After old VCT (vinyl composition tile) has been removed from a concrete substrate sometimes lines that mirror the former location of the tiles appear during the early grinding steps. These lines or tile marks are called tile ghosting. Tile ghosting comes from moisture vapor transmission within or below the slab, from water and treatments applied on the former VCT above the slab, or both. The most common questions about tile ghosting are:
Will we be able to grind through these lines?
If the marks are from the top down as with marking from dirty or gray water, we can often grind off or shave off or at least minimize the presence of the tile marks. But if the marks are caused by vapor transmission up through the slab, then no matter how far down we grind, we will just keep finding the same lines, though perhaps wider and even more pronounced.
Will coloring the concrete hide the marks?
Coloring the concrete may help give the concrete more of an even tone, but although that may be interpreted as masking or covering up the issue, the truth is that the lines are still going to be visible.
Will the marks fade over time or are they permanent?
No, the marks will not fade over time and yes, they are permanent.
If I can’t live with these marks and still want the “look” of polished concrete what are my options?
Short of removing and replacing the current slab you have one option. We can prep-grind the surface, apply an epoxy primer, apply a polish-able concrete topping and finally polish that topping to the desired specifications.