Should I Get A Mold Inspection When Buying A House? (My Top Tips)

Are you interested in buying a house but concerned about mold?  Are you considering hiring someone to test the house for mold?

You are in the right place. In this guide, I will go over the pros and cons of having the home tested for mold --- and my top tips for doing it correctly.  (Here is my favorite DIY home mold test kit.)

In this guide, I will be going over...

should i get a mold inspection when buying a house
  • how to hire the best company for mold testing
  • tips to verify they do a great job during the mold testing
  • my secret tip on how to verify that mold isn't in the home
  • why hidden water leaks can create mold issues inside the walls

Let's get started with this guide!

What Is A Pre-Purchase Mold Inspection?

A pre-purchase mold inspection is when a professional who is trained to look for mold --- it may be a home inspector, contractor, or technician --- performs such an inspection prior to a home purchase. The mold inspection may be purely a visual inspection of the property for mold, or it may include swabs and air tests that is sent to a laboratory.

The laboratory test results usually includes the estimated spore count per cubic meter of air, as well as the species of mold. As home inspectors, we are not allowed to claim in an inspection report that we discovered mold without sending it to a laboratory for mold detection.

What Are The Benefits Of A Pre-Purchase Mold Inspection?

As a licensed home inspector, I have seen many properties that had hidden mold issues --- where the average person simply wouldn't see it. I have seen mold growing in corners, under stairs, on windows, inside furnaces, in the air ducts, and a variety of other locations. With some states, a seller may not be required to even disclose that the home has or had mold contamination --- check your state disclosure laws!

Some people are also highly sensitive to mold, and may even have an allergic reaction simply by walking into a house. Other people don't react to mold in the same way, and can just live with mold and not be truly affected.

best uv light for hvac

Do Home Inspectors Check For Mold?

Not all home inspectors check for mold --- we are all a bit different --- there isn't a national standard for mold inspecting. There is also an extra cost for inspectors to buy mold detectors in the form of air pumps and lab testing. In my home state, there also is no state licensing for mold inspections or mold detection.

Some home inspectors may report a suspicious substance and say that he saw a possible "organic growth" in the basement. Other home inspectors may offer further services such as swab and air tests --- which will give confirmation of mold.

When I do home inspections, and I noticed a mold-like substance, I tell the buyer, and it is up to them whether they want to proceed with laboratory testing.  The mold inspection cost will be anywhere from $75 to $125 per sample (swab or air) sent to a lab.

What Should I Look For In A Mold Inspector?

Inspecting The HVAC

Most of the time, mold is in the indoor air handler or furnace and on the air vent covers. In my home inspections, I would say about 90% of the time, I find mold in the HVAC system. Of course, this is also the most problematic, because the mold spores can circulated throughout the entire home --- compared to mold growing in an isolated location.

Inspecting The House

It's important to know if the professional will be inspecting the entire house for mold. During my home inspections, I am already thoroughly evaluating the entire home for mold, literally going over every square inch with a flashlight. Most mold professionals (not home inspectors) do not usually inspect an entire home the way a home inspector does --- it will be much more brief.

It's good to know what you're paying for though. Are they just going to take a swab of a suspected mold (that is already located)? Or are they just going to do air tests? 

Of course, it is best if the mold professional visually inspects the entire home for mold --- just know what you're paying for.

Inspecting The Attic

Besides inspecting the entire home for mold, I also highly recommend that the mold professional inspects the attic. I recently did a home inspection where there was mold in the attic, it was growing on a number of wood trusses.

It's not very difficult to visually see that there is mold, it is simply a dark substance growing on the wood framing or it might be a light-colored substance --- basically anything that isn't normal. But, you have to know that sometimes the rafters in the attic are covered in dirt and paint from the construction process.

If mold grows undisturbed on wood framing for a long time, it can cause wood rot and structural damage --- always check the attic for mold before buying a home!

Read Also: Does UV Light Kill Mold? (How Effective?)

mold on wood truss in attic

What Are The Advantages Of Lab Tests For Mold?

Air Testing For Mold

Professionals use fixed volume air pumps to test the air for mold. These mold detectors  have a hose attached, and a container connected at the end. Inside the container is a glass slide that collected the mold spores.

When this "container" is sent to the lab, they crack it open, and carefully pull out the slide.  Then, they put the slide under a microscope, and count the number of mold spores --- as well as identify the mold species. Using a specialized mathematical formula, they estimate the amount of mold spores per cubic meter of air.

It's important that the interior air of the home and the outdoor air is tested. This allows an "apples to apples" comparison of the interior air. For example, if the interior air is 3x higher than the outdoor air in regards to quantity of mold spores --- then one can safely say that there is a mold problem in the home. But if the interior air is about the same as the outdoor air, then it would be considered normal.

Remember, there will always be a certain amount of mold spores in the air --- mold spores are naturally present everywhere. This is why mold suddenly starts growing on old bread in your kitchen. Of course, some molds are more toxic than others.

Besides the professional sampling method with a fixed volume air pump, you can also buy home test kits that use petri dishes. The idea is to place the petri dish in different locations of the home, and if mold is growing on it, then you know that there is a mold problem. 

mold inside of furnace

Read Also:  Signs of Black Mold in Air Vents? (An Inspector’s Guide)

How Is Mold Substance Confirmed?

If there is visible mold somewhere in the home, such as on an air vent, then the inspector will have to confirm that it actually is mold. There really is no way to actually confirm that the substance is mold without sending the sample to a laboratory and looking at it under a microscope.

Should I Get A Mold Inspection?

If you have a suspicion that there may be mold in the home, having it thoroughly inspected for mold prior to it's purchase is a wise decision. Besides looking for water leaks, or basements with high moisture --- I also highly recommend checking the air for mold.

Since mold can be hidden behind walls, it is impossible to know 100% for sure that a home doesn't have mold purely with a visual inspection. If you do a few air quality tests in a few different locations in the home, then you can be sure that there isn't a mold issue in the house before you buy it.

Besides air testing, I also recommend that you verify there isn't mold in the HVAC system --- specifically by looking carefully at the air vent covers and inside of the furnace (or interior air handler). Since the HVAC system is the central location of the home's air, if there is a mold problem in the house, it almost always shows up in the HVAC system.

95% of the time when I see a house with a big mold problem, it is because there is extensive mold growth at the indoor air handler. There was mold on the blower fan, the evaporator coil, the furnace housing, wiring, motor etc. It was everywhere!

In my opinion, the mold inspection cost is well worth the money if you are highly sensitive to mold or allergies and have a sneaking suspicion the house may have mold issues.

Read Also: How To Prevent Mold in Air Conditioners (What To Do?)

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Arie Van Tuijl

Arie Van Tuijl

Arie is a licensed home inspector who owns a residential and commercial inspection company in the state of Virginia. He also does specialty testing such as radon gas, termites, air quality, and mold.

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