Which statement about building envelope components and their functions is correct?

• A. Foundations provide load transfer and moisture control.
• B. Roofs insulate and prevent water ingress; glazing has no role in light or heat transfer.
• C. Walls provide enclosure and insulation; roof prevents water ingress and insulates; glazing controls light and heat transfer.
• D. Doors and windows are only for access and do not affect energy performance.

Answer: (C)

Understanding how the building envelope works shows that each element has a clear role in comfort, durability, and energy performance. Walls create the enclosure and contribute to thermal resistance, helping to keep heat in during cold weather and out during hot weather. The roof serves as the main weather barrier and also provides insulation, reducing heat flow between interior and exterior. Glazing—windows and glass doors—controls how much light enters and how much solar heat is gained or lost, directly affecting daylight and energy use.

The statement that brings these functions together is the best fit because it describes walls as enclosers that also insulate, the roof as a barrier against water while providing insulation, and glazing as the element that governs light and heat transfer. Foundations mainly transfer loads to the ground, and moisture control relies on barriers and drainage rather than foundation function alone. Doors and windows do influence energy performance, not just access, since their glazing affects both light and thermal behavior.