Best Way To Seal Gap Between Ceramic

2 phillips bit a flat pry bar wood shims and a hammer.
Best way to seal gap between ceramic. What is the best way to fill these gaps. Fill gaps between 1 4 and 1 2 inch in width with two beads of caulk set side by side. So that gap is 1 2 wide and 1 4 deep throughout the center portion not including the 1 8 gap between the 2 plywood sheets which seems too big to fill with sealant to keep the ditra supported. The tile on the kitchen to living room gap starts about a quarter of an inch higher than the threshold and finishes about a quarter of an inch lower.
Apply one bead directly along the edge of the tub and the second bead along the edge of the wall. Hanging cement board is one job where gaps are desirable. Advice about gaps in cement boards. Gap between sheets of cement board.
I m willing to live with some visual imperfections. The gap between the taller plywood and the tub is 1 4 to 1 8 at the edges of the apron but as big as 1 2 in the middle. Use nails or screws as temporary spacers to create a 1 8 in. Above the tub lip to allow for movement of the tub and floor.
Examples where caulk is used to fill a gap include. Caulk is used to create a waterproof or insulating seal between building materials. At their widest the gaps are an inch wide and about a half inch deep at the deepest. If the gap between the countertop and backsplash is more than 3 8 inch it s generally too wide to fill and is best handled with trim but you can try to close the gap to give yourself the caulk option.