Walls and Ceilings - Taping new drywall to old drywall.

I have installed drywall in my basement on the outside walls. The new drywall meets existing drywall on two inside corvers and at an existing ceiling. The existing walls and ceiling hahe a thin plaster texture coating and laytex paint. Do I need to prepare the existing walls and ceiling defore I apply tape and mud to join the new drywall?I also want to spray texture to all walls and ceiling. How do I prepare painted walls for spray texture?

CGraves

As long as the existing walls and ceiling are clean, you shouldn't have any real problems. Wash them twice with a TSP solution before you start, and make sure you get them well rinsed afterwards. Might need to lightly sand the painted areas where the tape joints will occur too. Use an 80 grit paper or sheetrock mesh. Don't remove the paint, just break the gloss.

Lefty's got this one. Don't take the chance at doing it again and sand the old board at the new joints.