Yes. Bonus rooms (over garages) typically have multiple heat-loss surfaces (knee walls, sloped ceilings, garage ceiling below). Foaming all of them as a continuous envelope often delivers 50%+ comfort improvement. Common Cincinnati pain point.
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Bonus rooms over attached garages are the most-complained-about temperature problem in Cincinnati housing stock. The reason is geometry: a typical bonus room has 4-6 thermally-weak surfaces (front and back knee walls, sloped ceiling sections following the roof line, flat ceiling section to the attic, exterior wall to one side, garage ceiling below). Each surface in pre-2000 construction typically has R-13 to R-19 fiberglass at best and almost never has air-sealing detailing. Heat losses compound. The foam package: closed-cell on the underside of the garage ceiling, closed-cell on the back side of both knee walls, closed-cell at the rim joist of the bonus room floor, closed-cell on the sloped ceiling to roof rafters. Total cost $4,500-$9,500 for typical Cincinnati bonus room. Comfort improvement is usually dramatic (15-25°F warmer in winter, 8-15°F cooler in summer). Our Cincinnati installers spec the package after thermal-imaging the existing condition. Cincinnati bonus-room thermal-imaging specifics: our Cincinnati installers commonly find 18-25°F surface-temperature deltas across knee-wall surfaces in pre-2000 Cincinnati bonus rooms during winter conditions. After foam install, those deltas typically drop to 4-7°F. The comfort difference (warmer, more even, fewer cold spots) is the most common piece of post-install homeowner feedback for bonus-room projects.