It's mid-July in Fort Worth, and the same thing is happening in tens of thousands of houses right now — the second floor is unforgivably hotter than the first. Homeowners think it's the AC. Usually, it's the attic. Here's the actual physics of what's happening 140°F above your ceiling, the four-layer construction fix that solves it for $5,500 to $17,500, and why doing it in mid-July gets you real relief before August lands.