What symbol is commonly used to represent rigid insulation on blueprints?

Rigid insulation is typically represented on blueprints with a zigzag or hatched pattern. This symbol is useful for indicating different materials and their types, as it allows architects and builders to quickly identify where insulation is applied in a construction project. The zigzag pattern effectively conveys the idea of insulation's texture and form, distinguishing it from other elements on the drawing. This visual cue helps professionals ensure that they are discussing the right materials during planning and construction phases, clearly indicating where thermal resistance is intended to be installed.

In contrast, other line types used in blueprints serve different purposes, such as solid lines often indicating visible edges or structural components, and dashed lines commonly represent hidden lines or features that are not immediately visible. Therefore, the use of a zigzag or hatched pattern specifically for rigid insulation is a standardized approach that enhances clarity and communication in construction documents.