We are installing a high efficiency gas fireplace that also serves as a source of heat for the upstairs. We need to provide access through the tiled fireplace surround to the heating vent assembly that goes upstairs and the gas union on the left side of the fireplace. My solution is to use three custom size recessed doors from Acudor. See example of their recessed access door below. From their specifications the combination of door panel, door frame and the air gap between them appears to be 3/16âÂÂ, which would dictate the grout line width for the entire fireplace surround. We plan on using 18x18 porcelain tile cut down to fit the design shown below. NOTE: All tile panels will be the same color. The door panels are shown in a different color for clarity. We thought we would start on the door panel side first to make sure the grout lines coincide with the access doors, and then do the face of the fireplace surround. Below is a picture showing the side panel with scrap wood installed to show the location of the framing for the Acudor recessed access doors. We used a story pole to determine the location of the framing for the doors. Does anyone here have experience with installing these types of access doors in tiled surfaces? Are we on the right path? Comments appreciated. Thank you for taking the time to read my post and consider my questions.

We are also doing a slate fireplace surround, though we're having a contractor do it. I had the same question initially, since in most tile installations, there's usually a bullnose piece at the edge. However, our installer said that he'll put caulk on the edges that matches the grout color. From my understanding, you'd want a caulk to match the grout, since you want caulk where you have 2 different materials meeting. In our case, we're going with a sanded grout and a sanded caulk of the same color. Below is a link to a picture of the slate we're going with. Can't send a picture of the fireplace, since it won't be done for a few weeks. Here is a link that might be useful:

Not a pro (and I’d hire one to do this!) but ripping out and starting over will produce a better result. The tile on the floor should be level to the wood. Looks like it’s lower now. Also adding metal trim schluter to all exposed edges would finish it off. Also Consider pulling the interior wood trim (which they tried to cut around) off and replacing it post install.

What you perpose will probably work but i would certainly test how well skim coat adhears bfore appling it to intire surface. A possible candidate for skim coat is modified thin set advertised as adhearing to ceramic. Different approachs are cement backer board or wire mash fastened with screws. The key is knowing what's behind existing tile to drive screws into. Removing a tile might reveal plywood or cement board which would make it easy. Otherwise you could find studs with a stud finder. If locating screws doesn't workout,test various construction adhesives. Some sticks well to tile.