We've been in our house now for 10 years and the walls and ceiling in our home have never been painted except for the kitchen wall and the bathroom walls. The builder had the walls and ceilings in all of the other rooms "plastered". The walls and ceiling have plaster board upon which they put a heavy skim coat on, and on the walls in the living room there is a pretty heavy 1/4 swirl texture. The kitchen and bath walls have a smooth texture to them. After 10 years of "living" in the house, how do I begin to prep the walls? If I wash them I would wash some of the grittiness of the sand in the texture off. The texture is pretty heavy, so how can I get the grooves in the texture clean enough to support paint? The walls are bone white throughout. I don't know how to begin, but I would like to paint to freshen and add some color.

I'm painting a friends house soon. I offered to do it for free but he's insisting to pay me. I don't know the square footage of the walls to be painted but I do know the floor plan is roughly 3800-4000 sq ft. I will be painting every room, all ceilings, as well as all trim. I'm just wondering what would be a reasonable price. Thanks!