I dont hold expertise in the field of construction. However, as per my research, Orivesi Black Phyllite is considered to be durable and suitable for exterior use in various climates, including very sunny climates. It has been used in many outdoor applications, such as facades, cladding, steps, and paving, with good results. However, it is always advisable to consult with a professional expert before making any final decisions regarding the materials suitability for a particular project.