I am tiling using 6x6 itailian porcelian onto a 1/2 GP fiberglass moisture/mold resistant drywall.. double drywall ring nailed 16" oc with a drop light centered in the drop celing.. would it be advised to use thinset or go mastic ? Another question, I want to use bullnose all around the perimeter of the three sides ( from the curb up the two sides and across.. from this vantage point after this sets.. I can work my spacers to the back wall of the ceiling with my last row being cut.. after this I can dry lay/ mark and measure full tiles from the finished ceiling to the bottom where I will make my cut.. I will of coarse predetermines these cuts for starting from off bottom pan using a top leveled line around the surround (three walls) I will also allow a shim margin of space between the first row cut on the bottom starter row using lattice shimsor spacers flat for minute spacing adjusting.. I will tile the curb using bullbose on both top edges with a grout line in center (door glider track will cover this seam.. lastly, the 2x2 floor tile I will start pattern, proportionnate to the center drain cuts, working out the four finished sides of my mortar pan. If this is not the recommended procedure or if someone could suggest a better start to finish tiling project, I would like to know if there is a better way to tile a shower? I'm using membrane with thinset mortar and for the tile as well.. just not sure if thinset to this drywall ceiling is okay or if mastic is better to use, thanks in advace , jon

Wow you have it pretty planned out! I would never use mastic in a wet area. I would also recommend switching out to a cement backer board. You can use the sheetrock if need be. The main reason for switching to backer board is the security with ceiling tile. You should use a technique called "locking it in" when installing a ceiling tile. Use the flat side of the trowel & screed in a thin, thin layer of latex modified thin-set first. Next apply the mortar to the tile & press it in. This will allow the tile to create a vacuum with the board. I have hung 24 x 24 tile on ceiling & never had problems but is is difficult using sheetrock.

guru, every wall except the ceiling (which is sound and tight fiberboard George Pacific 1/2 sheetrock) the old ceiling was just drywall with mastic!. it was solid during my demo!. I know this drywall is even better on the ceiling//sure I could have went with hardiebacker but, it is below the wet line! Okay, I could use modified thinset as you explained! Thanks a bunch my man.. working upside down I thought the mastic would have made this easier.. but I understand you.. blade a thin flat over the ceil.. butter the tile.. got it!. now! // my ceiling goes on first// the surround bullnose, curb and pan using modified thinset with what I have now installed.. aqua-shield membrane. Tomorrow, I have to cut in recessed prefab shelf, so I need to start full from the top with my dry lay markings.. I need to drylay precisely to make my install cut for a recess-it shelf.. I think my perimeter should be bullnosed too along this thing( I want to try dry laying so I might be able to avoid cut tiles top and bottom of this recess-it this customer wants . I also have two borders and 12x12s half way up on straight and 6x6 diagnol after the border on the surround walls. Plus, this customer wants the extended bead thin border tile too.. this is going to take me a bit of ruler work! I'm thinking it best to keep the full row on top.. working down with spacers to find my cutout.. after this.. I can level line space to the pan.. make my cuts.. my walls are membrane so I'm not using a starter ledge with screws for my first starters.. what do you suggest I do so as not the use screws in the membrane for a starter ledge?

Had no problem using modified thinset everything is in order.My layout for the walls is an intricate designfrom bottom up with 12x12"s /border(4x12)" diagnol 6x6" another border of the same ,capped with a 2" pertruding border and 6x6 straight. This will be the three walls on the shower. The curb worked oout nice today along with the ceiling. I anticipate finishing the shower lay tomorrow. just got to find corner sheleves hopefully in the am.. ty guru and all for sharing!