Upside-Down Roof

Definition

An upside-down roof, also known as an inverted roof, is a membrane roof assembly where the thermal insulation lies above the waterproofing membrane.

Purpose

The design of an upside-down roof protects the waterproofing membrane from thermal stresses, mechanical damage, and ultraviolet exposure, extending its lifespan and improving overall roof performance.

Examples of Use

• Commercial Buildings: Using upside-down roofs to enhance the durability and energy efficiency of large commercial roofs.
• Green Roofs: Applying this system in green roofs to provide additional protection for the waterproofing membrane beneath soil and vegetation.
• Terraces: Installing upside-down roofs on rooftop terraces to allow for effective drainage and thermal insulation.

Related Terms

• Warm Roof: A roof where the insulation is placed above the structural deck but below the waterproofing layer.
• Cold Roof: A roof where the insulation is placed below the structural deck and the waterproofing layer is directly exposed.
• Waterproofing Membrane: A layer applied to prevent water penetration in roofs and other structures.

Notes

Upside-down roofs require specific insulation materials that can withstand exposure to the elements, such as extruded polystyrene. Proper drainage is also essential to prevent water accumulation above the membrane.