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Should I Get a Mold Test?

First of all, I'd like to apologize for the above image. It is deeply unpleasant to look at. Now on to the post. Mold tests are one of the most expensive services that you can add on to any home inspection. Should you spend that extra money? Is it going to be worth it?

What does a mold test do?

First, let's talk about what a mold test actually does. There are a variety of mold test types, but the most common is a combination of an air test and a direct physical sample. The air test typically consists of a control test on the exterior and one ore more samples taken within the home. A specialized air pump and spore trap are used to collect mold spores, which are then evaluated by a qualified lab. The lab will extrapolate the data to determine how much mold is in the air in the tested rooms. The direct physical sample can take a few different forms, but the purpose is the same: to provide something to compare the air test to, which allows the lab and/or inspector to make an educated guess about the source of the mold found in the air. Every air sample is going to find mold. Mold is everywhere, so the question is more about whether or not the mold levels are acceptable.

Is mold a problem?

Mold can present a couple of different problems. It has been linked to some health issues, although there is dispute about how much of an impact on health airborne mold can have. For those who have allergies to mold, and especially those with allergies to antibiotics, airborne mold can have adverse effects even with relatively little exposure. While a healthy person may not suffer negative effects, those with lowered immune systems, children, and pets can be susceptible to mold spores. Additionally, mold can damage the materials it grows on. What people call "dry rot" is actually fungal deterioration that can cause structural damage to wood, given enough time. In my experience, significant damage from mold is pretty uncommon without a lot of moisture.

Reasons to NOT get a mold test:

  1. The biggest argument against getting a mold test is the expense. Depending on the situation, it can cost $300 or more for a mold test. The larger the house and the more precision you need, the more the test will cost.

  2. If nobody in the home has any kind of sensitivity to mold, you might not need to do a mold test. I hesitate to recommend against a mold test for this reason, but if you don't have kids, pets, allergies, or a weakened immune system, mold isn't likely to cause a lot of issues for you.

  3. If you are going to gut the home and plan to remediate mold anyway, you don't necessarily need a mold test. If you're already going to do the work, don't worry about spending the extra money on a test.

  4. Finally, if your inspector recommends against getting a mold test, listen to them. I like getting paid more, and I get paid more if you buy a mold test from me. But, believe it or not, I have recommended against people getting mold tests in the past. I'm not sure how often other inspectors are willing to do so, but if we are telling you not to pay us more money, you should listen to us.

Reasons FOR getting a mold test:

  1. One of the biggest reasons to get a mold test is if anyone in your home might have some sensitivity to mold. Remember that this includes allergies to antibiotics based on penicillin. Aside from the expense, there is no harm in checking to make sure that mold levels are normal. Again, remember that every test will come back positive, but we want to know whether there are potentially harmful levels of mold in the air.

  2. If you have a finished basement and there has EVER been any potential water intrusion, it would be a good idea to get a mold test. Mold can grow behind walls or above ceilings where you won't be able to see it, but it might still be able to get into the air. Additionally, if there is carpet in the basement, that increases the likelihood of mold. (P.S. please, please do not put carpet in your basement)

  3. If you have a crawlspace and.... Well, let's just stick with that. If your home is primarily or largely on a crawlspace, in my experience you have about a 99% chance of having mold down there. You will want to know if it is getting into the rest of the home from there. Mold remediation can be expensive, and that is doubly true for remediation in a crawlspace. You want to make sure that any issues down there are staying down there.

  4. If you are purchasing a log home, just go ahead and get a mold test. Given that everything in your log home is edible, as far as mold is concerned, it is always a good idea to make sure that you don't have any fuzzy little problems gnawing away at your structure. I have done many log home inspections, and the two most common invaders that I encounter in them are mold and carpenter bees (see my post about WDI inspections).

  5. If you have been living in your home for a while and are experiencing allergies or respiratory difficulties that you didn't have before, you should consider getting a mold test. You don't have to be purchasing the house for it to make sense. Mold remediation companies often offer some sort of mold test, but it would be better to hire someone who has no interest in selling you thousands of dollars worth of repairs. If I, or most inspectors, perform a test for you, it doesn't make a difference to me whether or not there is a problem. I don't make money off of repairs. If a remediation company does a test, though, there is always the risk that they might inflate the concern because they know they can get a lot more money from the repair than from the test. A home inspector might also be able to direct you to certain cost-effective repairs that could help you avoid spending huge amounts of money on remediation companies.

  6. And, finally, if your inspector recommends that you get a mold test, you should consider listening to them. Hopefully, you have hired a home inspector that you know you can trust (i.e., me). I often offer mold tests for the above reasons and more. If I recommend getting a test, though, it is because I really think you ought to do it. Your inspector has a lot of experience and probably has a good reason to be concerned. As long as you have a trustworthy inspector, you should listen to them.

This article is an incomplete guide to considering mold testing. As always, the best way to determine whether or not you need a test is to ask your home inspector. If you are on the fence about whether or not to do it, ask your inspector during the inspection itself. Just keep in mind that a good mold test is going to require 2-3 business days to get results, since home inspectors don't generally have licensing for evaluating the spores.

Any questions? Give me a call or text at 380-867-3213, or send me an email at

Even if you don't live in Central Ohio, I am always happy to answer questions as much as I can.

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