First of all, be very careful when using the wire brush that you remove only the loose material. Even though foundation brick is stronger than outside brick walls, it is still a relatively soft material. Secondly, make sure that you use muriatic acid as your cleaning material. There are several reasons for using this. It will etch into the brick a little bit and better prepare it for the coat of paint. It will also neutralize any alkyds in the mortar and brick that can prevent the paint from bonding to the surface. Since you want the paint to be able to breathe, you have two choices. The easier, but not as durable, method is to apply an exterior latex paint. A longer-lasting choice is a cementitious paint. This thick and creamy mixture has portland cement mixed in, and will bond to the surface much better than regular paint.