If you think you have mold in your home, or you're worried about mold in general, this is a walkthrough of exactly how to test your home for mold, step by step. I filmed it with my friend Ryan Blazer, who inspects homes for mold. We suited up and went to inspect a house that we already knew had mold in it.
Whether you want to test your home yourself or you want to hire an inspector, by the end of this you'll know exactly what you need to do and how to make sure that it's done in the right way. If you're struggling with mold, or someone you know is struggling, being armed with the right information is what lets you approach the situation in the most calm, cool and collected way, with certainty about how to proceed.
Suit Up First
Before anything else comes the gear:
- Tyvek suit: so you don't get any mold spores on your clothes
- Respirator: to protect your lungs
- Goggles: to protect your eyes
The suit matters because of what happens after the inspection. As Ryan explains it, if spores get on your clothes and you jump in the car to drive home, now it's in your car, and then you go into your house, take off your clothes, and now it's in your house.
Take An Outdoor Sample For A Baseline
The outdoor sample is done as a background reading, because you always want a baseline. What have you got floating around outside? You compare that with what's inside, because the inside should be the same or less than what's outside.
So if you have ABC type molds outside, you should see ABC type molds inside. If you see ABC plus XYZ molds, then you know there's a source inside the house that isn't coming from outside.
Take a picture of the location of the outdoor sample and label it.
Step One: The Visual Inspection
The first step is to do a visual inspection, and you're going to need two tools for it.
- A heat mapping tool: it tells you hot spots and cold spots. What you're looking for is cold spots, because if water is leaking and getting into the wall cavity, it's going to cool it down.
- A moisture meter: it has little pins you can stick into the wall or the floor. It tells you temperature and it tells you actual moisture, and it's what you use to verify what the heat map showed you.
Start Around The Outside
- Start around the perimeter of the home. Take a look at the outside to see if there's anything you can visually see that would indicate that that's where the potential source of water is coming from, where the leak is, where there might be the opportunity for water to get into the home. You're looking for cracks.
- Then look on the inside at that spot and see if you can see any kind of signs of water damage or any kind of mold growth.
On this house, one water intrusion point showed up from outside: the grout had separated away from the wood, so every time it rains, water is going to be getting into that crack. Inside that same spot it looked pretty good. You could see the line coming through, so it was probably not getting into the wall, so probably fine.
Higher up, some of the tape was pulling away and there was some bulging. If an air sample comes back positive in that area, you know that might be a potential spot: there's a crack, there's some water damage. That's the kind of thing you're looking for around the outside.
Then Work Through The Inside
Once you've scoped out the outside, it's time to go in and go through the house with a fine tooth comb, looking in every nook and every cranny to see where there might be a potential issue.
- Give extra attention to anywhere in the home where there could be water. Look in, around and underneath the sinks, in all the bathrooms, around the toilet, at the area by the washer and dryer, and near and around the showers. These are the places that usually have issues.
- Lift up the lid on the toilet tank. Look at the top of the tank and the inside of the tank. In a bathroom that's a very good indication of whether you have a moisture or mold issue, because the tank acts sort of like a petri dish: a very dark and damp place where airborne mold in the bathroom will congregate.
- Check the vents. Ideally you have a screwdriver so you can unscrew the vent and pull it off, but normally when you do have a mold problem, you'll be able to see it on the grill of the vent.
- Once you find something, verify with the heat mapping tool and the moisture meter whether you have an active moisture problem.
What The Walkthrough Turned Up
The first spot came up ten minutes into the assessment: a wet area, so a leak of some kind, with visible mold. Then material falling, source unclear, and looking up, more mold growth, which made two spots. In the bathroom there was a little bit of water around the toilet, so possibly a wax ring problem, and mold visible in the cracks of the tile, which made that area a suspect spot for sampling. A third spot of mold, then more growth back up inside another area, and a section that looked like water had intruded and turned out to be saturated.
Asked how bad the house was, Ryan's answer was that they were finding mold in four locations already, thirty minutes into the process, with four visible spots of mold. His verdict: this home is pretty moldy.
The Jaspr Air Scrubber
One thing worth pausing on from that house is the Jaspr air scrubber, which is an industrial-grade air purifier. If you're dealing with active mold exposure, or you just want to have the healthiest environment possible, this is the best machine that you can get. I've personally tested a bunch of air purifiers and the Jaspr air scrubber always comes up on top. They even did a third-party test verifying that it was able to remove 100% of airborne mold spores in just two hours in a 500 square foot room at the highest fan speed.
I personally have one in my bedroom and it's been an absolute game changer. It doesn't necessarily fix the mold problem. You have to get rid of the water leak and remediate the area. But it definitely lowers the burden of the mold spores on your body, which can buy you some time and protect your immune system.
- Filter: a massive steel-reinforced carbon and HEPA filter
- Sensor: extremely sensitive, picks up anything in the air, and when the particulate goes up the fan speed automatically kicks up as well
- Warranty: lifetime, so if anything goes wrong you'll be taken care of
The Four Tests
There are four types of tests that help build a really clear picture of what's going on in the home, and it's important to do all of them, because they all have their own flaws and shortcomings. When you aggregate all the data together, that's what helps you build the case you might eventually need to use with a landlord, a builder or an insurance company, so that you can actually get things remediated, or get out of the lease, or whatever it is you're trying to do.
- Air sample: test the air outside and inside, especially in the places where you suspect that there's a problem.
- Tape sample: put the tape on the active water damaged spot, or where you suspect that there is mold.
- Swab sample: take a Q-tip and run it through the mold itself, then put that into a little vial.
- Surface sample: wipe down and collect dust throughout the house, in the vents, and in all the different places where there are potential problems. That gives you an indication of what type of mold is attaching to the dust that's settling.
Ryan's Recap Of The Inspection
Once we'd wrapped up testing the house, I asked Ryan for a quick recap of what went down.
- Talked with the client and got a history of what's going on. She's not feeling well in the apartment. Her health was fine, she moved in, and now she's having problems. She said there was some water damage.
- Came prepared and suited up.
- Went through the outside of the house looking for water intrusion points. Mold needs water to grow, so you're looking for water sources. Nothing could really be identified from the outside, which was good.
- Went on the inside with the thermal imaging camera and the moisture meter, looking for water spots. They found wet locations underneath the sink, above the cabinetry in the master bathroom, and in the ceiling. All of those places did have identifiable mold.
- Went through the home with a good visual inspection and did the sampling at the locations where those water spots were found. That identifies the sources and gives you a confirmation that yes, these are mold, and what kind they are, because different types of mold need to be treated differently.
