Tile ghosting is when faint grid lines from old tiles show through a polished concrete floor. It happens because tile adhesive and grout change the concrete's porosity, leaving ghost marks even after the tiles are removed. The good news - with the right grinding approach, we remove tile ghosting on almost every job.
If you have pulled up old tiles and can still see a faint grid pattern in the concrete, you are looking at tile ghosting. It is one of the most common concerns we hear from Auckland homeowners planning a concrete polish after a renovation. We have already written a detailed explainer on what tile ghosting is and why it occurs. This article focuses on the practical side - how Diamond Shine Concrete actually fixes it, what to expect from the process, and when ghosting might still be faintly visible after polishing.
What Causes Tile Ghosting in Concrete?
Before we cover the fix, it helps to understand why the marks are there in the first place. When tiles are laid on a concrete slab, two things happen to the surface underneath.
Adhesive penetration. Tile adhesive soaks into the pores of the concrete wherever it is applied. Over 10, 20, or 30 years, that adhesive bonds deeply with the slab. Even after scraping the surface clean, adhesive residue remains embedded in the top few millimetres.
Grout line compression. The grout joints between tiles create a grid pattern where the concrete was either left exposed or covered with a thinner layer of adhesive. These strips absorb moisture and stains differently from the adhesive-covered areas, creating visible lines in the slab.
Chemical changes over time. The adhesive alters the concrete's density and porosity in a grid pattern. When you grind the surface, the treated areas and untreated areas respond differently to the polishing process - they reflect light at slightly different levels, which is what makes the ghost lines visible.
Tile Ghosting vs Other Floor Marks
| Mark type | What it looks like | Cause | Can it be removed? |
|---|---|---|---|
| Tile ghosting | Faint grid pattern matching old tile layout | Adhesive penetration into concrete pores | Yes - medium to heavy grind removes most cases |
| Tack strip marks | Row of small holes around room perimeter | Carpet tack strip nails (3-4mm deep) | Filled with colour-matched resin, blended with grinding |
| Glue stains | Random patches of discolouration | Carpet adhesive residue | Yes - needs heavy grinding (light grind smears it) |
| Levelling compound | Grey or white patches | Builder prep for previous flooring | Yes - grinds off cleanly |
| Moisture staining | Dark patches, often near walls | Rising damp or spills over decades | Partially - grinding removes surface stains, deeper moisture marks may persist |
How We Fix Tile Ghosting
Our approach to tile ghosting is straightforward - we grind past it. The ghost marks exist in the top few millimetres of concrete where the adhesive has penetrated. By grinding deeper, we get below the affected layer and into clean, consistent material.
Here is how the process works on a typical tile ghosting job.
Step 1 - Remove all remaining adhesive. Before polishing even starts, we use coarse diamond tooling to strip away any adhesive left on the surface after tile removal. This is not a gentle pass - tile adhesive needs a heavy cut to come off cleanly. Light grinding smears and burns adhesive rather than removing it, which is why we always start with aggressive tooling.
Step 2 - Assess the depth of ghosting. Once the surface adhesive is gone, we can see how deep the ghost pattern goes. On most Auckland homes, the ghosting sits in the top 2-4mm. We grind through test sections to confirm where the clean concrete starts.
Step 3 - Medium to heavy grind across the entire floor. This is the key step. We grind the entire floor to the same depth, past where the ghosting is visible. This typically means a medium to heavy grind - not a light salt-and-pepper finish. On older slabs, a heavier grind is needed regardless because the concrete is rarely flat after decades of settlement. DSC uses the same process across the entire floor for a consistent result.
Step 4 - Fill and repair. Any cracks, chips, or holes (including tack strip damage if the home previously had carpet in other areas) are filled with colour-matched resin.
Step 5 - Progressive polishing and densifying. We work through increasingly fine diamond grits, applying a densifier to harden and seal the surface. The final passes bring out the sheen and lock in the finish.
Why Light Grinding Usually Will Not Fix Tile Ghosting
If you have been looking into polished concrete finishes, you may have come across "salt and pepper" - the lightest grind level with minimal stone exposure. It is a popular look, but it is rarely the right choice for tile ghosting jobs. Here is why.
Salt and pepper only removes the very top layer of concrete. Tile adhesive typically penetrates 2-4mm into the slab. A light grind does not get deep enough to pass through the affected zone, so the ghost pattern remains visible - sometimes even more visible than before, because the grinding highlights the difference in porosity between the adhesive-treated and untreated areas.
