i have brick walls in my basement that have alot of paint on them. i went out and bought a neddle scaler to remove it and all the other "stuff" that is on it. i am looking to water proof it and finish it. how clean does the bricks have to be to water proof it. should i sand it carefully when done scaleing it to get what i cant get off with the scaler. should i use cement to patch the cracks or use something else. the neddle scaler is working great just got to be carefull and take time doing it.