Illinois Roofing Practice Exam 2026 – Complete Exam Preparation Guide

Interlayment in wood shake roof systems is essential for proper installation and function. Its primary purpose is to layer between each course of wood shakes, which helps to enhance the performance of the roof. This added layer works to improve water shedding, reducing the likelihood of moisture penetration into the underlying roof structure. By placing interlayment between the shakes, it also facilitates better ventilation, allowing air to flow and moisture to escape, further reducing the risk of rot and decay in the wooden shakes.

This aspect of interlayment is crucial for maintaining the longevity and durability of the roofing system. It contributes to the overall aesthetics of the roof by creating a more uniform look while ensuring that each shake maintains its intended position and overlaps properly, which is vital for effective weather resistance.