Granite doesn’t have an R-value. This common misconception stems from confusing stone with insulation materials like fiberglass or foam. R-value measures thermal resistance in insulating materials, indicating how well they prevent heat transfer through a building envelope. Granite, as a dense natural stone with high thermal mass, operates on entirely different thermal principles.
What granite actually possesses is thermal conductivity, measured in BTU/(hr·ft·°F) or W/(m·K), which ranges from 1.7 to 4.0 depending on mineral composition and density. This measurement tells you how quickly heat moves through the material, not …









