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