Most tile removal jobs need a medium to heavy grind to get a clean, ghost-free result. The deeper cut removes the affected concrete entirely and exposes fresh aggregate beneath. This actually works in your favour - medium and heavy grinds reveal more stone in the concrete, creating a natural pattern with warmth and character that many homeowners prefer over a plain grey surface.
For a full breakdown of finish levels and what they look like, read our guide to polished concrete after carpet removal, which covers grind depths in detail.
Can Tile Ghosting Come Back After Polishing?
Once we have ground past the affected layer, tile ghosting does not return. The marks only existed in the top few millimetres of concrete that were altered by the adhesive. After grinding removes that layer, the floor is working with fresh, unaffected material.
However, there are two situations where faint marks may still be visible after polishing.
Very deep adhesive penetration. Some older adhesive types (particularly bitumen-based products used in the 1960s-1980s) can penetrate deeper than normal. In these rare cases, traces may remain even after a heavy grind. We identify this during our on-site assessment and will be upfront about what to expect.
Slab inconsistencies that mimic ghosting. Sometimes what looks like tile ghosting is actually a variation in the concrete mix itself - patches where the aggregate density differs. These are not caused by tiles and will not disappear with deeper grinding. Again, we flag this during the assessment so there are no surprises.
For the vast majority of tile ghosting jobs we handle across Auckland, a medium to heavy grind eliminates the ghost marks completely. Our recommendation is always a satin (semi-gloss) finish across the entire floor - it is the sweet spot between looks, durability, and stain resistance, and it gives the floor 20+ years of life with good maintenance.
What Does Tile Ghosting Removal Cost?
Tile ghosting jobs fall under renovation and restoration pricing. Because the work requires a deeper grind and more preparation than a standard polish, costs sit slightly higher than a straightforward new slab job.
| Job type | Typical price per m2 (+ GST) | Notes |
|---|---|---|
| Tile removal + polish (50-70m2) | $90 - $120 | Standard renovation pricing. Includes adhesive removal and grinding past ghosting |
| Restoration / regrind (existing polished floor) | $60 - $100 | For floors previously polished that need a refresh |
| Small areas under 20m2 | $2,250 flat rate | Minimum charge applies regardless of area size |
For a complete breakdown of polished concrete pricing in Auckland, including larger homes and commercial spaces, read our full cost guide.
Frequently Asked Questions
How much does it cost to fix tile ghosting in concrete?
Tile ghosting removal is part of our renovation pricing. For a typical Auckland home with 50 to 70m2 of floor area, expect $90 to $120 per m2 + GST. This covers adhesive removal, grinding past the ghosting, repairs, and polishing to a satin finish. Small areas under 20m2 have a minimum charge of $2,250 + GST. For full pricing details, see our polished concrete cost guide.
Will tile ghosting show through polished concrete?
It depends on how deep the grind goes. A light grind (salt and pepper) often leaves ghost marks visible because the adhesive has penetrated deeper than the grinding reaches. A medium to heavy grind - which is what we recommend for tile removal jobs - gets past the affected layer and eliminates the ghosting in most cases.
Can I polish over old tile adhesive without removing it first?
No. Tile adhesive must be removed before polishing. Adhesive residue prevents the diamonds from cutting evenly into the concrete, creating an inconsistent surface. It also interferes with densifier absorption, which affects the final finish quality. We remove all adhesive as the first step in our preparation process.
How long does it take to fix tile ghosting and polish the floor?
A typical residential job (50 to 70m2) takes 2 to 3 days. Day one covers adhesive removal, coarse grinding, and repairs. Day two is progressive polishing with densifier application. Day three is final finishing passes. You can walk on the floor immediately after completion.
Is tile ghosting the same as tile imprinting?
Yes - they are different names for the same thing. "Tile ghosting," "tile imprinting," "ghost marks," and "tile lines" all refer to the faint grid pattern left in concrete after old tiles are removed. The marks are caused by adhesive changing the concrete's porosity in a tile-shaped pattern.
Should I remove the tiles myself before you come?
You can remove the tiles yourself to save time on the job. Just be aware that removing the adhesive underneath is the harder part, and that is included in our service. Whether you leave the tiles in place or strip them yourself, the pricing is the same because the grinding and preparation work stays identical.
