Cat pee in concrete

[Marc Cleverley]

Didnt see a previous BP topic on cat piss for concrete. We fell into this property for a great price, but the house reeks now. We are worried about the walls and the concrete since it is porous. Any ideas on how to remove the smell. We plan on using killz on the wall, but I want to make sure the smell doesn't come back 3 months from now also.