Which of the following is NOT included as a recommended substrate by HUD?

The choice of glass as a substrate is not recommended by HUD for reasons associated with its properties and practical applications in construction. Glass is not typically used in structural elements for which HUD guidelines aim to ensure safety, durability, and adaptability to weight and weather conditions.

In contrast, drywall, plaster, and concrete are common substrates that are favored due to their structural integrity, affordability, and ease of installation. Drywall is widely used for interior walls, plaster provides a smooth finish and can be applied to various surfaces, and concrete is a standard choice for foundations, walls, and surfaces requiring strong support and moisture resistance. The guidelines by HUD focus on materials that comply with building codes and support practices that lead to safe living environments.