How much space is required between the insulation and roof sheathing?

The correct amount of space required between the insulation and the roof sheathing is typically one inch. This space, often referred to as “ventilation space,” is crucial for allowing air circulation within the attic or roof assembly. Proper ventilation prevents moisture buildup, which can lead to mold growth, wood rot, and overall deterioration of the roofing structure. Adequate air circulation helps in maintaining a balanced temperature, reducing the risk of ice damming in colder climates and providing better energy efficiency.

While different building codes and practices may suggest variations, a one-inch gap is a common standard that meets the needs for effective ventilation without compromising insulation performance. Other measurements may not provide the same balance of insulation function and air movement, which is vital for the longevity and integrity of the roofing system.