A new report from experts in Europe who delve into the science behind roofing slate has been published.

Testing Natural Slate as a Fire Resistant Material

Another quality post by Victor Cardenes

Fake Roofing Slates


  • Roofing slates are metamorphic rocks used for building covers.
  • They have an important presence in European Architectural Heritage.
  • So far, there are no reliable data on its performance under fire conditions.
  • They submitted different types of roofing slates to temperatures up to 900 °C.
  • Results show a decrease on the bending strength and an aesthetical change to red hue.

All samples studied exhibited a reduction in their bending strength, together with an increase in water absorption. Likewise, the oxidation processes triggered by the high temperatures induced a general oxidation of the iron, lending all of the samples a reddish hue. On the other hand, the roofing slate samples proved to be non-combustible and did not release any toxic or hazardous fumes.


  • All samples acquired a reddish hue due to the oxidation of the Fe2+ to Fe3+, caused by firing.
  • Samples with carbonate minerals took on a whitish hue.
  • Iron oxides (hematite) started forming in samples BRA and BUR at temperatures above 600 °C,

Mechanical Behavior

  • General decay in the bending strength
  • Consequently, we can conclude that the constructive properties of roofing slates are significantly affected by an increase in temperature to 900 °C, the same range reached by domestic fires.
  • Therefore, the reutilization of roofing slates affected by fire is not recommended.
  • On the other hand, roofing slates proved to be a non-combustible material and did not release any toxic or hazardous fumes during the heating tests.

Trust the Science!

Even in the worst elements, slate holds up. What type of roof do you want protecting your family? Shingles are for the chicken coop and a class A roof guarding your most valuable asset is made of slate. These tests continue to prove that slate is the premier protective against nature. You don’t have to look much further than slate if you want a eco-friendly, durable, flame resistant roof that will last hundreds of years.