Plain gypsum lath with aluminum foil laminated on one side as a vapor barrier and thermal insulation is called:

Plain gypsum lath with aluminum foil laminated on one side as a vapor barrier and thermal insulation is called:

• A. insulating
• B. reflective
• C. vapor-proof
• D. foil-lath

Answer: (A)

Insulating lath describes plain gypsum lath with aluminum foil laminated on one side because the foil adds thermal resistance and acts as a vapor barrier, reducing heat transfer and moisture movement through the plaster system. In practice, products with foil laminated to lath are categorized by their insulating function, not just by the presence of foil. While the foil can reflect some radiant heat and provide moisture protection, the defining label is the insulation provided to the wall assembly. Terms like foil-lath describe the construction, but they don’t emphasize the primary purpose, and vapor-proof focuses only on moisture control without highlighting the insulation aspect.

Insulating lath describes plain gypsum lath with aluminum foil laminated on one side because the foil adds thermal resistance and acts as a vapor barrier, reducing heat transfer and moisture movement through the plaster system. In practice, products with foil laminated to lath are categorized by their insulating function, not just by the presence of foil. While the foil can reflect some radiant heat and provide moisture protection, the defining label is the insulation provided to the wall assembly. Terms like foil-lath describe the construction, but they don’t emphasize the primary purpose, and vapor-proof focuses only on moisture control without highlighting the insulation aspect.