Where should expansion joints be placed in a roof assembly?

Expansion joints are critical components in a roof assembly because they allow for the natural movement and expansion of building materials due to temperature changes, settling, and other factors. Placing expansion joints in the same location as the building's structural expansion joints ensures that both the roof and the structure can move similarly, reducing the risk of stress-related damage. This alignment helps to maintain the integrity of the roof assembly, preventing issues such as cracks or leaks that could arise from misalignment during movement.

By ensuring that the expansion joints in the roof align with those in the building's structure, the roofing system can effectively accommodate expansion and contraction without compromising its overall performance. This coordination is especially important in larger buildings or those with complex roof assemblies, where significant movement can occur.

In contrast, placing expansion joints randomly, in areas where water pools, or near roof edges may not effectively address the movement dynamics of the building. These locations could increase the likelihood of roof failure due to untreated stresses or could even exacerbate pooling water issues, leading to additional problems such as leaks or structural damage. The correct placement of expansion joints plays a crucial role in maintaining a durable and functional roofing system.