So when we bought this house in 2012, we knew there were some issues with moisture in the crawlspace. There was evidence of past “flooding” under the water heater, and the master bathroom. The crawlspace had no vapour barrier, and was open to the outside by way of crawlspace vents. It was damp, musty smelling and there were obvious signs of past and present animal and insect infestation. In many places the insulation was falling out of the floor joist bays.

Fast forward to a couple of years ago… We had already decided to address the crawlspace issues in the form of adding a radon system and having it sealed and conditioned. You can read about those projects here. I still need to go back and add some more crawlspace pictures. In hindsight I should have taken some before pictures, but who wants a picture of a nasty damp crawlspace? Anyway, suffice it to say that before the radon system and the insulation was sprayed, it was a really unpleasant place to be. It’s still pretty unpleasant since moving around is mostly a belly crawl, but it’s vastly improved. When I was making the computer model of the house I had to spend many hours under the house with my laser measure to get an accurate measurement of the house and supports. I did this before any of the work was done on it and I am glad I did it then, because with the foundation walls sprayed I can no longer get an exact measurement. For both the radon remediation and the spray foam, the contractors let us know there was mold present. Before we hired anyone or attended to it ourselves, we wanted to see if the radon system and sealing would lower the relative humidity to the point where it was no longer active. I have a few hygrometers that tell me that the relative humidity in the crawlspace is below 50% which should keep the mold down, provided there is no active source and there is no source of water to keep it going. The Nest thermostats tell me that the humidity is currently 44% so it’s below the threshold for mold growth.

Even after the crawlspace projects, Yvonne and I were still noticing spots of mold in our bathroom. We thought that it was because there was no vent fan in the shower room, only in the toilet room. I’m calling it a room but it’s really the size of a closet. I added a vent fan to the shower room and cleaned up the mold spots, thinking it was fixed. A few weeks later they appeared again. So there was still a source of mold in the house.

I’ve been spending a lot of time in the crawlspace working on the electrical wiring. During this time I kept bumping into the humidifier and finally decided to remove it. Imagine my surprise when I opened up the the unit and found my source of mold. It seems that the vampire tap was allowing just enough water out to allow about 2 inches of mold to form in the bottom of the humidifier. I removed the unit and cleaned up the duct work as best I could, but realized that the duct work had been blowing mold all over the house for years. I ordered some UV lights for the ducts, and installed them. The air blows over them and the UV kills the mold. At least that’s what’s supposed to happen. We’ll see. These are the ones I ordered. The installation instructions were a little rudimentary, so on Saturday I sent an email to the address provided. I received a prompt reply which allowed me to complete the install, so points for them for being there on a Saturday.

I think at this point I’ve identified the sources of moisture that’s causing the mold. I just have to make sure that the mold that is still present is dead and then clean it up. Once I get the floors buttoned up, I’m going to rent a fogger and fog the crawlspace for mold. Afterwards, I’ll make sure that all visible signs are cleaned up. Finally, I have a crawlspace dehumidifier that I’ll install to ensure that the humidity doesn’t ever get above 50%.

I don’t know if this is toxic black mold, nor do I care. It’s mold, so regardless of its species, it’s got to go. Next time I’m in the crawlspace I’ll snap some pics.

2 thoughts on “MOLD!”

  1. Did you have to replace any wood beams that had mold on them? Or can you use a chemical to kill mold that is deeply embedded in the wood?

    1. Hey DeAnne,

      There wasn’t any structural damage to the floor joists, just mold growing on the surface. Spray bottle with mold killer and a cloth were enough to clean it up. Some of the rough cut lumber doesn’t wipe very well, but the humidity is controlled and there are no sources of water leaking any more, so I think I’m good. From what I’ve read, the mold goes dormant once there isn’t enough moisture around. I’m still going to fog the crawlspace once I get the all the sub flooring back in.


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