The petrological fabric of roofing slate determines the main properties of the slate as a construction material, such as durability and waterproofing. Roofing slates are rocks derived from the low-grade metamorphism of lutites, with a characteristic lepidoblastic fabric. However, little attention by petrologists has been paid to the role of this fabric in the behaviour of roofin slates. This work characterizes the fabric and pore system of two roofing slate varieties from Spain, using two different techniques, each with its advantages and disadvantages: X-ray microtomography, useful to find heterogeneities and mineral inclusions on the slate bulk,and mercury intrusion porosimetry, which defines the pore system. The differentiation of mineral inclusions is very useful for predicting the weathering of a slate, while the definition of the pore system may help to understand how the slate will behave during its service life
