What is considered the best substrate for asphalt shingles?

The best substrate for asphalt shingles is a solid roof deck. A solid roof deck provides a continuous and level surface that supports the shingles effectively. This continuity helps ensure proper adhesion of the shingles, prevents water infiltration, and enhances the overall durability and longevity of the roofing system. A solid deck, typically made of materials like plywood or oriented strand board (OSB), helps minimize movement and flexing, which can lead to premature wear or damage of the shingles over time.

In contrast, other options such as concrete bases or metal frames are not commonly used for asphalt shingles, primarily due to issues related to weight, installation complexity, or thermal expansion and contraction. Additionally, while plywood is a suitable material for roof decking, it alone does not constitute an entire substrate; it is part of a solid roof deck that provides the necessary structure for optimal shingle performance.