We are remodeling our bathroom and need to frame around a vertical vent pipe that runs right through where the shower will be. The shower will run the width of the bathroom on the far wall (see picture). We are tiling the entire shower so the frame will have cement board on it and then the tile. We would like to get the frame as close to the vent as possible in order to optimize space in the shower. The problem is there is no wall stud where we want to start the frame. We'll lose a good 4 inches if we move the frame out to the wall stud. Any suggestions on how we can still frame around the vent and get as much space for our shower as possible? I can't nail the 2x4 into just drywall. Thanks.
You will probably have to open the wall and add framing to where you have to take off with your framing fro the mechanical chase. I am assuming that you are thinking about installing a shower pan and so are concerned about making a rectangular alcove? You can get creative and maintain the existing recess and simply make a shower of your design by implementing a kerdi system and making the shower pan the size and shape that you want if it will accommodate the dimensions of the existing alcove. Otherwise you can form a shower pan and make your own mud bed however I think this is more than you want to tackle.