Polands Kopulak Sandstone can be used for exterior applications in very rainy climates, but its performance will depend on several factors.

Kopulak Sandstone is a durable and sturdy natural stone, often used in construction due to its strength and resistance to weathering. However, it is still important to consider the specific climate and conditions of the location where it will be used.

In very rainy climates, constant exposure to water and moisture can potentially cause some issues with sandstone. It is crucial to ensure that the sandstone is properly sealed and maintained to prevent water absorption which can lead to staining, cracking, or deterioration of the stone over time.

Additionally, it is important to choose the right type of sandstone from the Kopulak quarries, as some variations may be more suitable for exterior applications in rainy climates than others. Consulting with a local architect, stone supplier, or geologist who is knowledgeable about the specific geological properties and performance of Kopulak Sandstone would be beneficial in making an informed decision.