Introduction to Metal Roofing System Substrates

By Anna Lockhart. 

Substrates are an important component in a metal roofing system. The metal experts at MBCI share their insights.  

Editor’s note: share this article with home and building owners interested in learning about metal roofing systems. 

Substrates, also known as substructures, are an important part of a metal roofing system and are the layer that metal panels are installed on. The roof's substrate layer provides a structural frame that supports the metal roofing materials. In other words, think of the substrates as the bones of a roof, supporting the exterior layers while protecting the structure beneath.  If a roof is installed correctly, the substrate should not be visible. 

The main functions of a substrate are its role as a base for which fasteners and clips are attached, securing the metal roofing panels in place, and as a structure that aids in bearing the weight load from any debris or mounted structures on the roof.  

While there are many kinds of substrates, in metal roofing, one of two types will be used: open framing and solid. Open framing substrates use individual pieces of wood or metal framing to secure the metal roof with structural style panels where the design supports the weight of the roof. Solid substrates, on the other hand, consist of solid metal sheets or wood laid closely together and are used with non-structural panels. In solid decking substrates, the roof membrane is applied atop the substrate.  

When planning a roofing project, it is important to consider the roof’s purpose and the type of building it will be built on so that your installers choose the right kind of substrate and additional materials.  

Visit the MBCI website to learn more about substrates, the role they play in a metal roofing system and how to choose the right substrate for your project.