installing a new tile backsplash over drywall

[tom_matthews]

I just painted the sheetrock walls in my kitchen. Now I want to add a tile backsplash behind the sink. I know you're not supposed to install a tile backsplash on ordinary sheetrock. So I need to install greenboard I guess. However, if I install greenboard on top of the drywall (screwing it into the studs) then I'll need to conceal the greenboard at the top of the backsplash. Yet the bullnose tile edge pieces at the store don't have a deep enough bullnose to conceal the 1/2" of greenboard "reveal" that I'm going to create by putting greenboard on top of the drywall. So any advice on how to hide the greenboard at the top of the backsplash and make it look all perty?

Or, should I cut a strip of drywall out of the wall (the size of the anticipated backsplash), and then replace that missing drywall with a strip of greenboard cut to the same size? Is this a better way?

Keep in kind, I do not want to rip out ALL the freshly painted drywall and replace it all with sheets of greenboard. But I am willing to replace a strip if that's the proper appraoch to take.

AND, if I should install a greenboard strip, then should I mud and tape the joints like a regular drywall patch?

[Drywall DIY Guy]

For a sink area, you really should be using a "rock board". Green drywall is not waterproof - it will delaminate just like regular drywall if it gets wet. Green drywall is just more humidity resistant so it is used in bathrooms.

I would cut out an area of drywall slightly smaller then your tile area, cut out a piece of tile backer board to fit the cutout area, and shim up the backer board so the tile will sit flush with the surrounding wall. Fasten the backer. The tile will overlap onto the drywall slightly and at the same time seal up the outside perimeter well to prevent water intrusion. No taping will be needed since your tile glue & tile will seal the seam.

[tom_matthews]

Sweet! Thanks a million. That's just what I needed to hear.