The bonus room, above the garage, was the coldest place in the house in winter, and the hottest in summer. Air was coming in through the trim/baseboard, and the sub-floor itself was very cold in winter. The goal Omni Services (OS) and I agreed to was to provide a year-round comfortable space. As a consumer, I wanted the room to be "air tight" but OS could not guarantee that. In preparation for the bonus room work, I removed the trim, carpet and pad for later re-use, and cut out (as best I could) some agreed-on 4x8 and 4x12 sections of the existing drywall, so we could see what was going on inside the walls and ceiling. The scope-of-work document had Omni Services (OS) removing the sub-floor as well, to check out the insulation beneath it, but ultimately OS didn't deem that necessary, as they found a different way to add insulation. [So in hindsight I removed the carpet and pad unnecessarily.] OS determined: a. the ceiling insulation was wrong for the space (R30 was crammed in, R19 should have been used) b. the roof above the bonus room (2x8 boards between the ceiling and the roof) had insufficient ventilation c. there was insufficient insulation in the garage attic (adjacent to the bonus room) that was a continuation of the roof above the bonus room What OS did for the ceiling: a. removed the R30 from most of the ceiling b. installed "proper vent" (a way for air to flow between the lower and upper parts of the roof) where the R30 had been c. replaced the R30 (that was removed) with R19 d. added some exterior ventilation (around the gutters and in the garage attic) to allow more air into the "proper vent" NOTE: I had a roofing company install ridge-cap ventilation above the bonus room; OS's work was pointless without that What OS did for the garage attic adjacent to the bonus room: a. install foam board insulation over the sloping area (continuation of the bonus room roof, into the attic) b. spray in more insulation What OS did for the sub-floor: a. accessed the underside of the sub-floor from either the garage attic or the limited space between the bonus room walls and the ceiling (which continued downward into the garage attic) b. sprayed in more insulation THE BAD: Once the drywall was replaced, taped, etc., and before the trim was put back on, there was still significant airflow into the room, where the drywall met the sub-floor. I had not expected this, nor had OS. I "fixed" this by using a combination of low-expanding foam from a can, leftover fiberglass insulation, and drywall mud. Air was also coming in from the drywall holes cut for the electrical boxes, but styrofoam covers fixed that. What OS did for the main attic stairs (accessible from the bonus room): a. manufactured a cover using leftover foam board and other materials b. installed the cover above the pull-down attic stairs c. sprayed in more insulation in the attic, in the area around the new cover What OS did for the doors: After I removed the trim from the French doors, OS replaced one of the doors, which had warped. I painted the door, then OS reinstalled the trim. BOTTOM LINE: We do not yet know whether the bonus-room goal was met. We won't know until we have a string of really hot days, and another string of really cold days.