Illinois Roofing Practice Exam 2025 - Free Roofing License Practice Questions and Study Guide

The primary focus when determining how to re-cover an SPF (Spray Polyurethane Foam) thermoplastic or thermoset roofing system is the adoption of separation layers over fully adhered or mechanically fastened systems.

Using separation layers is essential in maintaining the integrity of the existing roofing system during the re-cover process. This approach helps to prevent potential issues, such as moisture retention and damage to the underlying layers, which can arise when new roofing materials are directly applied over the existing system. Additionally, separation layers facilitate easier future repairs or removals by creating a barrier that helps distinguish between old and new materials, ensuring that the original structure remains intact and functional.

In contrast, while multiple insulation layers or sealants may play a role in specific scenarios, they are not the primary focus in this context. Furthermore, applying a thicker layer of the existing material does not address the need for a structured layering approach, which is critical for long-term performance and durability of the roofing system.