For tiling over tiles in bathroom walls you ll need to set up sheets of waterproof membrane in between the concrete wall and tiles.
Tile over basement wall.
Now use shears to cut where you marked and you ll have the perfect size piece for that opening.
Be sure you double check the fit with the paper backing still on.
Installing a tile floor in all or part of your basement lets you have some fun with design while still quickly covering up existing concrete floors.
Measure the distance from the edge of the wall to the edge of the last full sized tile installed on the row.
You can get this from construction or hardware stores.
Subtract 1 4 inch from that measurement to get the necessary tile size.