If you have a tiling project that has obvious imperfect tiles installed then it is simply because the tiler has not checked the tiles as he laid them.
New wall tile grout defects.
If the tile is not labeled as a floor tile or recommended for floor use choose another tile.
Whether the underlayment is uneven the.
Always grout the walls first for this how to grout tile project and after they re finished the floor.
Grouting is the final step of installing ceramic wall tile after the tile adhesive has fully cured.
Spread the material in sweeping arcs pressing it into the joints to fill them completely.
Pour a quart to half gallon of grout on the tiles.
Use a hard edged rubber grout float and hold it at a 45 degree angle.
Use this method for both pre mixed and powdered grout.
Smear the grout diagonally across the tile to force it deep into the joints and prevent it from being sucked back out as your float slides along.
Wall tiles are not strong enough to serve on floors.
The colorant separated and clumped together creating uneven color.
The first is to remove bad grout and re grout using a grout saw.
Are all visible flaws and the installer should put these tiles aside for when cut tiles are needed.
New grout that is discolored with dark or dirty looking spots a result of the installer adding too much water to the grout and then let it sit in the bucket to thicken up.
There are two solutions.
Work in a small area at a time roughly a 3 x 3 foot section.
Grouting is not difficult to do well but it is even easier to do poorly.
While tiling is a job that can be completed by a savvy homeowner there are a few issues that can arise from seemingly minor details.
Tile defects such as firing cracks craters bubbles pinholes smudged patter etc.
Although some softer tiles are strong enough to hold up to minor wear such as in a powder room soft tiles will likely break or become scratched over time in high traffic areas.
However with wear and tear and due to the lack of proper care different types of tiles defects may appear on tile surface such as buckled tiles cracked tiles faded tiles shade variation in tiles rust stains on tiles etc.