It is not clear what Kirkby Tuff refers to as there is no specific information available. However, if Kirkby Tuff is a material or product designed for exterior applications, it would be essential to check its specifications and manufacturer recommendations.

In general, when selecting materials for exterior applications in very rainy climates, it is crucial to consider factors such as water resistance, durability, and ability to withstand prolonged moisture exposure. Materials like concrete, stone, and certain types of treated wood are commonly used in such environments. Additionally, proper installation techniques and regular maintenance may also be necessary to ensure the longevity and performance of the material.

Ultimately, it is best to consult with the manufacturer or a local professional to determine if Kirkby Tuff is suitable for exterior applications in very rainy climates. They will have specific knowledge about the material and can provide appropriate guidance based on its characteristics.