Which of the following areas is NOT typically checked for insulation performance?

Insulation performance is fundamentally centered on how well insulation materials are functioning in keeping heat in during winter and out during summer. The primary focus is to evaluate physical aspects such as density, thickness, and placement of insulation materials.

Knee wall attics, attic slopes, and attic flats are all critical areas where insulation performance is directly assessed. Each of these locations plays a significant role in the overall thermal envelope of a building. For instance, knee walls can lead to significant energy loss if not properly insulated, while the slopes and flats of an attic require careful inspection to ensure an effective air barrier and adequate insulation coverage.

On the other hand, the quality of interior paint does not impact the mechanical performance of insulation. While interior paint quality can be indicative of the overall condition of a home, it does not directly affect how well insulation performs in terms of temperature regulation and energy efficiency. Thus, assessing interior paint quality is not relevant when checking for insulation performance, making it the correct choice for this question.