and you need it to breathe. Putting anything on the surface that traps water will mess things up quickly. Sounds like they put the wrong paint/sealant which sealed up all the pores while allowing water to permeate through it.

Bricks have weeps to allow air flow in the cavity. Concrete is fine as long as you put the proper water proofing membrane on the outside. Stucco can go sideways pretty fast if not done properly and just like brick, it needs to breathe. But an even worse exterior is EIFS. Be happy you don't have that.