White Mold vs Mildew and Efflorescence
Recently I was visiting my friends and they told me:
“We had our current home inspection, and the home inspector found efflorescence in our block wall in our basement. They were recommending that we take care of the problem in order to sell the house,
what should we do?”
Well, that’s a great question. And, first of all, just so you know, efflorescence is not mold. We’ve done test after test on that, and it never comes up as mold, so you don’t have to worry about that. What it is though, is it’s an indication of a water problem, either recently or in the past.
The calcium inside of the cinder block gets pushed out of the cinder block or the concrete and is visible on the wall whenever you have static pressure pushing that water out of the ground and into the cinder block wall of the basement.
Now, first of all, I want to describe what exactly efflorescence is.
Efflorescence is dissolved salts deposited on the surface of a material such as concrete or brick,
that are visible after the evaporation of water in which it was transported. The moisture that creates efflorescence often comes from ground water, but rain water can also be the source. Efflorescence does not pose a major problem, but it can be an indication of a moisture intrusion problem.
What all does that mean? Well, what that means for you is if you just recently had a home inspector that went in to the basement and they saw this white chalky stuff all over the walls of the basement, then they’re like, “Oh no, we’ve got a water intrusion problem, I’m going to write that on my report.”
Well, it doesn’t necessarily mean that it’s a current water intrusion problem, it could have happened 20 years ago and you fixed it whenever you had your downspouts and your gutters corrected.
So, it may not be an issue. So, what you have to do is you have to check the moisture level of the cinder block or the concrete, and that’s done with a moisture meter.
The other thing you got to be sure of is that how do you address the problem in the first place? Well, you may decide to put some kind of paint over it or something like that, but just be aware that if you do any kind of cover up like that, and you do have an active water intrusion problem, and the paint is not
able to withstand that intrusion, the static pressure, that’s coming through, the paint itself can become a mold food, and then not only do you have efflorescence on the block behind the paint, but now you got mold growing on that paint that you just installed, and we don’t want that.
Now, remember just a few minutes ago I said efflorescence itself isn’t mold, that salt that comes through the cinder block isn’t mold. But, if you’ve got a active moisture problem, that moisture that’s coming through the cinder block, the brick or the concrete wall, is evaporating into the space.
So, if you’ve got a basement or a crawl space, what is that doing?
It’s raising the humidity. And we all know what humidity level mold can grow at, right? Sixty percent, that’s right. So, what you got to do is if you have an active moisture problem, and you’ve tested the wall, and it’s wet, and every time you get a rainstorm it seems it’s getting worse and worse, you may want to install a dehumidifier in there to control that humidity, so that you don’t have secondary damage on your joist or your drywall depending on whether it’s a crawl space or a basement.
So, that would be a good idea to make sure you install a dehumidifier as quickly as possible to address at least the secondary damage of possible mold growing in that space.
So, what can you do to fix this problem?
Well, you can use an epoxy waterproofing paint, all right, which I don’t really recommend, because, like I said earlier, if that static pressure pushes through, it’s going to cause a mold problem in the future. But, basically what you have to do is you have to make sure that the gutters and the downspouts are draining away from the house. You want to make sure the slope of the yard is away from the foundation of the house. You know, just the basic things to make sure the water isn’t actively coming into the space, whether it’s a basement or a crawl space. But, what we do in crawl spaces that seems to satisfy the issue
here, with these home inspectors, is you can encapsulate the crawl space.
If it’s a basement, you may have to go with some sort of interior basement waterproofing, or perhaps an exterior basement waterproofing system, in order to keep that water from coming through the cinder blocks. So, keep an eye on those block walls and those concrete walls, and the brick for some of the older houses in the crawl spaces and basements, to make sure you don’t have an efflorescence problem.