Charlie: Steven in Alief, he sends us one. He says, “I am a long-time fan and listener of you, Tom, and have called in a couple times, but now I have a question,” he writes, “that is too dumb for your radio show, so I’m going to read it on the radio show. He says “Why is an attic insulation put under the roof decking as well as in the, against the roof deck itself?”
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Tom: Well, you could put in the roof decking if you’re going to make a room up there and air condition it, but there’s no reason to put it against the roof decking, and fact it would be a poor idea because you want ventilation. We do ridge vents, soffit vents. If you put insulation there, it would block all the airflow, so that would be one.
The second thing is how can you do a radiant barrier if you have insulation up against roof decking because that’s where the radiant barrier goes? So that’s number two. And you also insulate against the skin of the condition space to keep the heat from transferring into the, in our case, into the room, and in Kansas cities in December, they don’t want the heat leaving the house because it gets cold there. So it’s just where it needs to be, against the skin of the condition space.