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A while back I got an email from a homeowner who was puzzled. They have a home, doesn't have a
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basement, but it's a slab on grade arrangement. So that means the house is built on concrete that's
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been poured directly on the ground. This house has in-floor heating, but there's no insulation
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in the concrete floor. And the problem was that every summer the whole house smells musty. And
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the only way this homeowner could solve the problem was by running their dehumidifier all
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the time. That's an isolated incident, but it points to a much larger and much more common
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dynamic, especially as it applies to basements, even though this house didn't have a basement
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But what happens in the summer is you have warm, moist air, humid, compared with the ambient
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temperature in the summertime. So the warm, moist, humid air makes its way down, in the case of this
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homeowner, through some carpet and comes in contact with the cool concrete floor. That causes the
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temperature of the air to drop and the relative humidity to rise and you get actual minute amounts
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of condensation happening within the carpet pile and against the concrete floor. And that's the
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problem. So to solve the problem, you've got to stop the ability of that air to come in contact
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with the concrete floor. I mean, that's one solution. The solution to this homeowner was
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to run the dehumidifier to keep the humidity level down. And that's a good idea. In fact
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you shouldn't really be using a dehumidifier for that. An air conditioner is much better. You get
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a lot more drying power for a given amount of energy put into an air conditioner compared with
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a dehumidifier. But still, the best solution is to make it impossible for that air to come in
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contact with a concrete floor. It applies to above-ground situations like this reader
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but also, and much more commonly, to basements. And that's where the use of a basement subfloor
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like this comes into play. This is Dricor. It's probably the most widely available basement
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subfloor product. And it goes on like this. So we've got the dimpled plastic layer touching
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the concrete, raising the panel above the floor a bit. So you have a bit of a space here. Now
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in the case of a basement, the advantage there is if there's a small water leak, say a quarter inch
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or less, then you're really not going to notice it. It's not going to be a problem. That leaked
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water can still make it to a floor drain somewhere or even just seep right through the concrete
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which is fairly porous. So it protects against small amounts of moisture leakage. But more
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importantly, this plastic layer, quite thick really, functions as a vapor barrier. So with
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this on the floor and say carpet or hardwood floor on top of it, the warm moist air in the summertime
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can't get through. It can't get through to the concrete. There's an insulation action there
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caused by the airspace. But then there's also a vapor barrier action as well that stops that
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dynamic of the air making it through, cooling down, dropping down below the dew point and leaving
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some moisture behind. Of course, moisture triggers mildew and mold growth. The drier the better when
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it comes to your home. And basement subfloor tiles like this help to short circuit that dynamic of
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condensation, mold growth, and poor indoor air quality. That's really what this comes down to
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I mean, nobody likes a musty smell in their house. That's unpleasant. But the musty smell is also
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indicative of lower than it should be indoor air quality. And that's the main concern. That's the
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main reason for solving this problem
