify and address mold problems while also pinpointing the source of moisture so you can get rid of the problem for good. 

If you are wondering whether mold cleanup is in your future, let us put your mind at rest. Schedule a mold inspection with us today!