Cast stone has low porosity and can surpass the capabilities of natural stone on permeability. The absorption of cast stone is measured by the Capillary Absorption Test (CAT), full details of which are available to download here.
Cast stone can also weather in a similar fashion to natural stone. Research carried out by the University of Dundee confirmed that semi-dry cast stone weathered in a similar way to natural stone when both samples were exposed to identical atmospheric conditions.
On the other hand, wet cast stone tends to retain its supplied appearance for longer.